JP2023514057A - Power photodiode, method for connecting optical fiber to power photodiode, and optical fiber feeding system - Google Patents

Abstract

According to the present disclosure, techniques are provided for the fabrication and use of power photodiode structures and devices based on Group III metal nitrides and gallium-based substrates. More specifically, embodiments of the present disclosure include photodiode devices, structures, and device fabrication techniques that include one or more of GaN, AlN, InN, InGaN, AlGaN, and AlInGaN. Such structures or devices may be used in a variety of applications including optoelectronic devices, photodiodes, fiber optic powered receivers, and the like.

Description

FIELD OF THE DISCLOSURE The present disclosure relates generally to techniques for power transmission through optical fibers, and more particularly to techniques for high current density power photodiode structures and devices fabricated on polar, semipolar or nonpolar materials including bulk gallium and nitrogen. Regarding. The present invention is applicable to applications involving the conversion of light energy into electrical energy, particularly via optical fibers, other optoelectronic devices and similar products.

Power is typically transmitted through wires, for example copper wires. However, such wires are heavy, cumbersome and expensive, and the transmitted power can be subject to electromagnetic interference. Some of these constraints can be overcome by transmitting power through optical fibers, but unfortunately such an approach remains economically unfeasible with current capabilities. Furthermore, current approaches generally use infrared wavelengths of light, which has the disadvantages of being more susceptible to temperature changes in the surrounding environment than visible light or visible light radiation.

Gallium nitride (GaN) based optoelectronic and electronic devices are of great commercial importance. The best developed of these devices include light emitting diodes (LEDs) and laser diodes, with increasing importance of GaN-based power diodes and transistors. In addition, there is interest in new use cases. Non-Patent Document 1 converts electrical power into optical power using a laser diode, couples the optical power into an optical fiber for transmission to a remote location, and then converts the optical power back into electrical power using a photodiode. An example of conversion is described. Both laser diodes and photodiodes were based on GaN-on-sapphire devices and had relatively poor system performance. A photodiode with a reported efficiency of 17% was particularly problematic. GaN-based solar cells have also been reported by a number of groups, but typically for low power (about 1 SUN (100 mW/cm ² )) applications, using GaN-on-sapphire structures. rice field. Even well-known concentrator solar cell structures for other material systems are generally only capable of producing low current densities, which is the primary focus of this invention.

In the case of laser diodes, GaN-on-GaN devices are known to provide superior performance and reliability, which greatly reduce defect densities and have been optimized and improved over the years. It's been a long time. Much less work has been done in the case of photodiodes. For example, D'Evelyn et al., US Pat. No. 5,300,300, discloses a GaN-on-GaN photodiode intended for use in photodetectors rather than for power diode applications.

Related applications using GaAs-based lasers and photodiodes at near-infrared wavelengths are also disclosed. Nevertheless, the larger bandgap of nitride-based photodiodes compared to corresponding GaAs-based devices and systems should allow significantly higher open-circuit voltages and better efficiencies at high temperatures and input power levels. .

U.S. Pat. No. 6,806,508

Co-authored by De Santi, Material 11, 153 (2018)

Thus, it can be seen that techniques for improving GaN-based power photodiodes and methods of optical coupling thereto are highly desirable. Further, there is a need for systems, devices and methods that solve the above problems.

Embodiments of the present disclosure may provide a photodiode structure that includes a substrate having a first surface and a second surface, the second surface of the substrate opposite the first surface, and The substrate is a single crystal group III metal nitride, and the first surface of the substrate is the (0001)+c-plane, {10-10}m-plane, or {11-2±2}, {60-6± 1}, {50-5±1}, {40-4±1}, {30-3±1}, {50-5±2}, {70-7±3}, {20-2±1} , {30-3±2}, {40-4±3}, {50-5±4}, {10-1±1}, {10-1±2}, {10-1±3} 1 have different crystallographic orientations within 5 degrees from one of the selected semipolar planes, or at an angle between 2 and 5 degrees from (000-1). The photodiode structure also includes an n-type layer and a p-type layer disposed over the first surface of the substrate, the n-type layer and the p-type layer each being Al _x In _y Ga _1-xy N with 0≦x, y, x+y≦1 and having a dopant concentration of at least 1×10 ¹⁷ cm ⁻³ , and the one or more absorbing layers are between the n-type layer and the p-type layer and the one or more absorbing layers comprise Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dislocation density of less than about 10 ⁹ cm ⁻² . wherein the p-side electrical contact layer is disposed on the p-type layer and the p-side electrical contact layer has an average of at least 70% for at least one wavelength between 390 nanometers and 460 nanometers having a reflectivity and a connection resistance of less than 3×10 ⁻³ Ωcm ² , an n-side electrical connection layer disposed on the second surface of the substrate, the n-side electrical connection layer having a thickness of 390 having an average reflectance of at least 70% and a contact resistance of less than 1×10 ⁻³ Ωcm ² for at least one wavelength between nanometers and 460 nanometers; a light-receiving surface having at least one wavelength between 390 nanometers and 460 nanometers; Aligned to reflect at least once from the connecting layer. The photodiode structure can also be characterized by a fill factor of at least 50% under light irradiation level conditions that produce a current density of at least 10 Acm ⁻² .

Embodiments of the present disclosure further include one or more absorber layers, n-type and p-type layers, carrier substrates, p-side electrical contact layers, p-side reflective layers, n-side electrical contact layers, n-side reflective layers, and , a photodiode structure comprising a light-receiving surface, the one or more absorbing layers comprising Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 A, one or more absorber layers disposed over the n-type layer, a p-type layer disposed over the one or more absorber layers, and a carrier substrate having a first surface and a second surface. a first surface of the carrier substrate disposed over the p-type layer or under the n-type layer; a p-side electrical contact layer disposed in electrical contact with the p-type layer; The connection layer has a connection resistance of less than 3×10 ⁻³ Ωcm ² , a p-side reflective layer disposed on one of the p-type layer and the second surface of the carrier substrate, the p-side reflective layer has an average reflectance of at least 70% for at least one wavelength between 390 nanometers and 460 nanometers; The connection layer has a connection resistance of less than 1×10 ⁻³ Ωcm ² , an n-side reflective layer disposed on one of the n-side layer and the second surface of the carrier substrate, the n-side reflective layer has an average reflectance of at least 70% for at least one wavelength between 390 nanometers and 460 nanometers, and the receiving surface has at least one wavelength between 390 nanometers and 460 nanometers , are aligned to reflect light incident on the light-receiving surface at an angle from the n-side reflective layer and the p-side reflective layer at least once. The n-type layer and the p-type layer each comprise Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dopant concentration of at least 1×10 ¹⁶ cm ^{−3 .} have. The carrier substrate is substantially transparent at wavelengths between 390 nanometers and 460 nanometers.

Embodiments of the present disclosure further comprise a substrate having a first surface, a second surface and a third surface, an n-type layer and a p-type layer, one or more absorber layers, a p-type electrode layer, an n A photodiode structure can be provided that includes a type electrode layer and a light receiving surface, the n-type layer and the p-type layer disposed over a first surface of a substrate, and one or more absorbing layers comprising: disposed between the n-type layer and the p-type layer, the p-type electrode layer disposed on the p-type layer, the n-type electrode layer disposed on the second surface of the substrate, and the third surface includes a light receiving surface configured to reflect light received therethrough at least once between the n-type electrode layer and the p-type electrode layer. The n-type electrode layer includes an array of openings formed therein and has an average reflectance of at least 70% at wavelengths between 390 nanometers and 460 nanometers. The p-type electrode layer includes an array of apertures formed therein and has an average reflectance of at least 70% at wavelengths between 390 nanometers and 460 nanometers. The one or more absorber layers comprise an Al _x In _y Ga _1-x-y N material with 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ⁹ cm ⁻² . The n-type layer and the p-type layer each comprise an Al _x In _y Ga _1-x-y N material with 0≦x, y, x+y≦1 and a dopant concentration of at least 1×10 ¹⁶ cm ⁻³ have The second surface of the substrate is opposite the first surface, the third surface of the substrate is aligned at an angle to the first and second surfaces, and the substrate is a single crystal III group metal nitrides, and the first surface of the substrate is the (0001)+c-plane, {10-10}m-plane, or {11-2±2}, {60-6±1}, {50- 5±1}, {40-4±1}, {30-3±1}, {50-5±2}, {70-7±3}, {20-2±1}, {30-3± 2}, {40-4±3}, {50-5±4}, {10-1±1}, {10-1±2}, {10-1±3} It has a different crystal orientation within 5 degrees from the polar plane or at an angle between 2 and 5 degrees from (000-1).

Embodiments of the present disclosure can include photodiode structures that include one or more absorber layers positioned between an n-type layer and a p-type layer, wherein the absorber layer and the n-type layer and the p-type layer each comprises Al _x In _y Ga _1-x-y N, with 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ⁹ cm ⁻² ; The non-absorbing layers are each characterized by a dopant concentration of at least 1×10 ¹⁶ cm ⁻³ , and the absorbing layers are configured to efficiently power convert light having wavelengths between about 390 nanometers and 460 nanometers. and the structure is characterized by a fill factor of at least 50% under light irradiation level conditions that produce a current density of at least 10 Acm ⁻² .

Embodiments of the present disclosure may further provide an optical device that includes a die that includes one or more absorbing layers disposed between a first non-absorbing layer and a second non-absorbing layer, wherein one The absorbing layers and the first and second non-absorbing layers each comprise Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and about 10 ¹⁰ cm ⁻² and the one or more absorber layers each have a thickness measured in a first direction and a thickness parallel to the first plane and perpendicular to the first direction. and the die has a device cavity region with an optical window that internally reflects electromagnetic waves incident through the optical window to the one or more absorber layers, At least two opposing reflective members configured to be traversed at least two times.

Embodiments of the present disclosure may further provide an optical device that includes an optical window and a die that includes at least two absorbing layers, the at least two absorbing layers being an n-type first non-absorbing layer and a first non-absorbing layer. two non-absorbing layers, the absorbing layer and the non-absorbing layer each comprising Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and about 10 With a dislocation density of less than ¹⁰ cm ⁻² , a separate n-type contact is located on the first non-absorbing layer and a p-type contact is located on the second non-absorbing layer.

Embodiments of the present disclosure may further provide a fiber optic feeding module including at least one laser diode, at least one optical fiber, and at least one photodiode. _The laser diode includes at least one active layer, the at least one active layer including _{AlxInyGa1 -xyN} , where 0≤x, y, x+y≤1 and about 10 ⁷ It has a dislocation density of less than cm ⁻² . The laser diode is configured to have an emission wavelength between approximately 400 nanometers and approximately 500 nanometers. The photodiode comprises at least one absorbing layer, the at least one absorbing layer comprising Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and about 10 ¹⁰ cm It has a dislocation density of less than ^-2 . The photodiode is configured to have an absorber bandgap wavelength between about 400 nanometers and about 550 nanometers.

Embodiments of the present disclosure may further provide a fiber optic feeding system that includes at least one laser diode, at least one optical fiber, and at least one photodiode, wherein power from the photodiode is used to Power Internet of Things sensors or actuators or personal electronic devices. The laser diode includes at least one active layer, the at least one active layer including Al _x In _y Ga _1-xy N, where 0≦x, y, x+y≦1 and about 10 ⁷ cm It has a dislocation density of less than ^-2 . The laser diode is configured to have an emission wavelength between approximately 400 nanometers and approximately 500 nanometers. The photodiode comprises at least one absorbing layer, the at least one absorbing layer comprising Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and about 10 ¹⁰ cm It has a dislocation density of less than ^-2 . The photodiode is configured to have an absorber bandgap wavelength between about 400 nanometers and about 550 nanometers.

The fiber optic feeding module or fiber optic feeding system further includes at least one optical distribution device and/or control module for modulating the power of the laser diode with at least one controlled AC frequency and the photodiode A signal is separated into a DC power component and at least one AC signal component at a controlled frequency. In some cases, the amplitude of the modulated AC components of laser diode power and photodiode power is less than 10% of the amplitude of the corresponding DC components. In some embodiments, the AC signal component is modulated at an audible frequency and the module is connected to headphones or audio speakers. In some embodiments, at least one controlled frequency AC signal component is detected using the same photodiode that also converts the DC power component to electrical power. In some embodiments, at least one controlled frequency AC signal component is detected using a separate signal photodetector device. In some embodiments, a separate signal photodetector device is placed between the end of the optical fiber and one photodiode. In some embodiments, a separate signal photodetector device is positioned proximate to the optical coupling member, and the optical coupling member is positioned between the end of the optical fiber and the one photodiode. In some embodiments, the fiber optic feeding system further includes an internal reflector within the optical coupling member, the internal reflector comprising at least one of a metal, a dielectric, and an air gap of about 1 Has a maximum dimension of less than a millimeter.

In some embodiments of the fiber optic feeding module or fiber optic feeding system, the optical fiber has branching structures. In some embodiments of the fiber optic feeding module or fiber optic feeding system, the at least one laser diode comprises at least two laser diodes, the at least one photodiode comprises at least two photodiodes, and the module is configured to allow signal communication in at least two different directions. In some embodiments, at least one photodiode is configured to both input and output optical power. In some embodiments of the fiber optic feeding module, at least one non-rigid or non-contact optical coupling is used to accommodate rotation of the photodiode relative to the laser diode. In some embodiments, the fiber optic feeding system further comprises an illumination system that includes at least one of a phosphor, a heat sink, a reflective or transmissive optical element that forms a far-field distributed light, a sensor, and a control system. include. A lighting system may include a lighting fixture.

Embodiments of the present disclosure may further provide an optical assembly including a first die and a fixture. The first die includes one or more absorbing layers disposed between the first non-absorbing layer and the second non-absorbing layer, and an optical cavity region having an optical window, the one or more absorbing layers and the first and second non-absorbing layers each comprise Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and about 10 ¹⁰ cm ⁻² The fixture has a dislocation density of less than, and is configured to position the first end of the optical fiber a first distance from the surface of the optical window of the first die. The one or more absorbent layers each have a thickness measured in a first direction and an absorbent layer surface parallel to the first plane and oriented perpendicular to the first direction. The optical cavity region includes a device cavity region, the device cavity region including one or more absorbing layers, a first non-absorbing layer, a second non-absorbing layer, and at least two opposing reflective members, at least The two opposing reflective members are configured to internally reflect electromagnetic waves incident through the optical window to pass through the device cavity region at least twice.

Embodiments of the present disclosure may further provide an optical assembly including one die, the first die being a single die disposed between the first non-absorbing layer and the second non-absorbing layer. wherein the one or more absorbing layers and the first and second non-absorbing layers each comprise Al _x In _y Ga _1-x-y N, where 0≦x,y , x+y≦1, has a dislocation density of less than about 10 ¹⁰ cm ⁻² , and has a device cavity region with an optical window. The optical assembly may further include an optical element configured to receive optical radiation from the optical fiber and transmit the received optical radiation to at least a portion of the optical window. The one or more absorbent layers each have a thickness measured in a first direction and an absorbent layer surface parallel to the first plane and oriented perpendicular to the first direction. The device cavity region includes at least two opposing reflective members that internally reflect electromagnetic waves incident through the optical window to pass through the one or more absorbing layers at least twice. , configured to pass through.

In order that the features of the disclosure briefly described above may be appreciated, the disclosure will now be described in more detail with reference to embodiments, some of which are illustrated in the accompanying drawings. However, the attached drawings depict only exemplary embodiments and are therefore not to be considered limiting of the scope of the disclosure, as other equally effective embodiments are conceivable.

1 is a simplified illustration of a nitride-based power photodiode structure prepared according to embodiments of the present disclosure; FIG. FIG. 2B is a simplified illustration of an alternative nitride-based power photodiode die prepared according to embodiments of the present disclosure; FIG. 4 is a simplified illustration of another alternative nitride-based power photodiode structure prepared according to embodiments of the present disclosure; [0014] Fig. 5 is a simplified diagram illustrating fill factor definitions for photodiodes according to embodiments of the present disclosure; FIG. 4 is a schematic diagram showing the current-voltage behavior and fill factor of a photodiode according to a first comparative example of the present disclosure when illuminated; FIG. 5 is a schematic diagram showing the current-voltage behavior and fill factor of a photodiode when illuminated with light according to a second comparative example of the present disclosure; FIG. 2 is a simplified schematic of semiconductor layers within a photodiode structure according to embodiments of the present disclosure; FIG. 2 is a simplified illustration of photocurrent as a function of applied voltage for a photodiode structure according to embodiments of the present disclosure; FIG. 2B is a simplified illustration of local band structure as a function of position within a photodiode structure according to embodiments of the present disclosure; FIG. 2 is a simplified illustration of photocurrent as a function of applied voltage for a photodiode structure according to embodiments of the present disclosure; FIG. 2B is a simplified illustration of local band structure as a function of position within a photodiode structure according to embodiments of the present disclosure; FIG. 2 is a simplified illustration of photocurrent as a function of applied voltage for a photodiode structure according to embodiments of the present disclosure; FIG. 2B is a simplified illustration of local band structure as a function of position within a photodiode structure according to embodiments of the present disclosure; FIG. 2B is a simplified plot of photocurrent as a function of applied voltage for an illuminated photodiode according to embodiments of the present disclosure; FIG. 2B is a simplified illustration of photocurrent as a function of applied voltage for an illuminated packaged photodiode according to embodiments of the present disclosure; FIG. 4 is a simplified illustration of another alternative nitride-based power photodiode structure prepared according to embodiments of the present disclosure; [0012] Figure 4 is a simplified illustration of a method of removing a substrate from a nitride-based power photodiode structure according to embodiments of the present disclosure; [0012] Figure 4 is a simplified illustration of a method of removing a substrate from a nitride-based power photodiode structure according to embodiments of the present disclosure; FIG. 12 is a simplified illustration of another alternative photodiode die provided in accordance with an embodiment of the present disclosure; FIG. 2 is a simplified illustration of an alternative photodiode structure prepared according to embodiments of the present disclosure; 1 is a simplified illustration of a photodiode die prepared according to an embodiment of the present disclosure; FIG. 1 is a simplified illustration of a photodiode die prepared according to an embodiment of the present disclosure; FIG. 4 includes a table of illuminated IV performance characteristics of InGaN/GaN photodiode structures according to one or more embodiments of the present disclosure. FIG. 2 is a simplified illustration of an alternative photodiode die prepared according to an embodiment of the present disclosure; FIG. 2 is a simplified illustration of an alternative photodiode die prepared according to an embodiment of the present disclosure; FIG. 2 is a simplified illustration of an alternative photodiode die prepared according to an embodiment of the present disclosure; FIG. 2 is a simplified illustration of an alternative photodiode die prepared according to an embodiment of the present disclosure; FIG. 2 is a simplified illustration of an alternative photodiode die prepared according to an embodiment of the present disclosure; 1 is a simplified side view of a photodiode die according to an embodiment of the present disclosure; FIG. 1 is a simplified side view of a photodiode die according to an embodiment of the present disclosure; FIG. 2 is a simplified cross-sectional view of a photodiode die according to embodiments of the present disclosure; FIG. 2 is a simplified cross-sectional view of a photodiode die according to embodiments of the present disclosure; FIG. 1 is a simplified plan view of a photodiode die according to an embodiment of the present disclosure; FIG. FIG. 4A is a simplified diagram illustrating the path of light entering and traveling through a photodiode die according to an embodiment of the present disclosure; FIG. 4A is a simplified diagram illustrating the path of light entering and traveling through a photodiode die according to an embodiment of the present disclosure; FIG. 4A is a simplified diagram illustrating the path of light entering and traveling through a photodiode die according to an embodiment of the present disclosure; FIG. 4A is a simplified diagram illustrating the path of light entering and traveling through a photodiode die according to an embodiment of the present disclosure; FIG. 4A is a simplified diagram illustrating the path of light entering and traveling through a photodiode die according to an embodiment of the present disclosure; FIG. 4B is a simplified side view of a photodiode die according to an alternate embodiment of the present disclosure; FIG. 4B is a simplified side view of a photodiode die according to an alternate embodiment of the present disclosure; FIG. 4B is a simplified cross-sectional view of a photodiode die according to an alternate embodiment of the present disclosure; FIG. 4B is a simplified cross-sectional view of a photodiode die according to an alternate embodiment of the present disclosure; FIG. 2B is a simplified plan view of a photodiode die according to an alternate embodiment of the present disclosure; [0014] Fig. 4A is a simplified diagram illustrating the path of light entering and traveling through a photodiode die according to an alternative embodiment of the present disclosure; [0014] Fig. 4A is a simplified diagram illustrating the path of light entering and traveling through a photodiode die according to an alternative embodiment of the present disclosure; FIG. 2B is a simplified side view of a photodiode die according to another alternative embodiment of the present disclosure; FIG. 2B is a simplified side view of a photodiode die according to another alternative embodiment of the present disclosure; FIG. 2B is a simplified cross-sectional view of a photodiode die according to another alternative embodiment of the present disclosure; FIG. 2B is a simplified cross-sectional view of a photodiode die according to another alternative embodiment of the present disclosure; FIG. 2B is a simplified plan view of a photodiode die according to another alternative embodiment of the present disclosure; FIG. 4B is a simplified cross-sectional view of a photodiode die according to yet another alternative embodiment of the present disclosure; FIG. 4B is a simplified cross-sectional view of an array of photodiode dies according to yet another alternative embodiment of the present disclosure; FIG. 3 is a simplified illustration of a configuration of a fiber optic feeding module according to some embodiments of the present disclosure; FIG. 3 is a simplified illustration of a configuration of a fiber optic feeding module according to some embodiments of the present disclosure; FIG. 3 is a simplified illustration of a configuration of a fiber optic feeding module according to some embodiments of the present disclosure; [0014] Fig. 5 is a simplified illustration of a fiber optic feeding module configuration incorporating both power and modulated signals according to some embodiments of the present disclosure; [0014] Fig. 5 is a simplified illustration of a fiber optic feeding module configuration incorporating both power and modulated signals according to some embodiments of the present disclosure; [0014] Fig. 5 is a simplified illustration of a fiber optic feeding module configuration incorporating both power and modulated signals according to some embodiments of the present disclosure; [0014] Fig. 5 is a simplified illustration of a fiber optic feeding module configuration incorporating both power and modulated signals according to some embodiments of the present disclosure; FIG. 10 is a simplified diagram of detailed balance model efficiency calculations as a function of semiconductor bandgap at temperatures of 300, 400, 500 and 600 Kelvin; FIG. 4B is a simplified cross-sectional view of a photodiode die according to yet another alternative embodiment of the present disclosure; FIG. 4B is a simplified cross-sectional view of a photodiode die according to yet another alternative embodiment of the present disclosure; [0014] Fig. 4A is a simplified illustration of a fiber optic feeding module connected to a lighting system according to an embodiment of the present disclosure; FIG. 2 is a simplified light absorption model for packaged photodiodes according to embodiments of the present disclosure; FIG. 2 is a simplified light absorption model for packaged photodiodes according to embodiments of the present disclosure; FIG. 2 is a simplified illustration of a patterned substrate according to an embodiment of the present disclosure; 1 is a simplified side view of a photodiode packaged and connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a simplified top view of a photodiode packaged and connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a simplified top cross-sectional view of a photodiode packaged and connected to an optical fiber according to an embodiment of the present disclosure; FIG. FIG. 2B is a simplified bottom view of a photodiode packaged and connected to an optical fiber according to an embodiment of the present disclosure; 1 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an embodiment of the present disclosure; FIG. FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a packaged photodiode connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; FIG. 4 is a side cross-sectional view that schematically illustrates a photodiode packaged and connected to an optical fiber according to an alternative embodiment of the present disclosure; 1 is a side cross-sectional view that schematically illustrates a packaged photodiode and a separate photodetector connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a side cross-sectional view that schematically illustrates a packaged photodiode and a separate photodetector connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a side cross-sectional view that schematically illustrates a packaged photodiode and a separate photodetector connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a side cross-sectional view that schematically illustrates a packaged photodiode and a separate photodetector connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a side cross-sectional view that schematically illustrates a packaged photodiode and a separate photodetector connected to an optical fiber according to an embodiment of the present disclosure; FIG. 1 is a side cross-sectional view that schematically illustrates a packaged photodiode and a separate photodetector connected to an optical fiber according to an embodiment of the present disclosure; FIG. FIG. 2 is an isometric view of a fixture used to support a photodiode die and an optical fiber according to an embodiment of the present disclosure;

For clarity, identical reference numbers are used wherever possible to refer to identical elements that are common to the drawings. Without further recitation, it is contemplated that elements and features of one embodiment may be advantageously incorporated into other embodiments.

According to the present disclosure, techniques are provided for the fabrication and use of power photodiode structures and devices based on Group III metal nitrides and gallium-based substrates. More specifically, embodiments of the present disclosure include photodiode devices, structures, and device fabrication techniques that include one or more of GaN, AlN, InN, InGaN, AlGaN, and AlInGaN. Such structures or devices may be used in a variety of applications including optoelectronic devices, photodiodes, fiber optic powered receivers, and the like.

As already mentioned, lasers and photodiodes are being developed in the GaAs material system. One of the main differences between arsenide-based and nitride-based material properties is that in the case of arsenide, for example, through AlGaAs, the bandgap can be easily varied with minimal effect on the lattice constant. However, this is not the case for nitrides. Conventional photodiode package designs incorporating nitride absorber layers may require absorber layer thicknesses on the order of hundreds of nanometers to absorb most of the incident light. Assuming an absorption coefficient of 1×10 ⁵ cm ⁻¹ for the absorbing layer, the light absorbed in one pass is about 39% for thicknesses of 50, 100, 200, 300, and 400 nm, respectively. , 63%, 87%, 95% and 98%. In the case of nitrides, InGaN with enough indium (In) at such thicknesses to efficiently absorb blue or violet light is too strained to avoid relaxation by dislocation generation or cracking. sell. The inventors have found an approach that avoids this problem, which transmits the electromagnetic wave along a long optical path through the absorbing layer and is 100% effective even with a power photodiode structure containing a relatively thin absorbing layer. Including methods to achieve close optical absorption. Further advantages of this new approach include excellent heat dissipation, zero or very low lattice shadow loss, and long effective minority carrier lifetime. Here, the effective minority carrier lifetime includes photon recycling, defined as the reabsorption of photons emitted by the absorbing layer. The terms "light" and "optical radiation" are often used interchangeably herein, and both are generally intended to describe electromagnetic waves of one or more wavelengths, unless otherwise stated. .

In order to properly take advantage of arrangements involving long optical paths through absorbing layers, novel optical coupling arrangements, fixtures and methods are disclosed herein. Further advantages of the new optical coupling method include improved ease and accuracy of alignment, as well as improved efficiency, robustness, durability and longevity.

Furthermore, photodiode structures such as stacked epitaxially grown layers have both similarities and differences from light emitting diode (LED) and laser diode (LD) structures. For example, both LED and LD structures typically include an electron blocking layer within the p-type layer to minimize electron loss from the active region and promote radiative carrier recombination within the active region. However, such a structure can have the opposite effect by increasing the series resistance of the photodiode structure. Similarly, LD structures typically include one or more of cladding layers, optical confinement layers, and separate confinement heterostructure (SCH) layers that can impair photodiode performance, which is from a different perspective than the present application. because it was designed.

In order to design effective epitaxial structures for photodiodes, both in general and in the specific case where the active layer comprises or consists of InGaN or Ga(In)N, the active layer light absorption and minority A high carrier collection efficiency increases the detection sensitivity and the operating current _Imp . Low defect densities, both point defects and extended defects such as dislocations and stacking faults, reduce shock-lead hole non-radiative recombination, thereby increasing the operating voltage V _mp . In addition, the low defect density also improves photodiode performance under intense lighting conditions (ie, high optical power (watts) conditions). The photodiode efficiency η can be expressed as η=V _mp ×I _mp /P _in , where P _in is the input radiation power.

_Another way of expressing the _photodiode efficiency η is as _shown schematically in _{FIG .} , is the short circuit current and FF is the fill factor. Yet another way to express the efficiency η of a semiconductor photodiode is η=( _eVoc / _Eg )*OA*IQE*FF* _Eg /(hv) where e is the electron charge and _Eg is the bandgap of the semiconductor, OA is the optical absorptivity (or fraction of incident photons absorbed in the absorbing layer), and IQE is the internal quantum efficiency (resulting in collected electron-hole pairs is the fraction of photons absorbed), h is Planck's constant, and ν is the photon frequency. In preferred embodiments, FF is greater than 50%, greater than 60%, greater than 70%, greater than 80%, or greater than 90%.

Compared to conventional photodiodes designed for very low photon flux and mainly fabricated with GaN-on-sapphire structures, the photodiodes of the present invention comprising GaN-on-GaN structures have a semiconductor layer with careful optimization of the composition and doping of , and high reflectivity when used with multi-reflecting excitation structures, and large-area FETs with very low contact resistances that minimize lateral ohmic losses at high current densities. It is characterized by high conversion efficiency due to the p-side and n-side electrical connections. In one embodiment, the current photodiode structure is illuminated by a single laser or multiple lasers, as shown schematically in FIG. Designed for incident-on-object applications. In some embodiments, the laser light is coupled to the edge of the photodiode structure or to an aperture formed in the photodiode structure using an optical fiber, lens or waveguide. In certain embodiments, the photodiode structures of the present invention also incorporate very low dislocation densities and have long minority carrier diffusion lengths to enhance current, as well as to enhance open circuit voltage and fill factor. has a long minority carrier lifetime. In addition, the device of the present invention has a conductive substrate that allows vertical movement in a vertically oriented power device for simple design and reduced series resistance, and a refractive index very close to that of the absorber layer to reduce optical loss. and a transparent substrate that minimizes the In some embodiments, the substrate has a non-polar or semi-polar crystallographic orientation to allow tuning of the polarization field for optimum device performance.

1 and 3 are simplified diagrams of a Group III metal nitride based photodiode structure 1000, and FIG. 2 is a simplified diagram of a Group III metal nitride based photodiode die 1002. FIG. Referring to FIG. 1, a substrate 101 is provided. In some embodiments, substrate 101 comprises a single crystal Group III metal nitride, gallium-containing nitride, or gallium nitride. The substrate 101 can be grown by HVPE, by ammonothermal method, or by flux method. In some embodiments, the substrate 101 comprises _a single crystal Group III metal nitride layer 1104 on a template substrate 1101 consisting of or including a material such as sapphire ( _Al2O3 ), silicon carbide (SiC), or silicon. It is a template deposited or grown on the . In alternate embodiments, the template substrate 1101 is gallium arsenide, germanium, silicon germanium alloy, _MgAl2O4 spinel, ZnO, _ZrB2 , BP, InP, AlON, _ScAlMgO4 , _{YFeZnO4 ,} MgO, _{Fe2NiO4 .} , _LiGa5O8 , _{Na2MoO4 , Na2WO4 , In2CdO4} , lithium aluminate ( _LiAlO2 ) _{, LiGaO2 , Ca8La2} ( _PO4 ) _{6O2 ,} gallium nitride (GaN ₎ , Alternatively, it may consist of or include aluminum nitride (AlN) or the like. One or both of the large area surfaces of substrate 101 may be polished and/or chemical-mechanically polished. The large surface area 102 of the substrate 101 includes (0001)+c-plane, (000-1)-c-plane, {10-10}m-plane, {11-2±2}, {60-6±1}, {50 -5±1}, {40-4±1}, {30-3±1}, {50-5±2}, {70-7±3}, {20-2±1}, {30-3 ±2}, {40-4±3}, {50-5±4}, {10-1±1}, {10-1±2}, {10-1±3}, {21-3±1 }, or within 5 degrees, within 2 degrees, within 1 degree, or within 0.5 degrees of {30-3±4}. It will be understood that the {30-3±4} planes refer to the {30-34} and {30-3-4} planes. The large area surface 102 may have a (hkil) semipolar orientation, where i=−(h+k) and l and/or h and/or k are non-zero. In some embodiments, the template substrate 1101 consists of or includes sapphire and has (0001), (10-10), (10-12), (22-43), or (11-23) to 5 It has a large surface area 102 with a crystal orientation within 1 degree, within 2 degrees, within 1 degree, or within 0.5 degrees. In some embodiments, the template substrate 1101 is made of or includes sapphire and has (0001) to {11-20} a-plane, {10-10} m-plane, or intermediate between a- and m-planes. has large area faces 102 oriented in different orientations at angles between about 0.5 degrees and about 8 degrees, or between about 2 degrees and about 4 degrees, toward the plane of . In some embodiments, the template substrate 1101 is within 5 degrees, within 2 degrees, within 1 degree, or 0.5 degrees from the cubic structure and {111}, {100}, {110}, or {114}. It has a large surface area 102 with a crystal orientation within 5 degrees. Other orientations may also be selected.

In one embodiment, the surface 1102 of the template substrate 1101 is patterned and includes the template substrate 1101, the n-type first non-absorbing layer 105, the absorbing layer 107, the optional second non-absorbing layer 109, and the p-type layer. Alternatively, it facilitates optical transmission between the stack of p-type non-absorbing layers 111 . Referring to FIG. 30, surface 1102 can include a patterned array of features 1106 . Features 1106 may comprise or consist of cones, domes, hemispheres, triangular pyramids, square pyramids, hexagonal pyramids, or the like. Other shapes are also possible. Features 1106 may be characterized by pitch 1108 , height 1110 and width 1112 . Features 1106 can be arranged across surface 1102 in square, rectangular, or hexagonal arrays. Other patterns of features 1106 are also possible. Pitch 1108 can be between about 0.2 microns and about 10 microns, or between about 1 micron and about 5 microns. Height 1110 can be between about 0.1 micrometer and about 10 micrometers, or between about 1 micrometer and about 3 micrometers. Width 1112 can be between about 0.1 micrometer and about 10 micrometers, or between about 1 micrometer and about 5 micrometers. In one embodiment, template substrate 1101 is made of or includes sapphire and has a surface 1102 with a crystal orientation within about 5 degrees of (0001). In some embodiments, the template substrate 1101 can be referred to as a patterned sapphire substrate, as known in the art.

Large area surface 102 has a maximum dimension of between about 0.2 millimeters and about 600 millimeters and a minimum dimension of between about 0.2 millimeters and about 600 millimeters, and substrate 101 has a maximum dimension of between about 0.2 millimeters and about 600 millimeters. It can have a thickness of between about 10 millimeters, or between about 100 micrometers and about 2 millimeters. In some embodiments, substrate 101 is generally circular and has one or more orientation flats. In an alternate embodiment, substrate 101 is generally rectangular. In some embodiments, large area surface 102 has a maximum dimension of about 50 mm, 100 mm, 125 mm, 150 mm, 200 mm, 250 mm, or 300 mm. The change in crystal orientation of the large-area plane 102 is less than about 5 degrees, less than about 2 degrees, less than about 1 degree, less than about 0.5 degrees, less than about 0.2 degrees with respect to the average orientation of the large-area planes. , less than about 0.1 degrees, or less than about 0.05 degrees.

Large area surface 102 of substrate 101 is less than about 10 ¹⁰ cm ⁻² , less than about 10 ⁹ cm ⁻² , less than about 10 ⁸ cm ⁻² , less than about 10 ⁷ cm ⁻² , less than about 10 ⁶ cm ⁻² , about It can have a threading dislocation density of less than 10 ⁵ cm ⁻² , less than about 10 ⁴ cm ⁻² , less than about 10 ³ cm ⁻² , or less than about 10 ² cm ⁻² . Large area surface 102 of substrate 101 has a stacking fault density of less than about 10 ⁴ cm ⁻¹ , less than about 10 ³ cm ⁻¹ , less than about 10 ² cm ⁻¹ , less than about 10 cm ⁻¹ , or less than about 1 cm ⁻¹ . can have Large area surface 102 of substrate 101 is less than about 500 arc seconds, less than about 300 arc seconds, less than about 200 arc seconds, less than about 100 arc seconds, less than about 50 arc seconds, less than about 35 arc seconds, less than about 25 arc seconds or have a symmetrical X-ray rocking curve full width at half maximum (FWHM) of less than about 15 arcseconds. Large area surface 102 of substrate 101 extends in at least one or at least two independent or orthogonal directions greater than 0.1 meters, greater than 1 meter, greater than 10 meters, or 100 meters larger or may have a crystal radius of curvature greater than 1000 meters. In certain embodiments, the large area surface 102 of the substrate 101 has a threading dislocation density of less than about 10 ⁵ cm ⁻² , a stacking fault density of less than about 10 cm ⁻¹ , and a symmetrical X-ray locking of less than about 50 arcsec. It has a curve full width at half maximum (FWHM). The reduced dislocation density in the substrate 101 compared to most conventional photodiodes results in lower dislocation densities in the semiconductor layers of the photodiodes, higher open circuit voltage _Voc , and higher efficiency at high current densities. is expected.

In some embodiments, substrate 101 can include regions with relatively high threading dislocation densities separated by regions with relatively low threading dislocation densities. The threading dislocation density in the region of relatively high density is greater than about 10 ⁵ cm ⁻² , greater than about 10 ⁶ cm ⁻² , greater than about 10 ⁷ cm ⁻² , or greater than about 10 ⁸ cm ^{−2 .} It can be higher. Threading dislocation densities in the relatively low density regions can be less than about 10 ⁶ cm ⁻² , less than about 10 ⁵ cm ⁻² , or less than about 10 ⁴ cm ⁻² . Substrate 101 may also include or otherwise include regions of relatively high electrical conductivity separated by regions of relatively low electrical conductivity. Substrate 101 can have a thickness between about 10 micrometers and about 100 millimeters, or between about 0.1 millimeters and about 10 millimeters. Substrate 101 is at least about 5 millimeters, at least about 10 millimeters, at least about 25 millimeters, at least about 50 millimeters, at least about 75 millimeters, at least about 100 millimeters, at least about 150 millimeters, at least about 200 millimeters, at least about 300 millimeters, at least about It can have dimensions including a diameter of about 400 millimeters, or at least about 600 millimeters. In certain embodiments, substrate 101 has a thickness between about 250 microns and about 600 microns, a maximum lateral dimension or diameter between about 15 millimeters and about 160 millimeters, and a threading dislocation density of about Includes regions below 10 ⁴ cm ⁻² .

Substrate 101 may include an exfoliation layer 1103 to facilitate separation of single crystal group III metal nitride layer 1104 from the rest of the substrate, such as template substrate 1101 . In some embodiments, if the template substrate is substantially transparent and has a light absorption coefficient of less than 50 cm ⁻¹ , the exfoliation layer 1103 has a light absorption coefficient of greater than 1000 cm ⁻¹ at at least one wavelength, and allows the substrate to be removed after fabrication of at least one device structure, for example, by laser lift-off techniques. In one embodiment, the exfoliation layer 1103 comprises or consists of heavily Co-doped GaN, which enhances the optical absorption coefficient to greater than 5000 cm ⁻¹ over the entire visible light range. In one particular embodiment, a Co-doped exfoliation layer 1103 having a thickness between 0.5 micrometer and 50 micrometers is formed ammonothermally on the template substrate 1101 and _CoF2 . , as an additive to the mineralizer, and the template substrate 1101 consists of high quality GaN seed crystals. In another particular embodiment, the Co-doped exfoliation layer 1103 is deposited by MOCVD onto a template substrate 1101 (eg, a high quality GaN substrate) with cyclopentadienyl cobalt dicarbonyl ((C ₅ H ₅ )Co (CO) ₂ ), cobalt (II) acetylacetonate (Co(CH ₃ C(O)CHC(O)CH ₃ ) ₂ ), tricarbonylnitrosylcobalt (Co(CO) ₃ NO), dicobalt octacarbonyl ( Co ₂ (CO) ₈ ) and tetracobalt dodecacarbonyl (Co ₄ (CO) ₁₂ ) as dopant precursors. In yet another particular embodiment, the Co-doped exfoliation layer 1103 is deposited by hydride vapor phase epitaxy (HVPE) onto a template substrate 1101, such as a high quality GaN substrate, cyclopentadienyl cobalt dicarbonyl (( _C5H5 )Co(CO) ₂ ), cobalt (II) acetylacetonate ( _Co ( _CH3C (O)CHC(O) _CH3 ) ₂ ), tricarbonylnitrosylcobalt (Co(CO) _3NO ) , dicobalt octacarbonyl (Co ₂ (CO) ₈ ), and tetracobalt dodecacarbonyl (Co ₄ (CO) ₁₂ ) as dopant precursors. Further details are provided in US Pat. No. 8,148,801, the contents of which are hereby incorporated by reference in their entirety. In some embodiments, the exfoliation layer 1103 comprises or consists of InGaN, such that the substrate can be removed by photoelectrochemical etching techniques after fabrication of at least one device structure, for example. In some embodiments, the InGaN-containing exfoliation layer has a thickness between about 2 nanometers and about 100 nanometers, or between about 5 nanometers and about 50 nanometers. In some embodiments, the exfoliation layer has a bandgap that is less than the bandgap of absorbing layer 107 below. In certain embodiments, exfoliation layer 1103 comprises or consists of InGaN and a strained layer superlattice of GaN or AlGaN. In some embodiments, the strained layer superlattice has a higher percentage (%) of indium (In) than that of the absorber layer 107 and is grown by MOCVD on a template substrate 1101, such as a high quality GaN substrate. InGaN exfoliation layers are described in more detail in US Pat. No. 8,866,149 and US Patent Application Publication No. 2019/0088495, the contents of which are hereby incorporated by reference in their entirety. .

In some embodiments, substrate 101 consists of or includes a single crystal group III metal nitride layer 1104 bonded to or formed on a surface of template substrate 1101 . Single-crystal group III metal nitride layer 1104 may include gallium. Single crystal group III metal nitride layer 1104 may be deposited by HVPE, metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or the like. The single crystal group III metal nitride layer 1104 has a thickness between about 1 micrometer and about 100 micrometers, between about 2 micrometers and about 25 micrometers, or between about 3 micrometers and about 15 micrometers. can have In some embodiments, the single crystal group III metal nitride layer 1104 has a wurtzite crystal structure and (0001)+c-plane, (000-1)-c-plane, {10-10}m-plane, {11- 2±2}, {60-6±1}, {50-5±1}, {40-4±1}, {30-3±1}, {50-5±2}, {70-7± 3}, {20-2±1}, {30-3±2}, {40-4±3}, {50-5±4}, {10-1±1}, {10-1±2} , {10-1 ± 3}, {21-3 ± 1}, or {30-3 ± 4} within 5 degrees, within 2 degrees, within 1 degree, or within 0.5 degrees have. In some embodiments, a nucleation layer (not shown) is present at the interface between template substrate 1101 and single crystal group III metal nitride layer 1104 . In some embodiments, the nucleation layer consists of or includes one or more of aluminum nitride, gallium nitride, and zinc oxide. In some embodiments, the nucleation layer is deposited on template substrate 1101 by at least one of low temperature MOCVD, sputtering, and electron beam evaporation. In some embodiments, the nucleation layer has a thickness between about 1 nanometer and about 200 nanometers, or between about 10 nanometers and about 50 nanometers. In some embodiments, the substrate further includes one or more strain management layers, such as AlGaN layers or strained layer superlattices.

In some embodiments, the atomic impurity concentration of at least one of oxygen (O) and hydrogen (H) in large area surface 102 is greater than about 1×10 ¹⁶ cm ⁻³ or greater than about 1×10 ¹⁷ cm ⁻³ . or higher than about 1×10 ¹⁸ cm ⁻³ . In some embodiments, the ratio of the atomic impurity concentration of H to the atomic impurity concentration of O is between about 0.3 and about 2, between about 1.1 and about 1000, or between about 5 and about 100. be. In some embodiments, at least one of lithium (Li), sodium (Na), potassium (K), fluorine (F), chlorine (Cl), bromine (Br), or iodine (I) in the large area surface 102 The impurity concentration is higher than about 1×10 ¹⁵ cm ⁻³ , higher than about 1×10 ¹⁶ cm ⁻³ , higher than about 1×10 ¹⁷ cm ⁻³ , or higher than about 1×10 ¹⁸ cm ^{−3 .} taller than. In certain embodiments, the impurity concentrations of O, H, carbon (C), Na, and K in the large area surface 102 are each about between 1×10 ¹⁶ cm ⁻³ and about 1×10 ¹⁹ cm ⁻³ , between about 1×10 ¹⁶ cm ⁻³ and about 2×10 ¹⁹ cm ⁻³ , less than 1×10 ¹⁷ cm ⁻³ , 1× less than 10 ¹⁶ cm ⁻³ and less than 1×10 ¹⁶ cm ⁻³ . In other embodiments, the impurity concentrations of O, H, C, and/or Na and K in the large area surface 102, when quantified by calibrated secondary ion mass spectrometry (SIMS), are each: between about 1×10 ¹⁶ cm ⁻³ and 1×10 ¹⁹ cm ⁻³ , between about 1×10 ¹⁶ cm ⁻³ and about 2×10 ¹⁹ cm ⁻³ , less than 1×10 ¹⁷ cm ⁻³ , and It is between about 3×10 ¹⁵ cm ⁻³ and about 1×10 ¹⁸ cm ⁻³ . In still other embodiments, the impurity concentrations of O, H, C, and/or F and Cl in the large area surface 102 are each , between about 1×10 ¹⁶ cm ⁻³ and about 1×10 ¹⁹ cm ⁻³ , between about 1×10 ¹⁶ cm ⁻³ and about 2×10 ¹⁹ cm ⁻³ , less than 1×10 ¹⁷ cm ⁻³ , and between about 1×10 ¹⁵ cm ⁻³ and about 1×10 ¹⁹ cm ⁻³ . In some embodiments, the impurity concentration of H in the large area surface 102 is approximately 5×10 ¹⁷ cm ⁻³ and 1×10 ¹⁹ cm −3 as quantified by calibrated secondary ion mass spectrometry (SIMS). between ^-3 . In certain embodiments, the substrate 101 has an infrared absorption peak at about 3175 cm ⁻¹ and an absorbance per unit thickness greater than about 0.01 cm ⁻¹ .

Substrate 101 is characterized by a wurtzite structure that is substantially free of any cubic or other crystalline structures, and the other structure is less than about 0.1% by volume relative to the substantial wurtzite structure. can be

Substrate 101 has a total thickness variation (TTV) of less than about 25 microns, less than about 10 microns, less than about 5 microns, less than about 2 microns, or less than about 1 micron, and a total thickness variation (TTV) of less than about 200 microns. It can be characterized by a macroscopic curvature of less than, less than about 100 microns, less than about 50 microns, less than about 25 microns, or less than about 10 microns. Substrate 101 is less than about 2 cm ⁻² , less than about 1 cm −2 , less than about 0.5 ^{cm −2} , less than about 0.25 cm ⁻² on large area surface 102 having a diameter or feature dimension greater than about 100 microns. Alternatively, it may have a macroscopic defect density of less than about 0.1 cm ⁻² . The variation in miscut angle across the large surface 102 of the substrate 101 is less than about 5 degrees, less than about 2 degrees, less than about 1 degree, less than about 0.5 degrees, less than about 0.2 degrees for each two orthogonal crystallographic orientations. less than about 0.1 degrees, less than about 0.05 degrees, or less than about 0.025 degrees. The root mean square surface roughness of the large area surface 102 is less than about 0.5 nanometers, less than about 0.2 nanometers, less than about 0.15 nanometers when measured over an area of at least 10 μm×10 μm, It can be less than about 0.1 nanometers, or less than about 0.05 nanometers. The substrate 101 can be characterized by n-type conductivity with carrier densities between about 1×10 ¹⁷ cm ⁻³ and about 3×10 ¹⁹ cm ⁻³ and carrier mobilities greater than about 100 cm ² /Vs. In some embodiments, the substrate 101 is highly transparent and has a light absorption coefficient of less than about 10 cm ⁻¹ , less than about 5 cm ⁻¹ , less than about 2 cm ⁻¹ at a wavelength of 405 nanometers or 450 nanometers. , less than about 1 cm ⁻¹ , less than about 0.5 cm ⁻¹ , less than about 0.2 cm ⁻¹ , or less than about 0.1 cm ⁻¹ .

In one embodiment, one or more n-type first non-absorbing layers 105 comprising Al _u In _v Ga _1-uv N layers are deposited on the substrate, where 0≦u, v, u+v≦ 1. In some embodiments, the n-type first non-absorbing layer 105 is deposited immediately after depositing the single crystal group III metal nitride layer 1104, i.e., the growth process is interrupted or the substrate 101 or template substrate 1104 is deposited. It is deposited without removing it from the reactor. In some embodiments, one or more additional layers are deposited to help manage stress in the overall structure. The carrier density in the n-type first non-absorbing layer 105 can range between about 10 ¹⁶ cm ⁻³ and 10 ²⁰ cm ⁻³ . In some embodiments, silicon, germanium, or oxygen is the n-type dopant in the n-type first non-absorbing layer 105 . In some embodiments, germanium is selected as the n-type dopant. In some embodiments, the n-type carrier density in the n-type first non-absorbing layer 105 is between 5×10 ¹⁷ cm ⁻³ and 10 ²⁰ cm ⁻³ or between 2×10 ¹⁸ cm ⁻³ and 6×10 cm −3 . It ranges between ¹⁹ cm ⁻³ . A high doping level may be particularly desirable if the substrate 101 has a (0001)+c-plane orientation, as it may more effectively screen the piezoelectric field for efficient carrier collection. A high doping level may also be desirable if the template substrate 1101 is electrically insulating or highly resistive. A steep or graded composition or doping profile may be introduced at the interface within the n-type first non-absorbing layer 105 . Deposition may be performed using metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). For example, a substrate may be placed on a susceptor within an MOCVD reactor. After closing, evacuating, and backfilling the reactor, the susceptor may be heated to a temperature between about 800 and about 1350° C. in the presence of a nitrogen-containing gas. In one particular embodiment, the susceptor is heated to about 1185° C. in a stream of ammonia. Flows of gallium-containing organometallic precursors, such as trimethylgallium (TMG), triethylgallium (TEG), or triisopropylgallium, in a carrier gas at about 1 standard cubic centimeter per minute (sccm) and about 50 standard cubic centimeters per minute. (about 0.001 standard L/min and about 0.05 standard L/min). Carrier gases can include hydrogen, helium, nitrogen, or argon. The ratio of the group V precursor (ammonia) flow rate to the group III precursor (trimethylgallium, triethylgallium, trimethylindium, trimethylaluminum) flow rate during growth is between about 2000 and about 12000. A flow of disilane in the carrier gas can be initiated at a total flow rate of between about 0.1 and 10 sccm (about 0.0001 and about 0.01 standard L/min). In some embodiments, the doping is performed by adding one or more of _SiH4 , _Si2H6 , _{SiH2Cl2 , SiHCl3} , _SiCl4 , _GeH4 , _{GeCl4 , O2} , and _H2O to the admitted gas. This is achieved by adding In some embodiments, one or more of the n-type first non-absorbing layer 105 and second non-absorbing layer 109 are metamorphic buffer layers to easily accommodate lattice constant differences between the layers. In some embodiments, the doping level of the n-type first non-absorbing layer 105 can be non-uniform, having two or more levels of doping and/or a graded doping level. In one embodiment, the substrate temperature is varied during deposition of the n-type first non-absorbing layer 105 . In one embodiment, the substrate temperature is held at a high value, eg, between 1100 and 1350° C., for the first portion of the n-type first non-absorbing layer 105 and then the n-type first A second portion of the non-absorbing layer 105 is lowered to a lower temperature, eg, the same temperature at which the absorbing layer 107 is deposited, eg, between about 700 and about 950°C. In some embodiments, the thickness of the second portion of n-type first non-absorbing layer 105 is between about 1 nanometer and about 20 nanometers.

After forming the n-type first non-absorbing layer 105 to a predetermined thickness for a predetermined time, the absorbing layer 107 is formed. In one embodiment, absorber layer 107 is deposited by MOCVD at a substrate temperature between about 700 and about 950 degrees Celsius. Indium can be added to absorber layer 107 by using at least one of trimethylindium (TMIn), triethylindium (TEIn), and triisopropylindium as precursors in MOCVD. The deposition rate of the absorbing layer 107 is between about 0.005 and about 1 nanometers per second, or between about 0.01 and about 0.5 nanometers per second, or between about 0.02 and about 0.5 nanometers per second. It can be chosen to be between 2 nanometers. In some embodiments, absorbing layer 107 is unintentionally doped. In some embodiments, absorber layer 107 uses oxygen, silicon, or germanium as a dopant with a dopant concentration between about 5×10 ¹⁵ cm ⁻³ and about 5×10 ¹⁹ cm ⁻³ , or about It is n-type doped between 5×10 ¹⁶ cm ⁻³ and about 5×10 ¹⁸ cm ⁻³ . In some embodiments, absorbing layer 107 uses Mg as a dopant with a dopant concentration between about 5×10 ¹⁵ cm ⁻³ and about 5×10 ¹⁹ cm ⁻³ , or about 5×10 ¹⁶ cm ^{−3 . 3} and about 5×10 ¹⁸ cm ⁻³ are p-type doped. In some embodiments, absorbing layer 107 has a bandgap wavelength between about 400 nanometers and about 550 nanometers, such as a bandgap wavelength between about 440 nanometers and about 500 nanometers. Absorbing layer 107 may include a single quantum well or multiple quantum wells (not shown) having 2-50 quantum wells. In some embodiments, absorber layer 107 includes between about 10 and about 30 quantum wells. Quantum wells may include InGaN well layers and GaN barrier layers. In another embodiment, the quantum wells are each _AlwInx , such that the bandgap _of the well layers is smaller than the bandgap of the barrier layers and the n-type first non-absorbing layer 105 and second non-absorbing layer 109. Ga _1-w-x N well layers and Al _y In _z Ga _1-y-z N barrier layers, where 0≦w, x, y, z, w+x, y+z≦1 and w< u, y and/or x>v, z. The well layer and barrier layer can each have a thickness between about 0.5 nanometers and about 20 nanometers. In some embodiments, the barrier layer is between about 1 nanometer and about 3 nanometers, between about 3 nanometers and about 5 nanometers, between about 5 nanometers and 10 nanometers, or about 10 nanometers. and 15 nanometers. In some embodiments, the well layer has a thickness of between 0.5 nanometers and about 1.5 nanometers, between about 1.5 nanometers and about 2.5 nanometers, between about 2.5 nanometers and about 3.5 nanometers. It has a thickness of between 5 nanometers, between about 3.5 nanometers and about 4.5 nanometers, or between about 4.5 nanometers and about 10 nanometers. In other embodiments, the absorber layer 107 comprises or consists of a double heterostructure, and the InGaN _{or AlwInxGa1 -w-xN} layer with a thickness of about 20 nm to about 500 nm is GaN or _Aly Surrounded by In _z Ga _1-yz N layers, where w<u,y and/or x>v,z. In certain embodiments, the thickness of the double heterostructure is between about 10 nanometers and about 25 nanometers, between about 25 nanometers and about 40 nanometers, between about 40 nanometers and about 60 nanometers, Between about 60 nanometers and about 100 nanometers, between about 100 nanometers and about 200 nanometers, or thicker than about 200 nanometers. A steep or graded composition or doping profile may be introduced at the interface within absorber layer 107 . The composition and structure of the active layer are selected to absorb light at a preselected wavelength, such as 405 nanometers or 450 nanometers, for example. In some embodiments, the wavelength is selected to be between about 400 nanometers and about 500 nanometers. Absorbing layer 107 may be characterized by photoluminescence spectroscopy. In some embodiments, the composition of the absorbing layer 107 is such that the photoluminescence spectrum is between 5 and 50 nanometers longer than the desired absorption wavelength of the photodiode structure 1000, or between 10 and 25 nanometers. The length is between meters and is chosen to have a long wavelength peak. In some embodiments, the quality and layer thickness within the absorbing layer 107 is characterized by X-ray diffraction.

In some embodiments, one or more optional second non-absorbing layers 109 are then deposited. the second non-absorbing layer 109 comprises Al _s In _t Ga _1-s−t N, where 0≦s, t, s+t≦1 and has a higher bandgap than the absorbing layer 107; It can be p-type doped or unintentionally doped. In one particular embodiment, second non-absorbing layer 109 comprises AlGaN. In another embodiment, the second non-absorbing layer 109 comprises an AlGaN/GaN multiple quantum barrier (MQB), which comprises layers of AlGaN and GaN each having a thickness between about 0.2 nm and about 5 nm. Include alternately. In some embodiments, the one or more second non-absorbing layers 109 are metamorphic buffer layers to facilitate accommodating lattice constant differences between the layers of the photodiode structure 1000 . A steep or graded composition or doping profile may be introduced at the interface within the second non-absorbing layer 109 . In some embodiments, the optical design of second non-absorbing layer 109 is adjusted to achieve a light reflection of greater than about 70% of light transmitted through absorbing layer 107 from the substrate.

Next, a p-type layer or a p-type non-absorbing layer 111 made of Al _q In _r Ga _1-qr N is placed on the absorbing layer 107, and if there is a second non-absorbing layer 109, is deposited thereon, where 0≤q, r, q+r≤1. P-type layer 111 is doped with Mg to a level between about 10 ¹⁶ cm ⁻³ and 10 ²¹ cm ⁻³ , between about 5 nanometers and about 1 micrometer, between about 20 nanometers and about 400 nanometers. or between about 100 nanometers and about 250 nanometers. In some embodiments, the Mg concentration of p-type layer 111 closest to absorber layer 107 is between 10 ¹⁸ cm ⁻³ and 10 ²¹ cm ⁻³ , between 3×10 ¹⁸ cm ⁻³ and 3×10 ²⁰ cm ^{−3 .} between 10 ¹⁹ cm ⁻³ and 2×10 ²⁰ cm ⁻³ . A high doping level may be particularly desirable if the substrate 101 has a (0001)+c-plane orientation, as it may more effectively screen the piezoelectric field for efficient carrier collection. The outermost 1-30 nanometers of p-type layer 111 may be more doped than other portions of p-type layer 111 to allow improved electrical connection. In some embodiments, the substrate temperature is varied during the deposition of p-type layer 111 . In some embodiments, the substrate temperature is the same as the temperature at which the absorber layer 107 is deposited, such as between about 700 and about 950° C., for the first portion of the p-type layer 111 . retained. The substrate temperature is then raised to a high level, eg, between about 750 and about 1000° C., for the second portion of p-type layer 111 . In some embodiments, the thickness of the first portion of p-type layer 111 is between about 1 nanometer and about 20 nanometers, or between about 20 nanometers and 40 nanometers.

In certain embodiments, a tunnel junction and other n-type layers (not shown) are deposited on top of p-type layer 111 . In some embodiments, one or more additional non-absorbing layers and additional absorbing layers are deposited over the tunnel junction.

comprising an n-type first non-absorbing layer 105, an absorbing layer 107, one or more optional second non-absorbing layers 109, a p-type layer 111, further absorbing layers, one or more n-type cladding layers, and the semiconductor layer, which may also include one or more p-type cladding layers, is the same as or within about 2 degrees, within about 1 degree, or within about 0.5 degrees of the crystal orientation of large surface 102 of substrate 101 , have a very high crystalline quality, contain nitrogen, and have a surface dislocation density of less than 10 ⁹ cm ⁻² . The semiconductor layer is less than 10 ¹⁰ cm ⁻² , less than 10 ⁹ cm ⁻² , less than 10 ⁸ cm ⁻² , less than 10 ⁷ cm ⁻² , less than 10 ⁶ cm −2 , less than 10 ⁵ cm ⁻² , ^{10 4} cm ^{−2 .} It may have a surface dislocation density of less than ² , less than 10 ³ cm ⁻² , or less than 10 ² cm ⁻² . In some embodiments, the semiconductor layer is substantially transparent and has a light absorption coefficient of less than 100 cm ⁻¹ , less than 50 cm ⁻¹ , or less than 5 cm ⁻¹ at wavelengths between about 400 nm and about 3077 nm, and about at wavelengths between 3333 nm and about 6667 nm.

In certain embodiments, the semiconductor layer is oriented within 5 degrees of the m-plane and the FWHM of the 1-100 X-ray rocking curve of the top surface is less than 300 arcsec, less than 100 arcsec, or 50 arcsec. is less than In certain other embodiments, the semiconductor layer has an orientation within 5 degrees of the a-plane and the FWHM of the 11-20 X-ray rocking curve of the top surface is less than 300 arcsec, less than 100 arcsec, or 50 arcsec. less than an arc second. In still other specific embodiments, the semiconductor layer is {1-10±1}, {1-10±2}, {1-10±3}, {20-2±1}, {30-3± 1}, or an orientation within 5 degrees of a semipolar orientation selected from {11-2±2}, and the FWHM of the lowest order semipolar symmetrical X-ray rocking curve of the top surface is less than 300 arcseconds; Less than 100 arc seconds or less than 50 arc seconds. In certain other embodiments, the semiconductor layer has an orientation within 5 degrees of the (0001) c-plane and the FWHM of the 0002 X-ray rocking curve for the top surface is less than 300 arcsec, less than 100 arcsec, or Less than 50 arc seconds. In still other particular embodiments, the semiconductor layer has an orientation within 10 degrees of the (000-1) c-plane and the FWHM of the 0002 X-ray rocking curve for the top surface is less than 300 arcsec and less than 100 arcsec. , or less than 50 arcseconds.

In some embodiments, fabrication of structures that omit one or more of such layers may be useful for process development. The p-type layer 111 and absorber layer 107 may be omitted, for example, to develop or optimize the p-side reflective electrical connection 113, as described below. To exploit or optimize the electrical, optical and material properties of absorbing layer 107, one or more of p-side reflective electrical connection 113 and p-type layer 111 may be omitted.

Crystallographic orientation, as well as doping and bandgap profiles of semiconductor layers can significantly affect the performance of photodiodes, including one or more of photodiode structures, photodiode dies, or packaged photodiodes. For +c-plane GaN-based devices containing heterostructures, the strong polarity of the GaN bonds and the spontaneous and piezoelectric polarization due to the lack of inversion symmetry in the wurtzite crystal structure can lead to strong electric fields and undesired device performance. is well known. It is believed that these electric fields can adversely affect photodiode performance, especially at high current densities, and several approaches to addressing these effects are identified and disclosed herein.

When a +c-plane substrate is used, that is, when the crystal orientation is within 5 degrees, within 2 degrees, within 1 degree, or within 0.5 degrees from (0001), for high-power photodiodes, 1) large-area 2) the epitaxial growth conditions are well established and stable; and 3) the dopant concentration is relatively easy to control over many orders of magnitude. has several advantages, including being However, as shown in the comparative examples below, the use of relatively standard LED-type structures may not allow photodiodes with high fill factors.

In certain embodiments, the adverse effects of spontaneous and piezoelectric fields in +c-plane photodiodes are exacerbated with increasing indium (In) percent in absorber layer 107, while high doping levels on both the n-side and p-side of absorber layer 107 is reduced by using The effects of bandgap alignment and spontaneous and piezoelectric fields on photodiode performance at high current densities were investigated. The semiconductor layers used to analyze the performance of the photodiode structure 1000 of the photodiode die are shown schematically in FIG. In a simplified model, absorber layer 730 is placed between n-type doped layer 710 and p-type doped layer 750 . Optionally, an n-type non-absorbing layer (or cladding layer) 720 may be placed between the n-type doped layer 710 and the absorbing layer 730 . Optionally, a p-type non-absorbing layer (or cladding layer) 740 is disposed between the absorbing layer 730 and the p-type doped layer 750 . For simplicity of explanation, the absorber layer 730 is modeled as a double heterostructure with a thickness of 40 nanometers; are expected to have similar effects.

Absorbing layers 730 comprising one or more layers comprising In _0.18 Ga _0.82 N adequately absorb light having wavelengths of about 473 nanometers or less, but short circuit as shown in FIG. 8A. The current and fill factor are 2.0×10 ¹⁹ cm ⁻³ doping level of n-type doped layer 710 in contact with the first side of absorber layer 730 and p-type in contact with the second side of absorber layer 730 . It is very low when the doping level of doped layer 750 is 2.0×10 ¹⁹ cm ⁻³ . As shown in FIG. 8B, this very poor performance is believed to be due to poor screening of the electric field with respect to the polarization discontinuity and the band offset between InGaN and GaN. However, the doping level of the n-type doped layer 710 contacting the first side of the absorbing layer 730 is increased to 3.5×10 ¹⁹ cm ⁻³ and the p-type doped layer contacting the second side of the absorbing layer 730 is Increasing the doping level of 750 to 6.0×10 ²⁰ cm ⁻³ greatly improves the IV performance when illuminated as shown in FIG. 9A. This significant improvement in performance is due to the very effective screening of the electric field at the absorber layer 730 and in close proximity to the GaN-InGaN interface, as shown in FIG. 9B. As shown in the table of FIG. 15, increasing the doping level in both layers in contact with the absorbing layer 730 can improve the fill factor FF. In particular, a fill factor of greater than 90% is required in n-type doped layer 710, or in n-type non-absorbing layer 720, if present, with a doping concentration of about 3.5×10 ¹⁹ cm ⁻³ or higher; , in p-type doped layer 750, or in p-type non-absorbing layer 740, if present, by an active doping level of about 2.0×10 ²⁰ cm ⁻³ or higher.

Referring back to FIG. 1, in some embodiments, the photodiode structure 1000 includes an n-type first non-absorbing layer 105, at least one absorbing layer 107, and a p-type layer 111, each 10 It has a threading dislocation density of less than ⁷ cm ⁻² . The photodiode structure 1000 also includes one or more absorbing layers 107, an n-type first non-absorbing layer 105, and a p-type layer 111, which are oriented 2 degrees and 5 degrees from the (000-1)-c plane. Angles between degrees can have different crystallographic orientations. Photodiode structure 1000 also includes one or more absorbing layers 107, n-type first non-absorbing layer 105, and p-type layer 111, which are crystalline within 5 degrees of the {10-10}m plane. Orientated, n-type first non-absorbing layer 105 and p-type layer 111 are each characterized by having a dopant concentration of at least 4×10 ¹⁸ cm ⁻³ . The photodiode structure 1000 also includes one or more absorbing layers 107, an n-type first non-absorbing layer 105, and a p-type layer 111, which are {10-1-2}, {10-1- 1}, {20-2-1}, {30-3-1}, and {40-4-1} with a crystal orientation within 5 degrees from a semipolar plane selected from n-type primary The non-absorbing layer 105 and the p-type layer 111 of are each characterized by having a dopant concentration of at least 2×10 ¹⁸ cm ⁻³ .

FIG. 15 contains the illuminated IV performance of an InGaN/GaN photodiode having the structure outlined in FIG. For ease of illustration, the absorber layer is modeled as a 40 nm thick double heterostructure.

_a first surface of absorbing layer 730 _and The doping level of the contacting n-type doped layer 710, or in the n-type cladding layer 720, if present, is 2.0×10 ¹⁹ cm ⁻³ and is in contact with the second side of the absorbing layer 730. At a doping level of 8.0×10 ¹⁸ cm ⁻³ in p-type doped layer 750 , or in p-type cladding layer 740 if present, the fill factor is less than 60%. However, the doping level of p-type doped layer 750 in contact with the second side of absorber layer 730, or in p-type cladding layer 740, if present, is increased to 2.0×10 ¹⁹ cm ⁻³ . , the fill factor increases to about 80%, and the doping of p-type doped layer 750 in contact with the second side of absorber layer 730, or of p-type cladding layer 740, if present. Further increasing the level to 1.0×10 ²⁰ cm ⁻³ increases the fill factor to about 93%. The results tabulated in FIG. 15 show that reducing the doping level of the p-type cladding layer 740 adjacent to the absorber layer 730 relative to the doping level of the p-type doped layer 750 significantly reduces the fill factor. ing. It is difficult to continue to achieve complete doping until the deposition of the undoped absorber layer 730, so we can see an abrupt change in doping profile from the undoped absorber layer 730 deposited at temperatures below 950° C. to much higher temperatures. This result is important because it can occur as soon as deposited and turned into p-type doped layer 750 with the desired doping level. However, as also shown in the table of FIG. 15, the fill factor FF is the n-type side and p-type side of the absorber layer 730, respectively. In particular, the p-type cladding layer 740 has an indium concentration intermediate that of the absorber layer 730 and the indium concentration of the n-type doped layer 710 and/or the p-type doped layer 750 by introducing into one or both of can be improved if it has The indium concentration in the middle of the cladding layer can be uniform, have a continuous gradient, or have a stepped gradient. The n-type cladding layer 740 may comprise a strained layer superlattice. In some embodiments, photodiode structure 1000 includes at least one of an n-type cladding layer and a p-type cladding layer, wherein n-type cladding layer 720 comprises n-type doped layer 710 and one or more absorbing layers. Located between layers 730, n-type cladding layer 720 has a dopant concentration of at least 2×10 ¹⁹ cm ⁻³ and p-type cladding layer 740 is p-type doped with one or more absorber layers 730 . Located between layers 750, p-type cladding layer 740 has a dopant concentration of at least 5×10 ¹⁹ cm ⁻³ .

In some embodiments, the adverse effects of spontaneous and piezoelectric fields in +c-plane oriented photodiodes are within 6 degrees, within 5 degrees, within 4 degrees, within 3 degrees, within 2 degrees, or within 1 degree from (000-1). It is reduced by using a −c-plane substrate having a crystal orientation within 10 degrees, such as within 10 degrees. In some embodiments, the substrate and the semiconductor layer have crystallographic orientations that differ from (000-1) by an angle between 1 and 10 degrees, or between 2 and 5 degrees. In some embodiments, the substrate and semiconductor layers are oriented differently, from the (000-1) toward the <10-10>m direction. In some embodiments, the substrate and semiconductor layers are oriented differently, from the (000-1) toward the <11-20>a direction. Referring again to the table of FIG. 15, 1.0×10 ¹⁶ cm ⁻³ or 1.0×10 ¹⁷ cm ⁻³ or 1.0 at the n-type doped and p-type doped layers immediately adjacent absorber layer 730 . A doping concentration of ×10 ¹⁸ cm ⁻³ was found to be sufficient to achieve a high fill factor for both 12% and 18% indium concentrations in absorber layer 730 . The doping concentration of n-type doped layer 710 and p-type doped layer 750 is 1.0×10 ¹⁶ cm ⁻ for absorber indium concentrations higher than 8% when the substrate and semiconductor layers each have a −c crystal orientation. It is believed that fill factors higher than 85% can be achieved for cases between ³ and 1.0×10 ²⁰ cm ⁻³ . In one example, the photodiode is characterized by a fill factor of at least 50% under light illumination level conditions that produce a current density of at least 10 Acm ⁻² .

In some embodiments, the adverse effects of spontaneous and piezoelectric fields in +c-plane photodiodes are reduced to within 5 degrees, within 2 degrees, within 1 degree, or within 0.5 It is alleviated by using a substrate having an orientation within degrees. Referring again to the table of FIG. 15, at the n-type doped layer 710 immediately adjacent to the absorber layer, or at the n-type cladding layer 720, if present, as well as at the p-type doped layer 750, or p If the mold cladding layer 740 is present, a doping concentration of 2.0×10 ¹⁹ cm ⁻³ therein provides a fill factor of greater than 90% for both 12% and 18% indium concentrations in the absorber layer. It has been found to be sufficient to implement

In some embodiments, the adverse effects of spontaneous and piezoelectric fields in +c-plane photodiodes are within 5 degrees, within 2 degrees, within 1 degree, or within 0.5 degrees from {20-2-1} or {30-3-1}. It is alleviated by using a semi-polar substrate having a crystal orientation within 5 degrees. Referring again to the table of FIG. 15, the doping concentration of 8.0×10 ¹⁸ cm ⁻³ in the n-type doped and p-type doped layers immediately adjacent to the absorber layer is both 12% and 18% of the absorber layer. was found to be sufficient to achieve a fill factor of greater than about 90%.

In some embodiments, triethylgallium (TEG) and triethylindium (TEIn) are used instead of conventional trimethylgallium (TMG) and trimethylindium (TMIn) to reduce the carbon content of N-polar or semipolar InGaN layers. It is used as an organometallic precursor. For example, the carbon concentration of the semiconductor layer is less than 1×10 ¹⁸ cm ⁻³ or less than 1×10 ¹⁷ cm ⁻³ . In some embodiments, the hydrogen ( _H2 ) to nitrogen ( _N2 ) carrier gas ratio, substrate temperature, and pressure are optimized to minimize hillock formation in the N-polar semiconductor layer.

In some embodiments, the semiconductor layer is annealed to electrically activate the p-type dopants. In one embodiment, the annealing is performed in situ in the MOCVD reactor used to deposit the semiconductor layer, for example, by heating to a temperature between about 500° C. and about 900° C. in flowing _N2 . . In certain embodiments, annealing is performed in a furnace or in a rapid thermal annealing (RTA) furnace, for example, in a _N2 flow, heating to a temperature between about 400°C and about 900°C. In some embodiments, the atmosphere during the annealing process may also contain an oxidizing gas such as _O2 . In some embodiments, the percentage of oxidizing gas in the annealing atmosphere is between about 5% and about 95%. In some embodiments, the duration of the annealing treatment is between about 1 second and about 5 hours, or between about 10 seconds and about 1 hour. In some embodiments, after annealing, the surface of the semiconductor layer is cleaned and prepared for further deposition. In some embodiments, the cleaning treatment is one or more of treatment with inorganic acids such as hydrochloric acid, nitric acid, or aqua regia, piranha etching, buffered oxide etching, dry etching, or treatment with plasma, such as argon plasma. comprising or consisting of

In some embodiments, a transparent conductor layer is deposited over the p-type semiconductor layer. In some embodiments, the transparent conductor layer comprises a transparent conductive oxide (TCO) such as indium tin oxide or aluminum zinc oxide. In some embodiments, the transparent conductor layer is deposited by one or more of thermal evaporation, electron beam evaporation, and sputtering. In one embodiment, the deposited TCO layer is annealed at a temperature between about 300 and 700° C. in a controlled atmosphere containing oxygen to improve both the optical/transparency and electrical properties of the TCO layer. Optimize. In some embodiments, the transparent conductor layer has a thickness between about 10 nanometers and about 1000 nanometers.

Each photodiode structure 1000 of the present disclosure is intended for use in a photodiode die 1002 of a packaged photodiode having multi-reflecting features. A packaged photodiode includes a photodiode die 1002 and may consist of a heat sink, housing, separate photodetector, optical entrance aperture, solder bumps, wire joints, or a polymer such as epoxy or silicone. , may also include one or more of the encapsulations containing it. In some embodiments, the packaged photodiode further includes one or more elements for coupling light to and from the photodiode die 1002 and for enabling additional reflection. can contain

To maximize the efficiency of the packaged photodiode, it can be important to maximize the reflectivity of the front and back surfaces of the photodiode structure 1000 of the photodiode die 1002 . The photodiode die 1002 is generally singulated or diced into a photodiode structure including one or more non-absorbing layers 105, 109, an absorbing layer 107, a p-side reflective electrical connection 113 and an n-side reflective electrical connection 114. From the object 1000, individual sized objects (eg, rectangular pieces) are cut. Photodiode die 1002 consists of or includes a device cavity region, which includes at least one of a substrate and a light transmissive member, and may be bounded by edge structures such as optical windows and reflective films. A device cavity region is formed from at least two opposing reflective members and a light transmissive member between the two opposing reflective members. Electromagnetic waves that enter the device cavity region through the optical window pass through the light transmissive member and are internally reflected at least twice between the reflective members. Light emitted from one or more absorbing layers may also be internally reflected at least twice between the reflective members.

In some embodiments, the two opposing faces are parallel to each other. In some other embodiments, the two opposing surfaces are not parallel to each other. In the photodiode structure 1000 shown in FIG. 1, the light transmitting member is the substrate 101, and the reflecting members are the p-side reflective electrical connection 113 and the n-side reflective electrical connection 114, as will be described later.

Furthermore, in order to maximize the efficiency of the packaged photodiode, it is important to minimize the electrical resistance of the connections of the photodiode structure. Referring again to FIG. 1, a p-side reflective electrical connection 113 may be deposited over the p-type layer 111 . In preferred embodiments, the average reflectivity of the p-side reflective electrical connection is greater than 70%, greater than 80%, or greater than 85% at a particular angle or range of angles at which light is incident during operation. , greater than 90%, greater than 95%, greater than 97%, or greater than 98%. In general, the term "average reflectance," as used herein, is the angle representative of the range of angles of incidence during device operation at a particular wavelength between 390 and 460 nanometers. It is intended to broadly describe reflectance values calculated by averaging at least two reflectance measurement data points of a surface at one or more angles to the surface of the layer. During operation of the packaged photodiode, in some embodiments, light (or optical radiation) is coupled to the vertical edges, or nearly vertical edges, of the photodiode die 1002, The angle of incidence inside the reflective layer (e.g., p-side reflective electrical connection 113 or n-side reflective electrical connection 114 in FIGS. 1 and 2) is in the plane of the reflective layer (e.g., large area surface 102 in FIG. 2). between about 0 and about 30 degrees, between about 0.2 and about 20 degrees, or between about 0.3 and about 10 degrees, when measured from parallel planes). In one example, the light-receiving surface 252 shown in FIG. is oriented as the vertical plane of In some embodiments of the photodiode die 1002, light is coupled into the non-perpendicular edge of the photodiode die 1002 and the angle of incidence inside the reflective layer is approximately Between 0.1 and about 60 degrees, between about 0.2 and about 40 degrees, or between about 0.3 and about 20 degrees. In other embodiments of photodiode die 1002, light is coupled through an aperture to a large area surface of photodiode die 1002, and the angle of incidence inside the reflective layer is in the plane of the reflective layer (e.g., in FIG. 2). between about 30 and 90 degrees, between about 45 and 90 degrees, or between about 60 and 90 degrees measured from a plane parallel to the large area surface 102). In yet another embodiment of the photodiode die 1002, light is coupled through an aperture into the large area side of the photodiode die 1002 and internally reflected at an oblique angle such that the angle of incidence inside the reflective layer is reflected Between about 0.1 and about 45 degrees, between about 0.3 and about 30 degrees, or between about 0.5 and about 20 degrees, as measured from the plane of the layer. The connection resistance of the p-side reflective electrical connection is less than 3×10 ⁻³ Ωcm ² , less than 1×10 ⁻³ Ωcm ² , less than 5×10 ⁻⁴ Ωcm ² , less than 2×10 ⁻⁴ Ωcm ² , 10 ⁻⁴ less than Ωcm ² , less than 5×10 ⁻⁵ Ωcm ² , less than 2×10 ⁻⁵ Ωcm ² , or less than 10 ⁻⁵ Ωcm ² . In preferred embodiments, the connection resistance is less than 1×10 ⁻⁴ Ωcm ² . The p-side reflective electrical connection can include at least one of silver, gold, aluminum, nickel, platinum, rhodium, palladium, titanium, chromium, germanium, ruthenium, magnesium, scandium, and the like. In some embodiments, the p-side reflective electrical connection comprises or consists of at least two layers, the first layer providing a good electrical connection and comprising platinum, nickel, aluminum, or titanium. and has a thickness between 0.1 and 5 nanometers, the second layer provides excellent optical reflectivity and includes silver, gold, or nickel, between 0.4 nanometers and 1 It has a thickness between micrometers. In some embodiments, the p-side reflective electrical connection can comprise or consist of at least 3 layers, at least 4 layers, or at least 5 layers. In some embodiments, the p-side reflective electrical connection includes three layers, a first layer comprising silver and having a thickness between about 1 nanometer and about 200 nanometers, a second layer comprises a metal with moderate affinity for oxygen and has a thickness of between about 0.5 nanometers and about 2 nanometers, and a third layer comprises silver and has a thickness of between about 50 nanometers and about 200 It has a thickness between nanometers. In some embodiments, the metal with moderate affinity for oxygen comprises or consists of nickel. In some embodiments, the metal with moderate affinity for oxygen comprises or consists of one or more of copper, cobalt, iron, and manganese. In some embodiments, the p-side reflective electrical connection is annealed after deposition to improve reflectivity and/or reduce connection resistance. In some embodiments, annealing is performed in a rapid thermal annealing (RTA) furnace heated to a temperature between about 300°C and about 1000°C. In some embodiments, the p-side reflective electrical connection reduces oxygen between about 0.1 Torr (about 13.3 Pa) and about 200 Torr (about 26664.5 Pa) to a temperature between about 500 and about 900°C. Heated in a controlled atmosphere containing at pressure to cause interdiffusion between metals with moderate oxygen affinity and silver to introduce a controlled concentration of oxygen atoms into the p-side reflective electrical contact layer. In a preferred embodiment, prior to cooling the p-side reflective electrical connection to a temperature below about 250° C., the partial pressure of oxygen is reduced to below about 10 ⁻⁴ Torr (about 0.01 Pa) to prevent excessive oxidation. Avoid silver formation. In some embodiments, the p-side reflective electrical connection includes oxygen at a maximum local concentration between about 1×10 ²⁰ cm ⁻³ and about 7×10 ²⁰ cm ⁻³ . Further details are provided in US Pat. No. 9,917,227, the contents of which are incorporated herein by reference in their entirety. The p-side reflective electrical connection can be deposited by thermal evaporation, e-beam evaporation, sputtering, or other suitable technique. In a preferred embodiment, the p-side reflective electrical connection serves as the p-side electrode of the power photodiode. In some embodiments, the p-side reflective electrical connection is flat and parallel to the semiconductor layer, which can be useful for maximizing reflectivity. In an alternative embodiment, the p-side reflective electrical connection is patterned or textured, which can be useful to bring light in and out, for example, within an aperture.

In some embodiments, the reflectance of a particular reflective surface may be measured by providing at least two types of samples, one with the reflective surface intact and one with the reflective surface removed. Both samples were measured so that the measurement probe light was incident through a first surface with low reflectance, reflected and refracted from a second surface corresponding to the reflecting surface to be measured, and had low internal reflectance through a second surface. It can be made to emit through three surfaces. In some embodiments, by using a dielectric antireflection coating tuned to the wavelength of the probe light having a wavelength similar to that used during operation of the power photodiode device, the to minimize the reflection of By fabricating the sample such that light is transmitted through the first and third surfaces at near normal incidence, reflections at the first and third surfaces can be further reduced. The optical power transmitted from the surface corresponding to the reflective surface and the third surface is measured for both types of samples and used to calculate the reflectance of the reflective surface by methods known in the art.

Referring again to FIG. 1, in one embodiment, an n-side reflective electrical connection 114 having an average reflectivity greater than about 70% is deposited on the rear surface of substrate 101 . In preferred embodiments, the average reflectivity of the n-side reflective electrical connection is greater than 80%, greater than 85%, or greater than 90% at a particular angle or range of angles at which light is incident during operation. , greater than 95%, greater than 97%, or greater than 98%. The connection resistance of the n-side reflective electrical connection is less than 1×10 ⁻³ Ωcm ² , less than 5×10 ⁻⁴ Ωcm ² , less than 2×10 ⁻⁴ Ωcm ^{2 ,} less than 10 ⁻⁴ Ωcm ² , 5×10 ⁻⁵ less than Ωcm ² , less than 2×10 ⁻⁵ Ωcm ² , or less than 10 ⁻⁵ Ωcm ² . In preferred embodiments, the connection resistance is less than 5×10 ⁻⁵ Ωcm ² . The n-side reflective electrical connection can include at least one of silver, gold, aluminum, nickel, platinum, rhodium, palladium, titanium, chromium, and the like. In some embodiments, the n-side reflective electrical connection comprises or consists of at least two layers, a first layer providing an excellent electrical connection, comprising aluminum or titanium, and comprising:0. Having a thickness between 1 and 5 nanometers, the second layer provides excellent optical reflectivity and contains aluminum, nickel, platinum, gold or silver, 10 nanometers and 10 micrometers. has a thickness between In some embodiments, the n-side reflective electrical connection comprises or consists of at least 3 layers, at least 4 layers, or at least 5 layers and has reflectivity (maximum), connection resistance (minimum ), and robustness (maximized) can be optimized together. The n-side reflective electrical connection can be deposited by thermal evaporation, e-beam evaporation, sputtering, or other suitable technique. In some embodiments, the n-side reflective electrical connection serves as the n-side electrode of the power photodiode. In some embodiments, the n-side reflective electrical connection is flat and aligned parallel to the semiconductor layer, which can be useful for maximizing reflective power. In an alternative embodiment, the n-side reflective electrical connection is patterned or textured, which can be useful to bring light in and out, for example, within an aperture.

In some embodiments, particularly in embodiments where the n-side reflective electrical connection comprises aluminum, the backside of substrate 101 is exposed to a chlorine-containing gas or plasma to reduce the contact resistance of the n-side reflective electrical connection. Process by reactive ion etching (RIE). In one particular embodiment, the chlorine-containing gas or plasma comprises _SiCl4 . In some embodiments, an additional cleaning step is performed to reduce the connection resistance of the n-side reflective electrical connection. In some embodiments, the further cleaning step includes one or more of treatment with an inorganic acid such as hydrochloric acid, nitric acid, or aqua regia, a buffered oxide etch, a dry etch, or treatment with a plasma such as an argon plasma. Contain or consist of.

In some embodiments, as shown in FIG. 2, the p-side reflective electrical connection includes a two-part mirror/p-electrode that includes a discrete p-electrode 215 and a discrete p-electrode 215 element. It includes a p-side reflective electrical connection 113, shown as a p-side reflective electrical connection layer deposited thereon. The discontinuous p-electrode 215 is optimized as an electrical connection and is fabricated, for example, as a nickel/gold or platinum/gold laminate, where the nickel or platinum is approximately 20 to 200 nm thick, Gold is about 100 nm to 1 micrometer thick. In one suitable embodiment, the discontinuous p-electrode 215 is a grid electrode with grid openings of between about 1 micrometer and 0.1 cm on each side. The p-side reflective electrical connection 113 contains at least one of silver, gold, aluminum, platinum, rhodium, palladium, chromium, etc., and is formed on the p-type layer 111 and on the grid-like discontinuous p-electrode 215 . can be coated. Preferably, the p-side reflective electrical connection is deposited after any annealing treatment to the discontinuous p-electrode to reduce interdiffusion. Optionally nickel, rhodium, platinum, palladium, iridium, ruthenium, rhenium, tungsten, molybdenum, niobium, tantalum, or MC _x N _y O _z where M is aluminum, boron, silicon, titanium, vanadium, chromium , yttrium, zirconium, lanthanum, or a metal element such as a rare earth metal, where x, y, and z are each between 0 and 3) are formed between the discontinuous p-electrode 215 and the p-side It is arranged between the reflective electrical connections 113 . The operating current density is 10 A/cm ² and the sheet resistance for the p-type layer is 4×10 ⁵ Ω/sq. Assuming no direct conduction to the reflected electrical connection 113, the percent power loss due to lateral conduction in the p-type layer is approximately 0.6 for grating finger spacings of 2, 5, and 10 microns, respectively. , 3.6, and 14.5%. The discontinuous p-electrodes 215 may instead be arranged in an array of dots, rectangles, circles, etc. in a plane parallel to the large area surface 102 rather than in a grid configuration. Preferably, the discontinuous p-electrodes 215 are spaced from each other by between about 1 micrometer and 0.1 cm. Using a reflective metal p-electrode, or a combination of a reflective electrical connection and a discontinuous electrode, large area power photodiodes can be fabricated without the need for lateral carrier transport over long distances through the p-doped layer , thus minimizing the lateral ohmic losses and series resistance of the device. Parasitic light absorption by the discontinuous p-electrode can be minimized by designing the electrode pattern and orienting the light propagation path so that light is primarily incident on the discontinuous p-electrode pattern.

The photodiode structure includes a p-side reflective electrical connection disposed over the p-type layer, the p-side reflective electrical connection being 390 nanometers at a particular angle or range of angles at which light is incident during operation. and 460 nanometers, and have an average reflectance of at least 80% and a junction resistance of less than 1×10 ⁻³ Ωcm ² .

As noted above, the photodiode structure 1000 of the present disclosure is intended for use in photodiode dies and packaged photodiodes having multi-reflection geometries. In some embodiments, during operation, a photodiode die disposed within a packaged photodiode receives radiation of one or more wavelengths, also referred to herein as light, from light illumination source 251. configured to Light illumination source 251 may include a laser, optical fiber, or other useful radiation source. To optimize the power efficiency of packaged photodiodes, it is important to maximize the reflectivity of the front and back surfaces of the photodiode dies, as well as the sides of individual photodiode dies after singulation. is. In addition, the electrical resistance of the connections is minimized to optimize the configuration between the photodiode die light-receiving surface 252 and the reflective connection structures (e.g., p-side reflective electrical connections and n-side reflective electrical connections). is important. Referring again to FIG. 2, light of a desired wavelength, e.g., 405 nanometers or 450 nanometers, enters the photodiode structure 1000 through an aperture or window (not shown) and strikes the light receiving surface 252, Light can propagate through the substrate 101 and semiconductor layers and be reflected from the p-side and n-side reflective electrical connections 113 and 114 as well as edge reflectors (not shown). As shown in FIG. 2, light receiving surface 252 generally directs radiation emitted from optical illumination source 251 to an area of the photodiode die located between p-side reflective electrical connection 113 and n-side reflective electrical connection 114 . a portion of a photodiode device (or photodiode die) arranged and aligned to provide a In some embodiments, as shown schematically in FIG. 2, the light receiving surface 252 can include the area on the edge of the photodiode die. In other embodiments, light-receiving surface 252 may include an open area on one of surfaces 255 or 256 that provides for each of p-side reflective electrical connection 113 or n-side reflective electrical connection 114 . Does not include part of the material used to form it. In this configuration, the open area allows radiation emitted by the optical illumination source 251 to enter an area of the photodiode die located between the p-side reflective electrical connection 113 and the n-side reflective electrical connection 114. is designed to In some embodiments, light-receiving surface 252 is aligned with the photodiode die to receive light emitted from light illumination source 251 at least once, at least twice, at least three times, or at least five times. Again, the light can be reflected between the p-side reflective electrical connection 113 and the n-side reflective electrical connection 114 . The light emitted from the light illumination source 251 can have at least one wavelength between 390 nanometers and 460 nanometers, for example.

In one embodiment, the n-side reflective electrical connection includes a two-part mirror/n-electrode, which includes a discontinuous n-electrode 217 and an n-side reflective electrical connection 114, as shown in FIG. The discontinuous n-electrode 217 is optimized as an electrical connection and is manufactured, for example, as a titanium/aluminum or titanium/aluminum/gold laminate, where the titanium is about 5 to 200 nm thick and the aluminum or gold is about 100 nm to 1 micrometer thick. In one suitable embodiment, discontinuous n-electrode 217 is a grid electrode having grid openings of between about 1 micrometer and 1 centimeter on one side. In some embodiments, a portion of the surface beneath the grid electrode is roughened using, for example, a wet etching process prior to deposition of the grid electrode. In some embodiments, the rough surface has a root mean square roughness of between about 300 nanometers and about 1 millimeter, or between about 1 micrometer and about 200 micrometers. Assuming a working current density of 10 A/cm ² and a sheet resistance of 0.27 Ω/sq for an n-type GaN substrate, the percent power loss due to lateral conduction in the substrate layer is 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2. It is calculated to be approximately 0.4, 2.5, 9.8% for grating finger spacings of 5 and 1 cm, respectively. In some embodiments, an n-side reflective electrical connection is applied on the surface of the singulated die prepared from this structure in addition to or instead of the n-side reflective electrical connection on the back surface. In some embodiments, the n-connection and p-connection are each added to the same side of the die after trenching the n-type doped layer or the p-type doped layer as required. The grooves may be formed by lithography and dry or wet etching, as known in the art and described in more detail herein below. The n-side reflective electrical connection 114 comprises at least one of silver, gold, aluminum, platinum, rhodium, palladium, chromium, etc., on the rear surface of the substrate 101 and on the grid-like discontinuous n-electrode 217 . can be deposited on Preferably, the electrical connections are deposited after any annealing treatment to the discontinuous n-electrode to reduce interdiffusion. Optionally nickel, rhodium, platinum, palladium, iridium, ruthenium, rhenium, tungsten, molybdenum, niobium, tantalum, or MC _x N _y O _z where M is aluminum, boron, silicon, titanium, vanadium, chromium , yttrium, zirconium, lanthanum, or a metal element such as a rare earth metal, where x, y, and z are each between 0 and 3) are formed between the discontinuous n-electrode 217 and the n-side It is positioned between the reflective electrical connections 114 . The discontinuous n-electrodes 217 may instead be arranged in an array of dots, rectangles, circles, etc. in a plane parallel to the large area surface 102 rather than in a grid configuration. Preferably, the discontinuous n-electrodes 217 are spaced apart from each other by between about 1 micrometer and 0.1 cm. The use of a reflective metal n-electrode, or a combination of reflective electrical connections and discontinuous electrodes, allows the fabrication of large area power photodiodes without the need for lateral carrier migration over long distances through the substrate 101. This is true when the carrier density of the substrate 101 is low to optimize transparency, or when the substrate is fairly thin, such as less than about 100 microns, less than about 50 microns, or about 25 microns. may be significant if less than Parasitic light absorption by the discontinuous n-electrode can be minimized by designing the electrode pattern and light propagation path to avoid light being primarily incident on the discontinuous n-electrode pattern.

Photodiode structure 1000 has an average reflectance of at least 80% for wavelengths between 390 nanometers and 460 nanometers at a particular angle or range of angles at which light is incident during operation, and also has an average reflectance of 5× It may include an n-side reflective electrical connection with a connection resistance of less than 10 ⁻⁴ Ωcm ² .

In some embodiments, at least one of the p-side reflective electrical connection and the n-side reflective electrical connection further includes a semi-transparent current spreading layer 321, as shown in FIG. The semi-transparent current spreading layer 321 is made of nickel oxide (NiO), nickel oxide/gold (NiO/Au), NiO/Ag, indium tin oxide (ITO), p-type zinc oxide (ZnO), ruthenium oxide ( _RuO2 ), It may consist of or include at least one other transparent conductive oxide and the like. Semitransparent current spreading layer 321 facilitates electrical connection to p-type layer 111 or substrate 101, eg, ohmic or pseudo-ohmic behavior. In order to minimize light absorption in semi-transparent current spreading layer 321, this layer preferably has a thickness between about 1 nm and about 100 nm and a light transmission greater than 70%. Assuming a working current density of 10 A/cm ² and a sheet resistance of 25 Ω/sq for the semi-transparent current spreading layer 321 laminated on top of the p-type layer, the percent due to lateral conduction in the current spreading layer is The power loss is calculated to be about 0.4, 2.3, 9.1% for grid spacings of 0.02, 0.05, 0.1 cm, respectively.

In some embodiments, a transparent dielectric 319 is disposed over a portion of the semi-transparent current spreading layer 321 and between the discontinuous p-electrodes 315 and/or the discontinuous n-electrodes 317 . The transparent dielectric includes _{at least} one _{of TiO2} , _Ta2O5 , ZrO2, _SiO2 , _SiOx , _{SiNx , Si3N4} , _SiOxNy , _{Al2O3 ,} or _MgF2. sell. The transparent dielectric 319 may have a quarter-wave thickness, ie, a thickness approximately equal to one quarter of the incident photon wavelength in air divided by the refractive index of the dielectric medium. For example, if the photodiode structure 1000 has a design wavelength of 405 nanometers and the transparent dielectric is made of _Ta2O5 and has a refractive index of about _2.28 , then the thickness of the transparent dielectric 319 is about It can be chosen as 405/2.28/4=44 nanometers. Transparent dielectric 319 includes open areas in which discontinuous p-electrodes 315 or discontinuous n-electrodes 317 are disposed. Discontinuous p-electrode 315 and discontinuous n-electrode 317 may include at least one of nickel (Ni), nickel oxide (NiO), titanium-tungsten/gold (Ti--W/Au). In a preferred embodiment, discontinuous p-electrode 315 and/or discontinuous n-electrode 317 do not extend over the transparent dielectric. A p-side reflective electrical connection 113 is disposed over the transparent dielectric and electrical connection material to electrically interconnect the discontinuous p-electrodes 315 at various grid openings. An n-side reflective electrical connection 114 is disposed over the transparent dielectric and electrical connection material to electrically interconnect the discontinuous n-electrodes 317 at various grid openings. The p-side reflective electrical connection 113 and the n-side reflective electrical connection 114 also cooperate with the transparent dielectric 319 to define reflectors that reflect light within the device. Further variations of reflective metal connections are described in US Pat. No. 7,119,372, the contents of which are hereby incorporated by reference in their entirety.

In another set of embodiments, the semiconductor layers are transferred to one or more carrier substrates 1313 and the template substrate 1101 is removed, as shown schematically in Figures 13A, 13B, 13C. Compared to the structure outlined in FIG. 3, the p-side electrical connection similarly includes a semi-transparent current spreading layer 321 and a discontinuous p-electrode 315, and furthermore, a portion of the semi-transparent current spreading layer 321. It may include a transparent dielectric 319 disposed thereon (FIG. 13A). The carrier substrate 1313 is then covered by the p-type layer 111, the semi-transparent current spreading layer 321 if present, the discontinuous p-electrode 315 if present, or the transparent dielectric 319. If present, it is joined with one or more of them. The bonding of the carrier substrate or the light transmissive member 1313 may be by an adhesive or by one or more adhesive layers ( (not shown), or alternatively by conventionally known bonding methods. In some embodiments, the carrier substrate 1313 and the adhesive layer are transparent at wavelengths of interest for the packaged photodiodes, eg, wavelengths between 390 and 460 nanometers. In some embodiments, carrier substrate 1313 comprises one or more of glass, transparent ceramic, silica glass, borosilicate glass, aluminosilicate glass, quartz, sapphire, _MgAl2O4 spinel, zinc oxide, or aluminum _oxynitride . or consists of The adhesion _{layer is SiOx} , _{GeOx ,} SiNx, _AlNx , _{GaOx, Al2O3 , Sc2O3 , Y2O3 , B2O3 , R2O3} , where R is a rare earth element, MgO, CaO, SrO, _HfO2 , _ZrO2 , _Ta2O5 , or B, _Al , Si, P, Zn, Ga, Si, Ge, Au, Ag, Ni, Ti, Cr, Zn, Cd , In, Sn, Sb, Tl, or Pb, or oxides, nitrides, or oxynitrides thereof. The adhesion layer may be deposited by thermal evaporation, electron beam evaporation, sputtering, chemical vapor deposition, plasma enhanced chemical vapor deposition, or the like, or by thermal oxidation of a deposited metal film. The thickness of the adhesion layer can be between about 1 nanometer and about 10 micrometers, or between about 10 nanometers and about 1 micrometer. The adhesive layer can be annealed by heating to a temperature of between about 300° C. and about 1000° C., for example. In some embodiments, at least one adhesion layer is chemical-mechanically polished. In preferred embodiments, the root mean square surface roughness of at least one adhesive layer is less than about 0.5 nanometers, or less than about 0.3 nanometers in an area of 20×20 μm ² . In some embodiments, the thermocompression bonding is performed in a clean room with less than 10,000, less than 1,000, less than 100, or less than 10 particles per cubic centimeter of air. Just prior to wafer bonding, particles are removed from one of the surfaces by spraying, brushing, or using ionized nitrogen, _CO2 jets, _CO2 snow, high resistance water, or an organic solvent such as methanol, ethanol, isopropanol, or acetone. It can be removed by a rinse treatment using a solvent or the like. In some embodiments, the opposing surfaces are brought into contact while immersed in the liquid. Optionally, at least one of the faces is exposed to plasma to enhance wafer bonding. The pressure between the opposing surfaces during the thermal compression bonding process is between about 0.1 MPa and about 100 MPa, and the temperature is between about 30° C. and about 950° C., between about 30° C. and about 400° C. C. or between about 30.degree. C. and about 200.degree. C. for a period of between about 1 minute and about 10 hours.

A p-side reflective layer 1315 may be deposited on the side of the carrier substrate 1313 opposite the photodiode structure 1000 . The P-side reflective layer 1315 may comprise or consist of one or more of silver, a dielectric mirror, and a distributed Bragg reflector (DBR). The p-side reflective layer 1315 has about 80% reflection at the design wavelength of the packaged photodiode, e.g., between 360 and 460 nanometers, at a particular angle or range of angles at which light is incident during operation. It can have a reflectivity that is higher, greater than about 85%, greater than about 90%, greater than about 95%, greater than about 97%, or greater than about 98%.

As shown schematically in FIG. 13B, the photodiode structure 1000 can be separated from the template substrate 1101 by a laser lift-off method. Laser beam 1321 may raster the back surface of substrate 101 . In one embodiment, a single crystal group III metal nitride layer 1104 is deposited on a template substrate 1101, such as a sapphire substrate, and an ultraviolet laser beam is focused at the interface between the single crystal group III metal nitride layer 1104 and the template substrate 1101. , resulting in local decomposition of the rear surface of single-crystal group-III metal nitride layer 1104 and formation of micro- or nanobubbles of N ₂ , thus separating template substrate 1101 from the rest of photodiode structure 1000 . In some embodiments, the single crystal group III metal nitride layer ^{1104 absorbs more than 1000 cm −1 at at least one wavelength with the remainder of the template substrate 1101 being substantially transparent and having a light absorption coefficient less than 50 cm −1 .} A laser beam 1321 having a wavelength at which the release layer 1103 absorbs strongly is focused onto the release layer 1103, resulting in localized decomposition and formation of micro- or nanobubbles of _N2 . , thereby separating the template substrate 1101 from the rest of the photodiode structure 1000 . By adjusting the temperature, laser power, laser spot size, laser pulse width, and/or laser pulse number of the photodiode structure 1000, the interface can be adjusted without undesirable damage to high quality epitaxial layers or semiconductor structures. It can be weakened to the optimum degree. Laser fluences that effect separation can be between 300 and 900 mJ/cm ² , or between about 400 mJ/cm ² and about 750 mJ/cm ² . Uniformity of the laser beam 1321 is improved by including a beam homogenizer in the beam path, and the beam size can be approximately 4 mm x 4 mm. In some embodiments, the laser beam 1321 scans or rasters the release layer rather than being held stationary. Separation can be carried out at temperatures above the melting point of the metal resulting from decomposition, eg, above about 30° C. for gallium metal.

Alternatively, the photodiode structure 1000 can be separated from the template substrate 1101 by photoelectrochemical etching, as shown schematically in FIG. 13C. In one embodiment, exfoliation layer 1103 comprises InGaN and has a bandgap less than that of the absorber layer. A trench 1322 may be formed between adjacent carrier substrates 1313 through each semiconductor layer to the exfoliation layer 1103 to form a mesa. The grooves 1322 may be formed by dry etching or wet etching after lithography, as is conventionally known. Photodiode structure 1000 can then be immersed in a photoelectrochemical etchant and illuminated with light having a wavelength that is highly absorbed by exfoliation layer 1103 but not by at least some of the other semiconductor layers. In some embodiments, _the etchant includes potassium _hydroxide (KOH), potassium persulfate ( _K2S2O8 ), sodium hydroxide ( _NaOH ), hydrogen peroxide ( _H2O2 ), ethylene glycol, and including one or more of tetramethylammonium hydroxide (TMAH). KOH can have a concentration between 0.01 and 10 molar, or between about 0.1 and about 2 molar. In some embodiments, the light source includes a broadband light source such as a mercury arc lamp, mercury xenon lamp, tungsten lamp, or LED. In some embodiments, the light source is coupled with a filter to remove wavelengths that are highly absorbed by one or more of the semiconductor layers. The fluence of the light source can be between about 1 W/cm ² and about 50 W/cm ² . In one embodiment, the photodiode structure 1000 is electrically connected to the anode and the separate cathode is immersed in the etchant. In some embodiments, a current is passed between the cathode and the anode to melt the release layer 1103 starting at the base of the groove 1322 and extending laterally. In other embodiments, the photoelectrochemical etching process is electrodeless. In some embodiments, oxidation and _melting of the release layer is facilitated by an oxidizing agent such as _K2S2O8 present in the etchant _. After etching for a predetermined time, the exfoliation layer 1103 is substantially melted, allowing the photodiode structure 1000 to be easily removed from the template substrate 1101 .

After removal of the template substrate 1101, as shown schematically in FIG. 13D and described above, at a particular angle or range of angles at which light is incident during operation, greater than about 70%, greater than about 80%, or An n-side reflective electrical connection 1319 having a reflectivity of greater than about 90%, greater than about 95%, greater than about 97%, or greater than about 98% is formed on the single crystal Group III metal nitride layer 1104. can be deposited on the newly exposed rear surface 1317 of the . In some embodiments, surface 1317 is cleaned by one or more of wet or dry processes prior to deposition of n-side reflective electrical connection 1319 . In operation, light from the light illumination source 251 is incident on the carrier substrate 1313 as a beam 1353 through an aperture or light receiving surface 1352 and is transmitted between the p-side reflective layer 1315 and the n-side reflective electrical connection 1319. reflected many times.

Variations of the template substrate detachment process and the carrier substrate bonding process are also possible. For example, a first carrier substrate 1411, which may be transparent or opaque, is bonded to the p-side reflective electrical connection 113, as shown schematically in FIG. 14A. First carrier substrate 1411 can comprise or consist of one or more of sapphire, silicon carbide, zinc oxide, silicon, _SiO2 , glass, copper, silver, and aluminum. The template substrate 1101 is then removed by a process similar to the process already described and outlined in FIGS. 13B, 13C, followed by the translucent current spreading layer 321 as shown schematically in FIG. 14B and already described. can be deposited on the newly exposed rear surface 1417 of the single crystal group III metal nitride layer 1104 . Semi-transparent current spreading layer 321 facilitates electrical connection, eg, ohmic or pseudo-ohmic behavior, to single crystal group III metal nitride layer 1104 . In some embodiments, a transparent dielectric 319 is disposed over a portion of the semi-transparent current spreading layer 321 and between the discontinuous n-electrodes 317 . In one embodiment, discontinuous n-electrode 317 is highly reflective and transparent dielectric 319 is an anti-reflective layer. As shown in FIG. 14C, the first surface of the second carrier substrate 1413, which is transparent at the wavelength of interest, is then coated with a monocrystalline group III metal nitride layer 1104, a semi-transparent current spreading layer 321, and a discontinuous n-electrode 317. , and/or bonded to the transparent dielectric 319 . An n-side reflective layer 1414 can then be deposited on the second surface of the second carrier substrate 1413, which acts as a light transmissive member. Here, light from the light irradiation source 251 passes through an aperture or light receiving surface 1452 and enters the carrier substrate 1313 as a beam 1453, and passes through the p-side reflective electrical connection 113 and the n-side reflective layer 1414 several times. is also reflected.

In some embodiments, both the n-type and p-type electrical connections are placed on the same side of the light transmissive member, as shown schematically in Figures 16A, 16B, 16C. In some embodiments, the light transmissive member comprises or consists of a substrate having a semiconductor layer deposited thereon. In other embodiments, the semiconductor layer is removed from the substrate and then bonded to the light transmissive member. The substrate or light-transmissive member, together with the semiconductor layers and dielectric layers, if present, is a device cavity region 1669 through which light is reflected many times as it is absorbed in the absorbing layer 107. can be defined. In some embodiments, the device cavity region 1669 can additionally include a portion of the optical cavity region including regions filled with air, gaseous or liquid fluids, or dielectrics. . Several embodiments of light transmissive members and lateral electrical connections are described in greater detail below.

In one particular embodiment, as shown in FIG. 16A, the electrical connections are located on the device layer on the template substrate 1101 and are located adjacent to the mesas 1651 on the template substrate 1101 to define the device cavity regions 1669 . definable. In device cavity region 1669 , the light transmissive member is substrate 101 and the reflective members are p-side reflective electrical connection 113 and n-side reflective layer 1414 . Such a configuration may have advantages, for example, if the template substrate 1101 is electrically insulating. After depositing p-type layer 111 and optional semi-transparent current spreading layer 321, trenches 1653 may be formed between adjacent mesas 1651 by lithography and dry etching using conventionally known processes. The depth of trench 1653 is minimal, with regions of n-type first non-absorbing layer 105 exposed but most of the thickness of n-type first non-absorbing layer 105 remaining intact under trench 1653 . can be selected to allow excellent lateral electrical conduction with an ohmic loss of . The p-side reflective electrical connection 113 can be deposited before or after the groove 1653 is formed. An n-side electrical connection 1657 can be deposited on the exposed portion of the n-type first non-absorbing layer 105 . An insulating dielectric layer 1655 is disposed between the p-side reflective electrical connection 113 and the n-side electrical connection 1657 . The insulating dielectric layer 1655 is deposited by, for example, plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), or high density plasma chemical vapor deposition (HDPCVD) and is made of _SiO2 , _SiNx , Al. ₂ O ₃ and the like. In some embodiments, an insulating dielectric layer 1655 is deposited after one or both of the p-side reflective electrical connection 113 and the n-side electrical connection 1657 . In some embodiments, an insulating dielectric layer 1655 is deposited before one or both of the p-side reflective electrical connection 113 and the n-side electrical connection 1657 . The connection resistance of the n-side electrical connection portion 1657 is less than 1×10 ⁻³ Ωcm ² , less than 5×10 ⁻⁴ Ωcm ² , less than 2×10 ⁻⁴ Ωcm ² , less than 10 ⁻⁴ Ωcm ² , and 5×10 ^{−5 .} less than Ωcm ² , less than 2×10 ⁻⁵ Ωcm ² , or less than 10 ⁻⁵ Ωcm ² . In preferred embodiments, the connection resistance is less than 5×10 ⁻⁵ cm ² . The n-side electrical connection 1657 can include at least one of silver, gold, aluminum, nickel, platinum, rhodium, palladium, titanium, chromium, and the like. In one embodiment, the surface on which the n-side electrical contact is located is exposed to SiCl ₄ plasma to reduce the electrical contact resistance prior to deposition of the n-side electrical contact. An n-side reflective layer 1414 can then be deposited on the rear surface 1659 of the template substrate 1101 . The n-side reflective layer 1414 can comprise or consist of one or more of silver and aluminum. to enable reflectivity greater than 80%, greater than 85%, greater than 90%, greater than 95%, greater than 97%, or greater than 98%, optionally Prior to deposition of the n-side reflective layer 1414, the rear surface 1659 can be ground and/or polished and optionally chemical-mechanically polished. In a preferred embodiment, after die singulation, the width of mesa 1651 is much larger than the width of groove 1653 , resulting in an extremely large amount of light internally reflected between p-side reflective electrical connection 113 and n-side reflective layer 1414 . A very small portion is lost out the side of the device. In some embodiments, the n-side electrical connection 1657 can be highly reflective, having a reflectivity greater than 70%, greater than 80%, greater than 90%, or greater than 95%.

In some embodiments, the device is flip-chipped such that both p-type and n-type electrical connections are placed on the same side of the device structure. Such a configuration can have advantages, for example, if the template substrate 1101 is optically transparent but electrically insulating. Referring to FIG. 17A, after deposition of the p-type layer 111, two or more vias are formed through the p-type layer 111, the second non-absorbing layer 109, if present, and the absorbing layer 107. through to the n-type first non-absorbing layer 105 . Vias may be formed by conventional lithography and dry etching processes such as reactive ion etching (RIE), inductively coupled plasma (ICP), or chemically reactive ion beam etching (CAIBE). depositing an insulating dielectric layer 1616 on the sidewalls of the via, for example by plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), or high density plasma chemical vapor deposition (HDPCVD); The insulating dielectric layer 1616 can include _SiO2 , _SiNx , _Al2O3 , and the _like . A p-side reflective electrical connection 113 may be deposited on a portion of the p-type layer 111 between the vias, and an n-side reflective electrical connection 1614 may be located in the via. A dielectric reflective layer 1618 or a metallic n-side reflective layer may be deposited on the rear surface of substrate 101 or template substrate 1101 . Light of a desired wavelength, eg, 405 nanometers or 450 nanometers, enters photodiode structure 1000 through an opening or window (not shown) that may include receiving surface 252 , and emitted light passes through substrate 101 . and propagate in the semiconductor layers and can be reflected from the p-side reflective electrical connection 113, the n-side reflective electrical connection 1614, from the dielectric reflective layer 1618, and from the edge reflectors (not shown). Light within the device is somewhat scattered from the materials placed in the vias. However, since the area fraction of the vias is relatively small and the depth is small compared to the thickness of the substrate 101, there will be some scattering.

In an alternative embodiment, the vias are located on the n-side rather than the p-side, as shown schematically in FIG. 17B. For example, referring again to FIG. 13C, after removing template substrate 1101, rather than depositing or bonding n-side reflective electrical connection 1319 to surface 1317 as shown schematically in FIG. , two or more vias, the monocrystalline group III metal nitride layer 1104, the n-type first non-absorbing layer 105, and the absorbing layer 107, and if there is a second non-absorbing layer 109, It can be etched through to p-type layer 111 or semi-transparent current spreading layer 321 . An insulating dielectric layer 1616, a p-side reflective electrical connection 1615, and an n-side reflective electrical connection 1663 similar to the structure of the photodiode die 1002 as shown in FIG. 17A may be disposed.

Referring again to FIG. 16B, in one embodiment, electrical connections are placed on the device layers below and laterally of the carrier substrate 1313 . Such a configuration may be advantageous when the carrier substrate 1313 is optically transparent but electrically insulating and constitutes another example of a light transmissive member. For example, p-side reflective electrical connection 1661 may be placed in contact with one or more of p-type layer 111 , semi-transparent current spreading layer 321 , discontinuous p-electrode 315 , and transparent dielectric 319 . Using a dicing saw, the carrier substrate 1313 is cut into gaps or grooves 1654 adjacent to or surrounding the carrier substrate 1313 and in which the p-side reflective electrical connection 1661 is disposed; 1313 may be formed by one or more of, for example, wet or dry etching through portions remaining after cutting with a saw, or bonding multiple individual carrier substrates 1313 rather than a single large carrier substrate. . An n-side reflective electrical connection 1319 may be deposited on the underside of the single crystal group III metal nitride layer 1104 .

Referring again to FIG. 16C, in one embodiment, electrical connections are placed on the lower and lateral device layers of the second carrier substrate 1413, which constitute yet another embodiment of the light transmissive member. sell. Such a configuration may be advantageous if the second carrier substrate 1413 is optically transparent but electrically insulating. For example, n-side reflective electrical connection 1663 is placed in contact with one or more of single crystal group III metal nitride layer 1104 , semi-transparent current spreading layer 321 , discontinuous n-electrode 317 , and transparent dielectric 319 . sell. A gap or groove 1656 adjacent to or surrounding the second carrier substrate 1413 and in which the n-side reflective electrical connection 1663 is disposed is formed through the second carrier substrate 1413 with a dicing saw. cutting using a wet or dry etch through the portions left after cutting, for example with a saw, or a number of individual second carrier substrates 1413 rather than a single large carrier substrate. It may be formed by one or more of joint placement.

In some embodiments, the photodiode structure 1000 can be characterized prior to singulation. For example, optical properties such as transmittance or reflectance can be examined by optical absorption spectroscopy. The topography of one or more layers may be characterized by differential interference contrast microscopy (DICM or Nomarski) and/or atomic force microscopy. Luminescent properties of one or more epitaxial layers can be characterized by one or more of photoluminescence spectroscopy, photoluminescence microscopy, and microfluorescence. Impurity concentrations in one or more layers may be characterized by calibrated secondary ion mass spectroscopy (SIMS). Crystallinity of one or more epitaxially grown layers may be characterized by X-ray diffraction. Electrical properties of one or more layers may be characterized by Hall measurements, Van der Pauw measurements, or unconnected resistance measurements. One or more of the p-side and n-side reflected electrical connections, as well as the connection resistance and series resistance of one or more layers may be examined by transmission line measurements (TLM). The electrical properties and power conversion efficiency of the photodiode are characterized by current-voltage (IV) measurements either in the dark or under illumination with a conventional light source or a laser light source of varying intensity. can be Minority carrier collection within the photodiode structure 1000 can be quantified by quantum efficiency measurements. Photodiode structure 1000 may be further characterized by electroluminescence measurements.

After wafer-level fabrication, the individual photodiode dies can be separated and packaged by, for example, laser scribing and cleaving, laser cutting, stealth dicing, die sawing, and the like. The dicing or cleaving direction relative to the crystallographic axis can be selected to control the shape of the edges. For example, c-plane fabricated photodiode wafers, including semiconductor layers, reflective p-type and/or n-type connections, and other device features, may be cleaved along the m-plane for smooth cleaved surfaces, or , m-plane facets can be cleaved along the a-plane to provide a rough cleave plane composed of m-plane facets.

Figures 18A-18E are side, cross-sectional, and plan views showing simplified schematics of a photodiode die 1002 of a photodiode designed and packaged for lateral illumination through a corner or edge. FIG. 18E includes dashed lines indicating the viewing position of the drawings shown in FIGS. 18A-18D. In addition to the n-side reflective electrical connection 114 and the p-side reflective electrical connection 113, by deposition or formation of a passivation layer, or by one or more processing techniques (e.g., plasma-generated ions or radicals). The side edges of one or more of the absorbing layers may be passivated (e.g., by subjecting the existing layers to an exposing treatment, reactive annealing treatment, etc.) to reduce shunt current paths along the device edge (e.g., this Also referred to herein as edge passivation). In some embodiments, the passivation treatment comprises or _consists of a coating, wherein the coating is _AlNx , _{Al2O3 , TiO2 , Ta2O5} , ZrO2, _SiO2 , _SiOx , _SiNx , Si _{3N4 , SiOxNy , AlOxNy , or SiuAlvOxNy . _} In some embodiments, the passivation film or layer is deposited by atomic layer deposition (ALD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), high density plasma chemical vapor deposition (HDPCVD), or It is deposited by electron cyclotron resonance (ECR) plasma deposition. In some embodiments, the deposited passivation layer contains hydrogen at a concentration greater than 10 ¹⁹ cm ⁻³ , which deactivates dangling point defects at the interface between the semiconductor layer and the passivation layer. . In some embodiments, the passivation layer has a lower work function than the semiconductor layer. In some embodiments, edge passivation is not used on or formed on the photodiode die.

At one location on the edge of the photodiode die, the edge includes an optical window 912 . The optical window 912 can be coated with an antireflective optical window layer 911 and the remaining portion around the edge can be coated with an edge reflective layer 905 . In some embodiments, the edge optical window 912 portion, instead of or in addition to the anti-reflection optical window layer 911, includes a surface with a desired roughness or texture. In some embodiments, optical windows 912 are located at the corners. In other embodiments, the optical windows 912 are positioned away from the corners. The area of the optical window 912 is less than about 40%, less than about 30%, less than about 20%, less than about 10%, less than about 5% of the surface area of the at least one absorbing region, measured in a plane parallel to the large area surface 102. %, less than about 2%, less than about 1%, less than about 0.5%, less than about 0.2%, or less than about 0.1%. The anti-reflection optical window layer 911 comprises at least one of MgF2 _{, SiO2} , _Al2O3 , _HfO2 , _{LaTiO3 , Si3N4} , or _TiO2 , and is e-beam deposited, _sputtered , or It can be deposited by other suitable deposition techniques. In some embodiments, the antireflective optical window layer 911 has a texture. In some embodiments, the angle between the surface normal of the edge of the optical window 912 and the surface normal of the substrate can deviate from 90 degrees. Optical window 912 may include one or more planar layers and/or textured structures. In one embodiment, the direction of the optical window 912 is parallel to the edge of the die. In other embodiments, the optical window has an outward direction that is not parallel to the edge of the die, eg, to minimize optical loss when splicing into the fiber at non-normal incidence angles. The edge reflective layer comprises at least one of silver, gold, aluminum, platinum, rhodium, palladium, chromium, etc., and may be deposited by e-beam deposition or sputtering. In some embodiments, the edge reflective layer can include a dielectric layer to enhance edge reflection. Light entering the optical window 912 traverses a number of times through a combination of semiconductor layers (including a non-absorbing portion, an absorbing portion, and a p-type contact semiconductor layer) 915 (FIGS. 18C-18D) disposed on the substrate.

The die can be attached to one or more of the lower heatsink 901 or the upper heatsink 909 . A separate submount may also be provided and positioned between the die and either the lower heat sink 901 or the upper heat sink 909 . Heat sinks and submounts may include layers and/or plates or other features including at least one of copper, aluminum, silicon, silicon carbide, sapphire, aluminum nitride, beryllium oxide, diamond, and the like. Photodiode die 1002 may be attached to a heat sink and/or submount by one of Au/Sn eutectic, Au/Ge eutectic, or similar bonding layers.

19A, 19B, 19C, 19D, and 19E are cross-sectional and plan views, respectively, that schematically illustrate the optical path from optical fiber 1001 to photodiode die 1002. FIG. The optical fiber 1001 described with respect to Figures 19A-19E is constructed similarly to the optical fiber 3180 described in greater detail below. In these figures, the X direction is chosen along the first direction in the plane of the photodiode die (i.e., parallel to the large area plane 102), and the Y direction is perpendicular to the X direction in the plane of the die. and the Z direction is chosen to be perpendicular to the plane of the die. The optical fiber 1001, which may have an antireflection coating 1003, is placed in the optical window 912 at an angle α to the plane of the photodiode die (see FIG. 19A) and at the die edge 1902 (see FIG. 19B). can be connected at an angle β to In one example, the plane of the photodiode die is generally parallel to the major surface of semiconductor layer 915, which is parallel to the XY plane of FIG. 19A. In some embodiments, as shown in FIG. 19B, the optical fiber 1001 is arranged such that the photodiode die also includes an angle Δ with respect to the edge 1901 (eg, the receiving edge of the photodiode die 1002 of FIG. 19B). Connected. When the angle α deviates from zero degrees, the light incident on the die is reflected many times from the p-type and n-type reflective connections. In some embodiments, total internal reflection may be utilized at the top and bottom mirrors. In some embodiments, the value of α is between 0 and about 50 degrees, between 0 and about 40 degrees, between 0 and about 20 degrees, or between 0 and about 5 degrees, or even 0. It is chosen to be between 1 and 5 degrees. When the angle β deviates from zero degrees, the light incident on the die is reflected many times from the edge reflective layer, illuminating the entire die volume. For relatively small values of β, light is reflected progressively from one edge of the photodiode die to the other (FIG. 19B). As the value of β increases, light traverses the die with fewer reflections (FIG. 19C). In certain embodiments, the value of β is between 0 and about 60 degrees, between 0 and about 20 degrees, between 0 and about 10 degrees, between 10 and about 30 degrees, or between about 30 and about 50 degrees. is selected to be between In some embodiments, the die is narrow in the Y direction, e.g., the width is between 5 and 0.5 times the thickness of the die, between 2 and 0.8 times the thickness of the die, or Between 1.5 and 1 times the thickness of the die, the value of β can be as small as, for example, less than about 20 degrees, less than about 10 degrees, less than about 5 degrees, or nearly zero. At , the light travels to the far end of the die and is then reflected back along substantially the same optical path. In one embodiment, the reflection from the edge of the die uses total internal reflection, i.e., the angle of incidence of the internal ray with respect to the surface normal is (360/(2π))*arcsin(n ₁ /n ₂ ) , where _n1 is the outer refractive index and _n2 is the inner refractive index. In some embodiments, the value of angle Δ is between 0 and about 20 degrees, between 0 and about 10 degrees, or between 0 and about 5 degrees, or even between 0.1 and 5 degrees. is selected as

One or more optical fibers may be connected to the photodiode die using a fixture that includes one or more of connectors and ferrules by conventionally known methods. In one embodiment, as shown in FIG. 36, the fixture 3601 secures the support structure 3611, the mounting plate 3610, and the light emitting end 3182 of the optical fiber 3180 to the edge 1901 of the photodiode die 1002 (e.g., FIG. 19B, 36) or a surface (eg, the surface containing the n-side reflective electrical connections of FIGS. 33A-33I). Optical fiber 3180 is positioned and attached to surface 3609 of mounting plate 3610 using mounting element 3620 . Mounting element 3620 may comprise a simple clamping device configured to hold a portion of the optical fiber. However, in some embodiments, mounting element 3620 can include one or more retaining features configured to support a connector or ferrule connected to a portion of optical fiber 3180 . A photodiode die 1002 is also positioned and attached to surface 3609 of mounting plate 3610 . In some embodiments, the photodiode die 1002 is attached to the surface 3609 of the mounting plate 3610 with removable clamps, fixing elements, adhesives, metal or ceramic bonding layers, or other similar devices or devices known in the art. Bonded or clamped using device holding methods. In some embodiments, photodiode die 1002 includes a heat sink 901 positioned between the active area of photodiode die 1002 and surface 3609 of mounting plate 3610 . In some embodiments, a submount (not shown) is placed between photodiode die 1002 and heat sink 901 . In some embodiments, the first end of the optical fiber 3180 (i.e., emitting end 3182), the major axis 3181A of the optical fiber (FIGS. 31B, 36), and the first edge and first edge of the photodiode die. between about 1 micrometer and about 1 millimeter, or between about 1 micrometer and about 100 micrometers, or between about 2 micrometers and about 50 micrometers, or Control with a tolerance of between about 3 microns and about 25 microns. In some embodiments, the fixture positions the optical fiber radiation output end 3182 from the surface of the optical window 912 to a first distance 3630 (FIG. 36) that is between about 2 microns and about 10 millimeters. configured to place In configurations where the radiation exit end 3182 of the optical fiber 3180 is not parallel to the edge 1901 of the photodiode die 1002 or the surface of the optical window 912, the first distance It can be measured from a point extending through 3182 to the surface of the optical window 912 or to the center of the emitted radiation striking the edge 1901 of the photodiode die 1002 . Similarly, in configurations where the radiation output end 3182 of the optical fiber 3180 is not parallel to the light receiving surface of the optical coupling member 3187 (FIGS. 33A-33E) or the light receiving surface of the optical waveguide 3190 (FIGS. 31A-32), the first A distance (eg, distance D ₁ in FIG. 31B) from the point where major axis 3181A extends through radiation output end 3182 of optical fiber 3180 is the distance of the output radiation striking the receiving surface of optical coupling member 3187 or optical waveguide 3190. It can be measured to the center.

The fixture generally holds the relative position of the light emitting end 3182 of the optical fiber 3180 relative to the light receiving edge 1901 of the photovoltaic die 1002 constant within a tolerance of between about 1 micrometer and about 1 millimeter. provide a structure for use in In some embodiments, mounting plate 3610 is formed from a material having a coefficient of thermal expansion (CTE) to match that of optical fiber 3180 and/or photodiode die 1002 to facilitate operation of the photodiode package. while helping to maintain desired tolerances. In one example, mounting plate 3610 comprises a material such as Kovar®, Invar, or other material having a similar CTE to the material forming optical fiber 3180 and/or photodiode die 1002. .

In some embodiments, the ends of one or more optical fibers, which may be single mode or multimode, comprising or consisting of one or more of silica, glass, and plastic, are bonded to the ferrule with an adhesive such as epoxy. can be attached with Ferrules that may be used in the fixture may consist of or include ceramic, stainless steel, aluminum, copper, or plastic. The end face of the ferrule, as well as the end of one or more optical fibers (ie, radiation output end 3182), can also be polished. A ferrule can be attached to the fixed part by a connector. the position of the photodiode die 1002 within the fixed portion precisely controls the lateral dimension of the die, e.g., 100 microns, 50 microns, 25 microns, or better than 10 microns; and By placing a first edge (e.g., edge 1901) and a second edge of the die, a submount to which the die is attached, or a heat sink 901 to which the submount is attached, against a feature of the fixture, can be determined. Photodiode die 1002 is attached to mounting plate 3610 of fixture 3601 by gold-tin soldering, Au-Au thermal compression bonding, epoxy, silver epoxy, sintered silver interface material, or thermal adhesive, as described above. It can be attached by one or more. One or more of submounts and heat sinks may be included in the thermal and mechanical path between the photodiode die and the fixture. Photodiode die and submount, submount and heatsink, and heatsink and fixture, respectively, gold-tin soldered, Au-Au thermal compression bonding, epoxy, silver epoxy, sintered silver interface material, or thermal glue can be joined by one or more of The submount may consist of or include one or more of silicon, glass, sapphire, silicon carbide, beryllium oxide, diamond, copper-tungsten alloy, or aluminum nitride. Heat sink 901 may consist of or include one or more of copper and aluminum.

The edge light coupling arrangement shown in FIGS. 19A-19D facilitates high optical reflectivity from the front and back surfaces of the device due to its simplicity and large angle of incidence of light received from optical fiber 1001. It has a number of advantages, including However, these arrangements can also have some drawbacks, which are resolved in the alternative arrangements described below. For example, optical coupling is most efficient with an edge-coupled arrangement when the device is thicker than the diameter of the optical fiber, or at least thicker than the core diameter of the optical fiber, without incorporating focusing optics. sell. GaN, sapphire, and other substrate thicknesses are often on the order of 300 microns, which can be a challenge for some optical fibers. For example, in some embodiments, optical fiber 1001 can be a single mode fiber with a fiber core diameter of less than about 15 microns. However, the power transmitted from the one or more laser diodes is greater than 1 Watt, greater than 2 Watts, greater than 5 Watts, greater than 10 Watts, greater than 20 Watts, or greater than 50 Watts. In other embodiments that may be useful for such high power applications, the optical fiber 1001 has a fiber core diameter between about 25 micrometers and about 500 micrometers, between about 40 micrometers and about 300 micrometers. or between about 50 microns and about 200 microns. In still other embodiments, optical fiber 1001 actually has an overall diameter of between about 100 microns and about 5 millimeters, or between about 200 microns and about 2 millimeters, or between about 250 microns. A fiber optic bundle, or fiber optic bundle, between about 1 millimeter. A second challenge is that fairly precise alignment between the fiber and the device may be required to ensure that the desired proportion of optical radiation is delivered to the photodiode die 1002 . A third challenge is that the high intensity of light during its initial passage through the absorber layer or active region creates a high density of electron and hole carriers at certain locations within the photodiode, causing a high density in the absorber layer. concentration of carriers, and also can result in significant non-radiative Auger recombination leading to loss of efficiency. The active region generally includes an absorber layer that can include one or more layers having different compositions and/or material properties.

In some embodiments, as shown schematically in FIG. 19E, light is directed from a fiber oriented substantially perpendicular to the surface of the die (i.e., in the Z direction) to the surface of mirror 1005 and then onto one or two , are simultaneously transmitted to three, four, or more die edges. This arrangement can have the advantage of enhancing optical coupling and leveraging the developed supply chain of fiber splice fixtures.

Side-incident die arrangements such as those shown in FIGS. 19A, 19B, 19C, and 19D have the advantage of being relatively simple and easy to manufacture. Nevertheless, in these embodiments, if the substrate is maintained at a thickness greater than the optical fiber or fiber bundle, e.g., about 100 microns, 200 microns, 300 microns, or 500 microns, can be beneficial. Furthermore, the relatively long path caused by the launch orientation of the optical radiation into the side-incident die arrangement as shown in FIGS. should be minimized. In some embodiments, as shown in FIGS. 27A, 27B, the light is attached to the first light transmissive member (eg, substrate 101) or, in some embodiments, to the edge reflective layer 905. Coupled with the directly attached second light transmissive member 2101, it provides efficient lateral diffusion of light through the device. In these embodiments, the optical cavity region additionally includes a second light-transmissive member 2101 on the substrate 101, the latter being the main component of the device cavity region. In embodiments such as the one shown in FIG. 14B, substrate 101 may already be removed and second light transmissive member 2101 may be directly optically connected to semiconductor layer 915 . The second light transmitting member may consist of or include _SiO2 , _Al2O3 , or _the like. In some embodiments, total internal reflection may be utilized with the second light transmissive member. In some embodiments, a reflective structure composed of dielectric and metal layers can be placed on one or more of the surfaces of the second light transmissive member to enhance internal reflection. In some embodiments, the interface between the second light-transmissive member and the III-N substrate is rough or patterned, between 30 nanometers and 100 micrometers, or between 50 nanometers and 10 micrometers. It can have RMS height variations between meters. In some embodiments, one or more surfaces of the second light transmissive member are rough. In some embodiments, a dielectric antireflective coating layer is deposited on the Group III-N surface. In one embodiment, the second light transmissive member 2101 is selected to be thicker than the diameter of the optical fiber connected to it in the assembly.

20A-20E are schematic side, cross-sectional, and plan views of a photodiode die 1002 of a photodiode designed and packaged for top or bottom illumination near a corner or edge. is. FIG. 20E includes a dashed line indicating the viewing position of the drawings shown in FIGS. 20A-20D. Edge passivation, antireflection window film 1111, edge reflective layer 905, etc. are similar to those described for FIGS. However, in some embodiments, the back surface of the substrate, together with the n-type reflective electrical connections, is shaped such that light incident through an optical window 1119 having an anti-reflection coating 1111 on the die is reflected at different angles, Light is diffused laterally through the die via reflection by subsequent p-type and n-type reflective layers. In some embodiments, the orientation of optical window 1119 is parallel to the top or bottom surface of the die. In other embodiments, the optical window 1119 has an outward direction that is not parallel to either the top or bottom surface of the die, for example, to minimize optical loss when coupled into a fiber at non-normal incidence angles.

In some embodiments, the reflective member 2020 (FIG. 20C) in contact with the substrate or light transmissive member steers the direction of light propagation within the device cavity region by greater than about 30 degrees, greater than about 45 degrees, or Vary more than about 60 degrees. In some embodiments, reflective member 2020 changes the propagation direction of the first reflection of light incident on the device cavity region by an angle between about 40 degrees and about 140 degrees. These embodiments enable efficient splicing to fibers with diameters greater than the thickness of the substrate, increasing robustness and optical coupling stability, or expanding the growing product supply chain of fiber splice fixtures. It may have advantages in obtaining a leverage effect.

Figures 21A and 21B are cross-sectional and plan views, respectively, that schematically illustrate the optical path from an optical fiber to a top/edge illuminated photodiode die similar to the configuration shown in Figures 20A-20E. The fiber is spliced to an optical window with an antireflection coating 1111 at an angle γ (see FIG. 21A) to the surface normal of the photodiode die. In some embodiments, the value of γ is between 0 and about 60 degrees, between 0 and about 40 degrees, between 0 and about 20 degrees, or between 0 and about 5 degrees, or even 0.1 and 5 degrees. When the angle γ deviates from zero degrees, the light incident on the photodiode die is reflected many times from the p-type and n-type reflective connections. However, in this case, the reflector (eg, the n-side reflective electrical connection of FIG. 21A One or more non-flat features of the portion 114 layer) cause light to be reflected away from the entrance aperture 1119 (FIG. 21B) in various lateral directions. In some embodiments, total internal reflection may be used at the edge mirrors.

Figures 22A-22E are side, cross-sectional, and plan views showing simplified schematics of a photodiode die of a photodiode designed and packaged for top or bottom illumination at the center or middle of the die. . Edge passivation, anti-reflection coatings, edge reflective layers, etc. are similar to those described for FIGS. However, in some embodiments, the back side of the substrate (e.g., the heat sink 901 side), along with the n-side reflective electrical connection 114, is passed through an optical window (i.e., entrance aperture 1119) having an anti-reflection coating 1111 on the die. Shaped such that incident light is reflected at different angles, the light is spread laterally through the die via reflection from subsequent p-type and n-type reflective layers. In some embodiments, the n-type reflective electrical connection 114 has conical or pyramidal features formed therein such that light incident from the entrance aperture is directed laterally into the entrance aperture 1119 in multiple directions. reflected away from

The top (or bottom) incidence die arrangement shown in FIGS. 22A-22E may require more complex manufacturing steps than the edge incidence designs described above (eg, FIGS. 2, 13D, 14B, 17, 19A, etc.). For example, before or after deposition of the semiconductor and p-type reflective connect layers, and before deposition of the n-type reflective layer, non-planar features must be placed or formed on the substrate. Non-flat features (eg, hemispherical, pyramidal, or conical) can be formed by at least one of lithography, laser ablation, grinding, wet etching, and dry etching. Residual surface damage from laser, grinding, or dry etching processes can be removed with a wet etch. In some embodiments, the substrate has a thickness of, for example, less than 300 microns, less than 200 microns, less than 100 microns, less than 50 microns, or less than 25 microns prior to formation of the non-planar features. thinned. Thinning the substrate may be performed by at least one of lapping, grinding, polishing, chemical-mechanical polishing, dry etching, and wet etching. In some embodiments, substrate 101 is completely removed from the device.

Figures 18A-22E mainly show dies with rectangular or square perimeters. In other embodiments, the die has a triangular, trapezoidal, or hexagonal perimeter. In still other embodiments, at least a portion of the edge of the die is curved, eg, following a circular or elliptical contour. Other perimeters are possible and within the scope of the invention. In some embodiments, one or more electrical connections to the die are additionally or alternatively made to the top or bottom surface at one or more of the edges.

In some embodiments, one or more optical elements are used to spread the optical radiation exiting the optical fiber along at least one dimension before entering the photodiode. Such a configuration may be advantageous, for example, to reduce the maximum carrier density in the region of the absorbing layer near the position where optical radiation impinges on the photodiode, reducing the degree of non-radiative Auger recombination and It can increase the efficiency of diodes and optical systems.

31A-31E are schematic side, cross-sectional, and top views of photodiodes designed and packaged for lateral illumination through the corners or edges of light guide 3190 through optical coupling member 3187. , and a bottom view. FIG. 31A is a side view of a packaged photodiode optically coupled to an optical fiber 3180 taken along the dashed line shown in FIG. 31C. FIG. 31B is a cross-sectional side view of the packaged photodiode taken along the dashed line shown in FIG. 31C. FIG. 31C is a top view of the packaged photodiode taken along the dashed lines shown in FIG. 31A. FIG. 31D is a top cross-sectional view of the packaged photodiode taken along the dashed lines shown in FIG. 31A. FIG. 31E is a bottom view of the packaged photodiode looking at the dashed line shown in FIG. 31A.

31A-31E, in one embodiment, an optical waveguide 3190 or light pipe having a low optical absorption coefficient at a given wavelength is optically connected to both the optical fiber 3180 and the photodiode die 1002 of the photodiode package. to spread the light radiation emitted from the optical fiber 3180 laterally (i.e., in the Y direction) to make the light radiation intensity uniform in the device cavity region 1669, and to provide a comparative example without the optical waveguide 3190. design allows for higher efficiency for a given optical power.

The optical fiber 3180 includes a fiber core 3183 and a fiber cladding 3181, in close proximity to one edge of the photodiode die 1002 of the packaged photodiode and fixed portion as is known in the art. (eg, fixation portion 3601 of FIG. 36). Optical fiber 3180 includes a major axis 3181A that is the central axis of fiber core 3183, which emits radiation from illumination output end 3182 of optical fiber 3180, often referred to herein as the first end. It is often referred to herein as a reference for direction. Referring to FIG. 31B, in one example major axis 3181A is parallel to the X-axis. The fiber core 3183 comprises or consists of silica, glass, or plastic, and the fiber cladding 3181 is an optical fiber material, such as glass or plastic, for confining optical radiation by total internal reflection as is conventionally known. It may comprise or consist of a dielectric composition having a lower refractive index than core 3183 . At one location on the edge of the photodiode die 1002 , the edge can be coated with an anti-reflection optical window layer 911 and the rest of the periphery can be coated with an edge reflective layer 905 . Photodiode die 1002 can be attached to one or more of lower heat sink 901 or upper heat sink 909 . A heat sink may include a layer including at least one of copper, aluminum, etc., and/or a plate or other shape. Photodiode die 1002 may be attached to heat sink 909 by one of Au/Sn eutectic, Au/Ge eutectic, or similar bonding layers. In a preferred embodiment, optical coupling member 3187 is highly transparent at one or more wavelengths of radiation absorbed by the absorbing layer of photodiode die 1002 . In some embodiments, the optical coupling member 3187 is silica glass, borosilicate glass, aluminosilicate glass, high index glass, other glass compositions, _sapphire , quartz, zinc oxide, _MgAl2O4 spinel, other crystal compositions. material, polycarbonate, polymethyl methacrylate, or other polymer compositions. In some embodiments, one or more surfaces of optical coupling member 3187 are coated with reflective film 3185 . The reflective _film 3185 _is made of silver, gold, platinum, nickel, aluminum, or _TiO2 , _Ta2O5 , ZrO2 _{, SiO2} , _SiOx , _SiNx , _{Si3N4 , SiOxNy} , _Al2O . ₃ or one or more dielectrics such as MgF ₂ . The reflective film 3185 has greater than 85%, greater than 90%, greater than 95%, greater than 98%, or greater than 99% reflectivity at preselected wavelengths absorbed by the absorbing layer. at one or more wavelengths. In some embodiments, one or more wavelengths of radiation are in the range between 400 nm and 550 nm. The entrance aperture 3189 and one or more of the surfaces of the optical coupling member 3187 facing the photodiode die can be coated with an anti-reflective coating. The antireflective coating comprises a material selected from the group comprising _MgF2 , _SiO2 , _Al2O3 , _HfO2 , _LaTiO3 , _Si3N4 , _{or TiO2} , and is deposited by electron beam _deposition , sputtering, or , may be deposited by any other suitable deposition technique.

31A, 31B, optical radiation provided from optical fiber 3180 is significantly diffused into device cavity region 1669 (FIG. 31B) of photodiode die 1002 in the Z direction perpendicular to the semiconductor layers of the photodiode. at an angle selected to allow for high reflectivity from the reflective layer, as determined by the placement of the optical coupling member 3187, and multiple passes through the absorbing layer for efficient light absorption. , are combined. As described herein, the device cavity region 1669 includes an active region that includes one or more semiconductor layers 915, such as one or more of a non-absorbing portion, an absorbing portion, and a p-type connected semiconductor layer, and a substrate. 101 included. 31C, 31D, optical radiation is significantly emitted from optical fiber 3180 into device cavity region 1669 of photodiode die 1002 in a direction parallel to the edges of semiconductor layer 915 of photodiode die 1002 (i.e., the Y direction). and is determined by the placement and shape of the optical coupling member 3187 to allow significant lateral diffusion, reduced carrier density in regions of the absorption layer near entrance aperture 3189, and high conversion efficiency. at an angle selected to

In an alternative embodiment, the entrance aperture 3189 is convex in the vertical direction (i.e., in the Z direction (not shown)) to collimate or slightly focus the light radiation vertically and laterally. It is concave in the direction (ie Y-direction (not shown)) and is chosen to spread the light radiation more steeply laterally. In some embodiments, a bend is added to the radiation output end 3182 of the optical fiber 3180 to change the angular distribution of the output radiation. In some embodiments, optical coupling member 3187 and/or photodiode die 1002 are non-rectangular in the XY plane. In some embodiments, the edges of optical coupling member 3187 and/or photodiode die 1002 are non-linear. Depending on photodiode parameters such as substrate absorption coefficient, substrate refractive index, active region effective absorption coefficient and thickness, reflectivity of n and p junctions, edge reflectivity, etc., the optimum design will be reached. The material of the optical coupling member 3187 may be chosen to be very close to the refractive index of the device cavity region 1669, in which case the antireflection optical window layer 911 deposited over the optical window 912 is can become unnecessary.

In another set of embodiments, as shown schematically in FIG. 32, optical radiation is coupled from fiber core 3183 to photodiode die 1002 by integrating sphere 3293 . Optical radiation enters cavity 3291 of integrating sphere 3293 through entrance aperture 3189 and may strike antireflection optical window layer 911 of optical window 912 located at the entrance to device cavity region 1669 . In some embodiments, integrating sphere 3293 has a shape that is part of a sphere, ellipsoid, paraboloid, or other non-spherical shape. Optical radiation from device cavity region 1669 passes through semiconductor layer 915 and substrate 101, if present, is reflected from p-side reflective electrical connection 113, and exits device cavity region 1669, It hits the inner surface 3294 of the integrating sphere 3293 . In some embodiments, reflections off inner surface 3294 of integrating sphere 3293 are diffused by incorporated coatings, surface roughness, surface features, or other light distribution features. In some embodiments, inner surface 3294 of integrating sphere 3293 is coated with a diffusely reflective portion that can comprise or consist of titania (TiO ₂ ). In some embodiments, substrate 101 is removed, eg, as schematically shown in FIG. 14B. In some embodiments, such as that shown schematically in FIG. 32, the optical cavity region includes both device cavity region 1669 and cavity 3291 .

In certain embodiments, the shape of entrance aperture 3189 and integrating sphere 3293 are selected such that light entering cavity 3291 is reflected from inner surface 3294 of integrating sphere 3293 before striking anti-reflection optical window layer 911. . In some embodiments, opening 3189 includes or consists of a transparent window that can include an anti-reflective coating (not shown). In some embodiments, cavity 3291 is filled with a clear liquid or gas rather than air. In some embodiments, the transparent liquid or gas comprises or consists of one or more of silicones, epoxies, perfluorinated compounds, and polymers. In some embodiments, cavity 3291 is maintained at sub-atmospheric pressure to avoid scattering of optical radiation. In one embodiment, the photodiode is flip-chipped to form the n-side electrical connection through the n-type connection 1614, as schematically illustrated in more detail in FIGS. 17A and 17B.

In another set of embodiments, optical radiation of one or more wavelengths provided from an optical fiber is directed through a transparent n-side electrical connection, such as the n-side reflective electrical connection 3317 shown schematically in Figures 33A-33I. through an opening. 33A-33I are simplified side views of photodiodes designed and packaged for illumination through the surface of photodiode die 1002 that include n-side reflective electrical connections. Referring to FIG. 33A, in one embodiment, device cavity region 1669 of photodiode die 1002 consists of or includes substrate 101 and semiconductor layer 915 . Optical cavity region 3301 can include device cavity region 1669, as described below. In some embodiments, such as those schematically illustrated in FIGS. 13C, 14B, substrate 101 is removed and device cavity region 1669 consists of p-type layer 111, second non-absorbing layer 109, absorbing layer 105, and a semiconductor layer 915 such as the n-type non-absorbing layer 103 bonded to the p-type reflective connection 113 or the p-side reflective layer 1315, but without a separate light-transmitting member (FIG. 14B). sell. Photodiode die 1002 may include an n-side reflective electrical connection 3317 and a dielectric layer 3319 disposed on the surface of photodiode die 1002 . In preferred embodiments, the n-side reflective electrical connection 3317 is greater than 50%, or greater than 75%, in a plane parallel to the plane of the photodiode die 1002 that contains the n-side electrical connection (eg, the XY plane). or has a grating structure with an open area of more than 80%, or more than 90%, or more than 95%, and has high reflectivity. The opening formed in the n-side reflective electrical connection 3317 is filled with a dielectric layer 3319, which may consist of or include an anti-reflective coating. The optical coupling member 3187 has a reflective coating 3185 covering most of its periphery, and anti-reflective coatings are disposed over the entrance aperture 3189 and the exit aperture 3388 . Optical coupling member 3187 may have a conical, square pyramidal, square pyramidal, triangular pyramidal, hexagonal pyramidal, cubic, prismatic, spherical, ellipsoidal, parabolic, or other similar shape. sell. Optical radiation from optical fiber core 3183 can be focused into the entrance aperture of optical coupling member 3187 by fiber coupling lens 3390 . One or both of the large area surfaces of the fiber coupling lens 3390 can be covered with an antireflection coating 3391 (eg, _MgF2 ). In some embodiments, an antireflection coating 3392 is present on the output end of fiber core 3183 . 33A, optical coupling member 3187 functions as part of optical cavity region 3301, including device cavity region 1669, where optical radiation incident through entrance aperture 3189 is absorbed Reflected many times during light absorption in layer 107 , the optical radiation passes through dielectric layer 3319 and exit aperture 3388 many times. Similarly, optical radiation (e.g., luminescence) emitted within the absorbing layer 107, i.e., electrons and holes, are separated and collected by the p-side reflective electrical connection 113 and the n-side reflective electrical connection 3317. If not, but radiatively recombine, they can be reflected many times in the optical cavity before being reabsorbed in the absorbing layer 107 (so-called photon recycling). The use of a fiber coupling lens 3390 allows the optical radiation from the optical fiber core 3183 to be focused into a region of area smaller than the cross-sectional area of the fiber core, making the entrance aperture 3189 relatively small and Outward loss of reflection or luminescence light radiation through entrance aperture 3189 can be minimized. If the medium between the fiber coupling lens and the focusing plane has an index of refraction of 1, the area of the focused region can be reduced by a factor of NA ⁻² with respect to the area of the fiber core, provided that NA is the numerical aperture of the optical fiber.

Variations of this approach are also possible in which optical radiation is coupled to the photodiode die 1002 through the n-side reflective electrical connection 3317 rather than the optical windows 912, 1119 at the edge or top surface of the device. For example, an index-matched transparent adhesive 3394 may be provided between the optical coupling member 3187, the n-side reflective electrical connection 3317, and the dielectric layer 3319, as shown schematically in Figures 33B-33E. A fiber coupling lens 3390 may be provided on the end of the optical fiber core 3183, as shown schematically in Figure 33C, rather than as a separate element. As shown schematically in Figures 33D, 33E, the fiber coupling lens 3390 may be omitted. Optical radiation passes from the optical fiber core 3183 to the entrance aperture 3189 either through an index-matched transparent adhesive 3394 as shown schematically in FIG. It can pass through the antireflection coating 3392 on the end of the fiber core 3183 . In an alternative embodiment, optical radiation may be coupled to the photodiode die 1002 through the opening of the p-side reflective electrical connection rather than through the opening of the n-side reflective electrical connection.

Rather than coupling the optical radiation from the optical fiber 3180 into a relatively large area area through multiple openings in the n-side reflective electrical connection 3317 as in FIGS. Optical radiation can be coupled into the photodiode entrance aperture 3396 of the n-side reflective electrical connection 114 as schematically shown in FIG. Photodiode entrance aperture 3396 may be coated with an anti-reflection layer (not shown) similar to anti-reflection optical window layer 911 of optical window 912 described with respect to FIGS. 18A-22E. In these embodiments, optical cavity region 3301 includes device cavity region 1669 but does not include an external integrating optical cavity. In a preferred aspect of this embodiment, device cavity region 1669 includes at least one of a substrate or a light transmissive member, as described above. Optical radiation from the optical fiber core 3183 is directed into the photodiode entrance aperture 3396 either as a free-standing element (FIG. 33F) or through a fiber coupling lens 3390 connected to the end of the optical fiber core 3183 (FIG. 33G). You can focus depending on the Instead, light radiation from the optical fiber core 3183 is passed through an antireflection coating 3392 (FIG. 33H) on the end of the optical fiber core 3183 or through an index-matched transparent adhesive 3394 (FIG. 33I). can be coupled directly to the entrance aperture 3396 through the . In some embodiments, the area of the optical window or photodiode entrance opening on the edge of the photodiode die 1002 is between about 1% and about 20%, or 2% of the area of the edge of the photodiode die 1002. and about 10%.

In yet another set of embodiments, as shown schematically in FIGS. 34A-34I, optical radiation is transmitted from optical fiber 3180 to optical window 912 on the edge of photodiode die 1002 using additional optical elements. connected. In one or more of the embodiments disclosed herein, the area of optical window 912 can be between about 1 percent and about 20 percent of the surface area of the edge of photodiode die 1002 . In one or more alternative embodiments, the area of the optical window 912 is greater than 20 percent, such as greater than 50 percent of the surface area of the edge or face of the photodiode die 1002, or between 50 and 100 percent. or even between 80 and 99.9 percent. 34A-34I are side cross-sectional views that simply illustrate a photodiode designed and packaged for illumination through the edge of the photodiode die 1002. FIG. Referring to FIG. 34A, similar to FIGS. 31A-E, device cavity region 1669 includes substrate or light transmissive member 3401 and semiconductor layer 915 (not shown). Photodiode die 1002 may include an n-side reflective electrical connection 114 and a p-side reflective electrical connection 113 . The optical coupling member 3187 has a reflective coating 3185 covering most of its perimeter and anti-reflective coatings on the entrance aperture 3189 and the exit aperture 3388 . Optical coupling member 3187 may have a conical, square pyramidal, square pyramidal, triangular pyramidal, hexagonal pyramidal, cubic, prismatic, spherical, ellipsoidal, parabolic, or other similar shape. sell. Optical radiation from the optical fiber core 3183 is focused by a fiber coupling lens 3390 into the entrance aperture 3189 of the optical coupling member 3187 and then in the optical transmission member 3401 an optical window which may include an antireflection optical window layer 911. It may enter through 912 . One or both of the large area surfaces of the fiber coupling lens 3390 may be covered with an antireflection coating 3391 . In some embodiments, an antireflection coating 3392 is present on the radiation output end of fiber core 3183 . In the embodiment described by FIG. 34A, the optical coupling member 3187 along with the substrate or device cavity region 1669 allows optical radiation incident through the entrance aperture 3189 to be optically absorbed within the absorption layer 107 (not shown). It functions as part of the optical cavity region 3301 that is reflected many times during the Similarly, optical radiation emitted within the absorbing layer 107 is thus radiatively recombinated rather than electrons and holes being separated and collected by the p-side reflective electrical connection 113 and the n-side reflective electrical connection 114 . If so, it can be reflected many times in the optical cavity before being reabsorbed in the absorbing layer 107 (so-called photon recycling). The use of a fiber coupling lens 3390 allows the light radiation from the optical fiber core 3183 to be focused into a small area area, making the entrance aperture 3189 relatively small and passing through the entrance aperture 3189. It is possible to minimize the outward loss of reflected light radiation.

A variation of this approach is also possible in which optical radiation is coupled into the photodiode die 1002 through an optical window 912 on the edge of the photodiode die 1002 . For example, an index-matched clear adhesive 3394 may be provided between the optical coupling member 3187 and the optical window 912, as shown schematically in FIGS. 34B-34E. The fiber coupling lens 3390 may be provided on the end of the optical fiber core 3183, as shown schematically in Figure 34C, rather than as a separate element. As shown schematically in Figures 34D, 34E, the fiber coupling lens 3390 may be omitted. Optical radiation passes from the optical fiber core 3183 to the entrance aperture 3189 either through an index-matched transparent adhesive 3394 as shown schematically in FIG. Additionally, it can pass through the antireflection coating 3392 on the end of the fiber core 3183 .

Rather than coupling the optical radiation from the optical fiber 3180 into a relatively large area at the edge of the photodiode die 1002 as in FIGS. Radiation can be coupled into the photodiode entrance aperture 3396 . In some configurations, the edge of photodiode die 1002 includes a photodiode entrance opening 3396 surrounded by edge reflective layer 905 . Photodiode entrance aperture 3396 may be coated with an anti-reflection layer (not shown) similar to anti-reflection optical window layer 911 of optical window 912 described with respect to FIGS. 18A-22E. In these embodiments, optical cavity region 3301 includes device cavity region 1669 but does not include an external integrating optical cavity. In some preferred aspects of this embodiment, device cavity region 1669 includes at least one of a substrate or a light transmissive member, as described above. In an alternative aspect of this embodiment, as shown schematically in Figures 27A, 27B, the optical cavity region 3301 includes the second light transmissive member 2101 but includes the substrate 101 or the first light transmissive member. or not. Optical radiation from the optical fiber core 3183 is directed into the photodiode entrance aperture 3396 either as a free-standing element (FIG. 34F) or through a fiber coupling lens 3390 connected to the end of the optical fiber core 3183 (FIG. 34G). It can be focused depending on the Instead, the optical radiation from the optical fiber core 3183 is directed through an antireflection coating 3392 on the end of the optical fiber core 3183 (Fig. 34H) or through an index-matched transparent adhesive 3394 (Fig. 34I). can be coupled directly to entrance aperture 3396 through .

In some embodiments, packaged photodiodes that can convert some, but not all, of the incident optical radiant energy from the fiber to electrical power are desirable. A schematic cross-sectional view of a photodiode assembly 2301 designed to extract only a portion of the incident optical radiant energy produced by a laser diode or optical fiber 2401 is shown in FIG. 23A. In one embodiment, as shown in FIG. 23A, the photodiode assembly 2301 includes a reflective edge layer 1404, but light emission from the fiber is directed to the top surface of the photodiode die (or in some alternative configurations). to the bottom surface), through the p-type connection 1111, the semiconductor layer 915, the light-transmitting member (e.g., the substrate 101), and then through the output optical window 1412 to another adjacently arranged similarly configured fiber (not shown). ). A number of such photodiode assemblies may be arranged in series, such as vertically stacked, as shown in FIG. 23B. In some embodiments, multiple photodiode assemblies in series have approximately the same peak absorption wavelength as determined by the indium composition of the absorbing layers. In an alternative embodiment, the photodiode assembly is configured to absorb different wavelengths of optical radiation, eg, by varying the indium composition in each absorbing layer.

As noted above, nitride-based packaged photodiodes operating in the visible wavelengths are expected to have advantages over arsenide-based packaged photodiodes operating in the infrared region. FIG. 26 schematically shows comparative efficiency as a function of bandgap energy, including energies for nitride-based and arsenide-based packaged photodiodes. In the detailed balance limit of a packaged power photodiode operating under non-degenerate conditions, we assume that the input photon energy is slightly above the bandgap, with 100% optical absorption, and 100% external quantum efficiency. , Shockley and Queisser, Journal of Applied Physics 32, 510 (1961). For simplicity of explanation, the input power was assumed to be 0.1 W and the area of the optical window was assumed to be 10 ⁻⁵ m ² , but similar results were obtained for a wide range of values of these parameters. is expected. In one embodiment, the packaged photodiode is used generally at room temperature. As shown in FIG. 26, at a temperature of 300 Kelvin (room temperature), the theoretical marginal efficiency is 78.2% for a GaAs photodiode operating at a wavelength of 880 nm, but operating at a wavelength of 450 nm. 86.5% for the InGaN photodiodes that do. The higher bandgap of InGaN compared to GaAs results in higher efficiency due to the nature and shape of the Planckian distribution. However, in some embodiments, the photodiodes are used at high temperatures, such as 400 Kelvin, 500 Kelvin, or 600 Kelvin, or even higher. At a temperature of 400 Kelvin, the theoretical marginal efficiency is 71.2% for GaAs photodiodes operating at a wavelength of 880 nm, but 82.0% for InGaN photodiodes operating at a wavelength of 450 nm. is. Although the absolute value of efficiency is lower at higher temperatures, the relative efficiency advantage of InGaN photodiodes over GaAs photodiodes increases from +10% to +15%. At a temperature of 500 Kelvin, the theoretical marginal efficiency is 64.2% for GaAs photodiodes operating at a wavelength of 880 nm, but 77.6% for InGaN photodiodes operating at a wavelength of 450 nm. is. Although the absolute value of the efficiency is lower, the relative efficiency advantage of the InGaN photodiode compared to the GaAs photodiode further increases to +21%. At a temperature of 600 Kelvin, the theoretical marginal efficiency is 57.4% for GaAs photodiodes operating at a wavelength of 880 nm, but 73.2% for InGaN photodiodes operating at a wavelength of 450 nm. is. Although the absolute value of the efficiency is lower, the relative efficiency advantage of the InGaN photodiode over the GaAs photodiode further increased to +28%.

At least one packaged nitride-based power photodiode can be incorporated into the fiber optic feeding module. As shown schematically in FIGS. 24A-24C, the fiber optic feeding module includes at least one laser diode 2401 and an optical fiber 2402 that is also connected to at least one laser diode 2401 and at least one photodiode 2403. Including at least part of. In some embodiments, optical fiber 2402 comprises a fiber optic bundle. In one embodiment, the fiber optic feeding module includes only one laser diode 2401, one optical fiber 2402, and one photodiode 2403 (FIG. 24A). In some embodiments, the optical fiber 2402 (or fiber optic bundle) has one or more branches, and different optical fiber sections are connected to different photodiodes 2403 (FIG. 24B). In some embodiments, the fiber optic feeding module includes one or more optical distribution devices 2404, each capable of transmitting a portion of the controlled optical power to at least two output optical fiber branches. (Fig. 24C). In some embodiments, the optical distribution device 2404 includes at least one of one or more galvanometer mirrors, one or more microscan mirrors, one or more focusing lenses, and one or more optical beam splitters. Contain or consist of.

In some embodiments, the fiber optic feeding module is designed solely to transmit power optically. In other embodiments, as shown schematically in Figures 25A-25D, the fiber optic feeding module is designed to transmit both power and signal. For example, the signal can be superimposed on the optical power by modulating the amplitude of the laser diode 2401 at one or more frequencies. In some embodiments, the control module modulates the power output from the laser diode with at least one controlled AC frequency and converts the photodiode signal into a DC power component and the at least one controlled frequency. of AC signal components. The amplitudes of the modulated AC components of the modulated laser diode power and photodiode power can be less than 10%, less than 1%, or less than 0.1% of the corresponding DC components. A first photodiode configured to convert the DC power component to electrical power is further configured to detect the at least one controlled frequency AC signal component. In some embodiments, a separate signal photodetector device is provided, the separate signal photodetector device configured to detect at least one AC signal component at the controlled frequency.

An amplifier system connected to the photodiode then picks up the signal or signals at one or more frequencies. In one embodiment, the fiber optic feeding module includes at least two laser diodes 2401, 2405 and at least two photodiodes 2403, 2404, configured to allow signal communication in at least two different directions (Fig. 25C). In some embodiments, the signal is modulated at an audible frequency and the output is coupled to an audio device such as headphones or speakers. In one embodiment, the AC signal component is modulated at an audio frequency and the module is connected to headphones or audio speakers. In some embodiments, the signal is modulated at frequencies in kilohertz, megahertz, or gigahertz (FIG. 25D).

In one embodiment, the modulated signal is detected using the same GaN-based photodiode device that also converts optical power to electrical power. In an alternative embodiment, a separate signal photodetector device is used to convert a portion of the modulated optical signal to a modulated electrical signal. In some embodiments, the separate signal photodetector device is selected from GaN-based photodiodes, Si-based photodiodes, avalanche photodiodes, InGaAs-based photodiodes, and InP-based photodiodes. In some embodiments, the separate signal photodetector device is edge-coupled or incorporates a resonant cavity region or refractive facets. In some embodiments, the separate signal photodetector device has a bandwidth of at least 1 MHz, at least 10 MHz, at least 100 MHz, at least 1 GHz, at least 10 GHz, at least 25 GHz, or at least 100 GHz. In one embodiment, a separate signal photodetector device is mounted in the same optical cavity region from which the GaN-based photodiode receives DC optical power and receives the modulated optical signal therefrom. In one embodiment, a separate signal photodetector device receives the signal from an optical fiber connected to the same network as the GaN-based power photodiode. In one embodiment, a separate signal photodetector device is optically isolated from the GaN-based power photodiode so that stray light emitted from the latter does not degrade the bandwidth of the former. In one embodiment, a small portion of the optical radiation from the optical fiber is directed to a separate photodetector device and most of the remaining optical radiation is directed to a GaN-based power photodiode.

35A-35F are side cross-sectional views that simply illustrate a packaged photodiode and separate signal photodetector device 3595 connected to an optical fiber according to embodiments of the present disclosure. In some embodiments, optical radiation emitted from optical fiber 3180 passes through signal photodetector device 3595 before being directed by fiber coupling lens 3390 to photodiode die 1002, as shown schematically in FIG. 35A. is reflected to entrance aperture 3189 of optical coupling member 3187 . In some embodiments, the signal photodetector device 3595 has a highly reflective coating 3596 that allows only a small portion of the incident optical radiation to pass to the signal photodetector device 3595 . In some embodiments, the reflectivity of highly reflective coating 3596 is greater than 90%, greater than 95%, greater than 97%, or greater than 98%. In some embodiments, highly reflective film 3596 includes one or more of a metal, such as silver, and a dielectric.

In one embodiment, a second fiber coupling lens 3390 is used to focus the optical radiation from the optical fiber 3180 onto the signal photodetector device 3595 (FIG. 35B), resulting in a small lateral A directional dimension can be used, reducing the capacitance of the latter and increasing the bandwidth. In some embodiments, the lateral dimension of signal photodetector device 3595 is less than 1 millimeter, less than 300 microns, less than 200 microns, less than 100 microns, or less than 50 microns. In one embodiment, the signal photodetector device 3595 samples optical radiation through an opening 3598 in the reflective film 3185 on the optical coupling member 3187, as shown schematically in FIGS. 35C-35F. In one embodiment, a small internal reflector 3597 contained within optical coupling member 3187 reflects a portion of the optical radiation toward opening 3598 . In some embodiments, internal reflector 3597 includes one or more of a metal, such as silver, and a dielectric. In some embodiments, internal reflector 3597 comprises a bubble or void within optical coupling member 3187 . In some embodiments, the maximum dimension of internal reflector 3597 is less than about 2 millimeters, less than about 1 millimeter, less than about 500 microns, less than about 200 microns, less than about 100 microns, or less than about 50 microns. be.

In one embodiment, optical radiation emitted from optical coupling member 3187 is incident on the edge of photodiode die 1002 (FIG. 35C). In another embodiment, optical radiation emitted from optical coupling member 3187 enters photodiode die 1002 through an opening in n-side reflective electrical connection 3317 (FIGS. 35D-35F). In one embodiment, optical radiation from optical fiber 3180 is focused by fiber coupling lens 3390 into entrance aperture 3189 of optical coupling member 3187 (FIGS. 35C-35E). In some embodiments, index-matched adhesive 3394 is used to direct optical radiation from optical coupling member 3187 to photodiode die 1002 (FIGS. 35E, 35F) or from optical fiber 3180 to entrance aperture 3189 (FIGS. 35E, 35F). Figure 35F).

In some embodiments, the fiber optic powered module operates near room temperature, ie below about 400 Kelvin. In other embodiments, the fiber optic feeding module operates at temperatures between about 400 Kelvin and about 500 Kelvin, between about 500 Kelvin and about 600 Kelvin, or above about 600 Kelvin.

In some embodiments, the optical coupling between the optical fiber and the photodiode can be non-rigid or non-contacting, allowing the optical power to be easily coupled into the rotating object.

In one embodiment, power from the photodiode is used to power an Internet of Things (IoT) sensor or actuator. In some embodiments, power from the photodiode is used to power a personal electronic application or device.

In alternative embodiments, transmission of optical power from a light source, such as a laser diode, to a photodiode is done without fiber, e.g., between satellites in space, or between ground and airborne drones. .

In one embodiment, the fiber optic feeding module is integrated with the illumination system 2407, as shown schematically in FIG. Illumination system 2407 may include one or more of phosphors, heat sinks, reflective or transmissive optics that form a far-field distributed light, sensors, and control systems. Such capability is possible with light sources (eg, laser diodes) 2401 and photodiode systems based on nitride semiconductor material systems, but not with arsenide-based systems, for example. A portion of the light injected through an optical fiber 2402 by a light source such as a laser diode 2401 is converted into electrical power by a photodiode 2403 and the remaining light is coupled out into another optical fiber 2406 for illumination. Injected into system 2407 . In some embodiments, lighting system 2407 is a lighting fixture. In some embodiments, lighting system 2407 is an automobile headlight. In some embodiments, the luminaire includes one or more phosphors to convert a portion of the light from the optical fiber having one or more wavelengths, e.g., between 400 nanometers and 460 nanometers. emit green, yellow and/or red light. In some embodiments, the lighting fixture emits light that approximates the solar spectrum. In some embodiments, the lighting fixture emits light having a color temperature of about 2700 Kelvin, about 3000 Kelvin, about 4000 Kelvin, or about 6000 Kelvin. In some embodiments, the lighting fixture emits light having a color rendering index (CRI) of about 80, between 80 and 90, between 90 and 95, or greater than 95. In some embodiments, the luminaire emits collimated light having a cone angle of less than 45 degrees, less than 30 degrees, less than 20 degrees, less than 10 degrees, less than 5 degrees, or less than 3 degrees. In some embodiments, power from the photodiode 2403 is used to power components of the lighting fixture, such as sensors or wireless communication devices. In one embodiment, power from photodiode 2403 is used to power a control system that varies the output characteristics of the lighting system, such as color temperature, intensity of blue light relative to intensity of other colors, and angular distribution of light. .

One or more fiber optic feeding modules may be incorporated into a fiber optic feeding system. In addition to at least one laser diode light source, at least one power photodiode, and at least a portion of the optical fiber, the fiber optic power supply system may include a control system, leads to a power source such as a battery, an alternator, or a mains power source. An AC or DC power supply, a flexible jacket surrounding at least a portion of the optical fiber, at least one temperature sensor, at least one for maintaining the position of at least one element of the fiber optic feeding module relative to the structure in which it is located. It may include one or more of a single harness member, cooling means such as a fan or flowing coolant, and at least one sensor. Fiber optic feeding systems can be used in automobiles, in automobile engines, in trucks or truck engines, in buses or bus engines, in locomotives, in aircraft or aircraft engines, in helicopters or helicopter engines, in houses, apartments or residential buildings. , or may be located within a commercial facility building.

In embodiments such as fiber optic feeding systems in automobiles or rooms in buildings, the length of the fiber is relatively short, between about 1 centimeter and about 1 meter. In such cases, optical attenuation within the fiber does not limit performance, and other factors such as bend radius and thermal stability may be more important. In other embodiments where optical power is transmitted from one room to another, such as a fiber optic feed system in a building, the fiber length can be between 1 and 100 meters. In this case, optical attenuation within the fiber may be more important and bend radius less important. In other embodiments, the fiber length can be between 100 meters and 1 kilometer, or greater than 1 kilometer.

Fiber optic feeding systems may have improved reliability compared to other systems. For example, compared to conventional wire feed systems, the connections (optical, as opposed to electrical connections) are less susceptible to oxidation or other degradation, and may eliminate electrical transmission noise caused by current flow. Compared to arsenide-based systems, nitride-based systems may have longer operating lifetimes and be less susceptible to high temperature excursions.

As described above, the primarily lateral propagation of light within the device cavity region of the photodiode allows deposition of a relatively thin absorbing layer on a relatively thick substrate to increase the light intensity within the device cavity region. part can be absorbed. To quantify the trade-offs between various design parameters of the photodiode, we calculated the absorption in the substrate, the non-absorbing layer, the absorbing layer, and the top and bottom reflective connections for the device cavity area. A light absorption model was constructed to illustrate. Inputs to the model include the absorption coefficients, refractive indices, and thicknesses of the substrate and absorbing layers, and the reflectance of the top and bottom reflective connections. With these inputs, light absorption can be calculated as a function of light propagation angle with respect to the plane of the absorbing layer. By way of example, Figures 29A, 29B show the cumulative optical absorption of the substrate, absorber layer, top p-connected mirror, and bottom p-connected mirror as a function of lateral propagation distance, along with the input parameters used in this calculation. there is A light propagation angle of 15 degrees maximized light absorption within the absorbing layer for the set of parameters shown in FIG. 29A.

Embodiments of the present disclosure are further described with reference to the following comparative examples and illustrative process examples. It will be apparent to those skilled in the art that many changes, both to materials and methods, may be practiced without departing from the scope of the disclosure.

Comparative example 1
As a comparison, a +c-face, GaN-on-GaN die was taken from a commercial LED emitting at about 405 nm and used as a photodiode. The LED structure is believed to include an AlGaN electron blocking layer under a p-type GaN layer, and a multiple quantum well MQW structure including InGaN well layers and GaN barrier layers. The LED structure is believed to contain neither highly doped layers nor doped reduced bandgap layers immediately adjacent to the MQW layers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. The results are shown in FIG. 5 as the "LIV" curve. From the measurement results, V _oc was evaluated as 2.74 V, E _g =3.06 eV, I _sc =2.6 A/cm ² , eV _oc /E _g =0.89, and FF =46%. . The values of V _oc and I _sc are found to be relatively good, while the low fill factor values indicate the need for improved device design. On the other hand, a relatively high fill factor curve is shown in FIG. 5 for comparison.

Comparative example 2
500 nm n-doped GaN layer with Si dopant concentration of 2×10 ¹⁸ cm ⁻³ followed by 100 nm n-doped GaN layer with Si dopant concentration of 4×10 ¹⁸ cm ⁻³ , then an unintentionally doped absorber layer, then a 90 nm p-type doped layer containing Mg at a concentration of 1×10 ¹⁹ cm ⁻³ , then Mg at 1×10 ²⁰ cm ^{−3 .} Epitaxial structures containing a 10 nm p-type doped layer with a concentration of ³ were deposited on bulk GaN substrates miscut from (0001) to [10-10] at about 0.4 degrees. The absorber layer was unintentionally doped and consisted of 10 7 nm GaN layers followed by 10 alternating 4 nm In _0.14 Ga _0.86 N well layers and 7 nm GaN barrier layers. It consisted of The construction was characterized by an electroluminescence peak at approximately 447 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. FIG. 6 shows the results. From the measurement results, V _oc is evaluated as 2.32 V, E _g =2.77 eV, I _sc =6.5×10 ⁻³ A, eV _oc /E _g =0.84 and FF=33%. was. The values of V _oc and I _sc are found to be relatively good, while the low fill factor values indicate the need for improved device design.

Comparative example 3
1000 nm n-doped GaN layer with Si dopant concentration of 2.0×10 ¹⁸ cm ⁻³ followed by 30 nm n-doped GaN layer with Si dopant concentration of 2×10 ¹⁹ cm ⁻³ A GaN layer, then an unintentionally doped absorber layer, then a 50 nm p-type doped layer containing Mg at a concentration of 2×10 ¹⁹ cm ⁻³ , then Mg at 1×10 ²⁰ Epitaxial structures containing a 10 nm p-type doped layer with a concentration of cm ⁻³ were deposited on bulk GaN substrates miscut from (0001) to [10-10] at about 0.4 degrees. bottom. The absorber layer was unintentionally doped and consisted of a 40 nm double heterostructure In _0.13 Ga _0.87 N layer. The construction was characterized by an electroluminescence peak at approximately 435 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. The results are shown in FIG. From the measurement results, V _oc was evaluated as 2.43 V, E _g =2.85 eV, I _sc =0.013 A, eV _oc /E _g =0.85, and FF 38%. The values of V _oc and I _sc are found to be relatively good, while the low fill factor values indicate the need for improved device design.

Comparative example 4
A 1000 nm n-type doped GaN layer with a Si dopant concentration of 2.0×10 ¹⁸ cm ⁻³ followed by a 100 nm n-type GaN layer with a Si dopant concentration of 5.0×10 ¹⁷ cm ⁻³ . type-doped GaN layer, then an unintentionally doped absorber layer, then a 50 nm p-type doped layer containing Mg at a concentration of 2×10 ²⁰ cm ⁻³ , then Mg at 1× Epitaxial structures containing a 10 nm p-type doped layer with a concentration of 10 ²⁰ cm ⁻³ were fabricated on bulk GaN substrates miscut from (0001) to [10-10] by about 0.4 degrees. A film was formed. The absorber layer is unintentionally doped and consists of a 40 nm double heterostructure In _0.18 Ga _0.82 N layer. The construction was characterized by an electroluminescence peak at approximately 473 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. From the measurement results, V _oc was evaluated as 2.20 V, E _g =2.62 eV, eV _oc /E _g =0.84, and FF 45%. The values of _Voc are found to be relatively good, while the low fill factor values indicate the need for improved device design.

Example 1
A 1000 nm n-type doped GaN layer with a Si dopant concentration of 2.0×10 ¹⁸ cm ⁻³ followed by a 30 nm n-type GaN layer with a Si dopant concentration of 3.0×10 ¹⁹ cm ⁻³ . type-doped GaN layer, then an unintentionally doped absorber layer, then a 50 nm p-type doped layer containing Mg at a concentration of 3×10 ¹⁹ cm ⁻³ , then Mg at 1× Epitaxial structures containing a 10 nm p-type doped layer with a concentration of 10 ²⁰ cm ⁻³ were fabricated on bulk GaN substrates miscut from (0001) to [10-10] by about 0.4 degrees. A film was formed. The absorber layer is unintentionally doped and consists of a 40 nm double heterostructure In _0.13 Ga _0.87 N layer. The construction was characterized by an electroluminescence peak at approximately 435 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. From the measurement results, V _oc was evaluated as 2.43 V, E _g =2.85 eV, eV _oc /E _g =0.85, and FF 85%.

Example 2
1000 nm n-type doped GaN layer with Si dopant at an average concentration of 2.0×10 ¹⁸ cm ⁻³ followed by 30 nm n-type with Si at an average concentration of 4.0×10 ¹⁹ cm ⁻³ An epitaxial structure comprising a doped GaN layer, then an unintentionally doped absorber layer, and then a 50 nm p-type doped layer containing Mg at a concentration of 2×10 ²⁰ cm ⁻³ was prepared by (0001 ) to [10-10] on a bulk GaN substrate miscut at about 0.4 degrees. The absorber layer is unintentionally doped and consists of a 40 nm double heterostructure In _0.18 Ga _0.82 N layer. The structure is characterized by a photoluminescence peak at approximately 473 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. From the measurement results, V _oc was evaluated as 2.20 V, E _g =2.62 eV, eV _oc /E _g =0.84, and FF 91%.

Example 3
1000 nm n-type doped GaN layer with Si dopant at an average concentration of 2.0×10 ¹⁸ cm ⁻³ followed by 100 nm n-type with Si at an average concentration of 5.0×10 ¹⁷ cm ⁻³ A doped GaN layer followed by a compositional gradient with an initial composition of GaN and a final composition of typically In _0.18 Ga _0.72 N, with a Si dopant at a concentration of about 5.0×10 ¹⁷ cm ⁻³ . about 6 nm thick InGaN layer containing, then an unintentionally doped absorber layer, then a 50 nm p-type doped layer containing Mg at a concentration of 2×10 ²⁰ cm ⁻³ . The structures were deposited on bulk GaN substrates miscut from (0001) to [10-10] at about 0.4 degrees. The absorber layer is unintentionally doped and consists of a 40 nm double heterostructure In _0.18 Ga _0.82 N layer. The structure is characterized by a photoluminescence peak at approximately 473 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. From the measurement results, V _oc was evaluated as 2.20 V, E _g =2.62 eV, eV _oc /E _g =0.84, and FF 85%.

Example 4
A 300 nm n-type doped GaN layer containing Si dopants at an average concentration of 3.5×10 ¹⁸ cm ⁻³ , then an InGaN—GaN strained-layer superlattice (SLS), then an initial composition of generally In _0.04 Ga _0.96 N with a compositional gradient of typically In _0.2 Ga _0.8 N with a final composition of about 6 nm and containing a Si dopant at a concentration of about 4.0×10 ¹⁷ cm ⁻³ . A thick InGaN layer, then a 9-period multiplex including a 3-nm In _0.2 Ga _0.8 N well and a 9-nm GaN barrier layer containing a Si dopant at a concentration of about 3×10 ¹⁷ cm ⁻³ . A quantum well structure followed by an epitaxial structure comprising a 100 nm p-type doped layer containing Mg at a concentration of about 2×10 ²⁰ cm ⁻³ was deposited on a sapphire substrate with the plane normal of the substrate being nitrided. It was grown within 5 degrees of [0001] of the epitaxial layer. The absorber layer consisted of a 9-period multiple quantum well structure. The structure was characterized by a photoluminescence peak at approximately 457 nanometers. The reverse current-voltage characteristics of the fabricated devices were recorded under dark and bright conditions, but illuminated by a commercial 405 nm laser diode. The results are shown in FIG. From the measurement results, V _oc was evaluated as 2.34 V, E _g =2.71 eV, I _sc =0.0114 A, eV _oc /E _g =0.86, and FF 78%. It can be seen that the values of V _oc , I _sc and FF are relatively good. The measured FF is artificially low due to series resistance caused by the method of electrically probing the n-metal connection.

Example 5
1000 nm n-type doped GaN layer containing Si dopants at an average concentration of 1.0×10 ¹⁸ cm ⁻³ , then an unintentionally doped 2 nm In _0.18 Ga _0.82 N well, and a 20-period multiple quantum well structure containing 4 nm GaN barrier layers, followed by an epitaxial structure containing a 50 nm p-type doped layer containing Mg at a concentration of about 2×10 ¹⁸ cm ⁻³ , It was deposited on a bulk GaN substrate miscut at about 4 degrees from (000-1) to [10-10]. The absorber layer consisted of a 9-period multiple quantum well structure. The structure is characterized by a photoluminescence peak at approximately 470 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. From the measurement results, V _oc is estimated to be 2.20 V, E _g =2.63 eV, eV _oc /E _g =0.84, and FF 88%.

Example 6
A 1000 nm n-type doped GaN layer containing Si dopants at an average concentration of 5.0×10 ¹⁸ cm ⁻³ , then an unintentionally doped 2 nm In _0.18 Ga _0.82 N well and 20 periods of multiple quantum well structures containing 4 nm GaN barrier layers, then an epitaxial structure containing 100 nm p-type doped layers containing Mg at a concentration of about 1×10 ¹⁹ cm ⁻³ (30 -3-1) was deposited on a bulk GaN substrate having a crystal orientation within 0.1 degrees. The structure is characterized by a photoluminescence peak at approximately 470 nanometers. Reverse current-voltage characteristics were recorded under dark and bright conditions, but illuminated by a commercially available 405 nm laser diode. From the measurement results, V _oc was evaluated as 2.20 V, E _g =2.63 eV, eV _oc /E _g =0.84, and FF 88%.

While embodiments of the present disclosure have been described above, other and further embodiments of the present disclosure may be contemplated without departing from the basic scope of the present disclosure, and the scope of the present disclosure includes: It is defined by the appended claims.

101 substrate 105 n-type first non-absorbing layer 107 absorbing layer 109 second non-absorbing layer 111 p-type non-absorbing layer 113 p-side reflective electrical connection 114 n-side reflective electrical connection 215 discontinuous p-electrode 217 discontinuous n Electrode 252 light receiving surface

While embodiments of the present disclosure have been described above, other and further embodiments of the present disclosure may be contemplated without departing from the basic scope of the present disclosure, and the scope of the present disclosure includes: It is defined by the appended claims.
Hereinafter, preferred embodiments of the present invention will be described item by item.
Embodiment 1
In optical assemblies,
A first die comprising one or more absorbent layers disposed between a first non-absorbent layer and a second non-absorbent layer, the one or more absorbent layers and the first and second The two non-absorbing layers each comprise Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ¹⁰ cm ⁻² . a first die;
fixed part and
including
each said one or more absorbent layers having a thickness measured in a first direction and an absorbent layer surface oriented parallel to the first plane and perpendicular to the first direction;
The optical assembly has an optical cavity region with an optical window, the optical cavity region comprising:
a device cavity region comprising the one or more absorbing layers, the first non-absorbing layer, and the second non-absorbing layer;
at least two opposing reflective members configured to internally reflect electromagnetic waves incident through the optical window to pass through the device cavity region at least twice;
and
The optical assembly, wherein the fixture is configured to position a first end of an optical fiber a first distance from a surface of the optical window of the first die.
Embodiment 2
2. The optical assembly of embodiment 1, wherein the first distance is between about 2 microns and about 10 millimeters.
Embodiment 3
3. The optical assembly of embodiment 2, wherein the first distance is constant and has a tolerance of between about 1 micrometer and about 1 millimeter.
Embodiment 4
The optical fiber has a principal axis,
2. The optical assembly of embodiment 1, wherein an angle [alpha] between the principal axis of the optical fiber and the first plane is between zero and about 50 degrees.
Embodiment 5
2. The optical assembly of embodiment 1, wherein an angle γ between the principal axis of the optical fiber and the direction normal to the surface of the optical window is between zero and about 60 degrees.
Embodiment 6
2. The optical assembly of embodiment 1, wherein an angle β between the major axis of the optical fiber and the edge of the first die is between zero and about 60 degrees.
Embodiment 7
7. The optical assembly of embodiment 6, wherein said angle β is between zero and approximately 20 degrees.
Embodiment 8
2. The optical assembly of embodiment 1, wherein an angle γ between the principal axis of the optical fiber and the direction normal to the first plane is between about 0 and 60 degrees.
Embodiment 9
a mirror configured to reflect light radiation from a light source onto the surface of the optical window;
2. An optical assembly as recited in embodiment 1, further comprising.
Embodiment 10
a second die including an optical cavity region having an optical window;
further includes
The mirror reflects light radiation from the light source to the surface of the optical window of the first die and further reflects light radiation from the light source to the surface of the optical window of the second die. 10. An optical assembly according to embodiment 9, configured to:
Embodiment 11
2. The optical assembly of embodiment 1, wherein the optical cavity region comprises a first light transmissive member and a second light transmissive member optically connected to the first light transmissive member.
Embodiment 12
an optical coupling member disposed between the first end of the optical fiber and the optical window and configured to diffuse the optical radiation in a direction parallel to the surface of the optical window;
2. An optical assembly as recited in embodiment 1, further comprising.
Embodiment 13
an optical coupling member disposed between the first end of the optical fiber and the optical window and configured to diffuse the optical radiation in a direction parallel to the edge of the first die; ,
2. An optical assembly as recited in embodiment 1, further comprising.
Embodiment 14
an integrating sphere configured to couple optical radiation received from the first end of the optical fiber into the device cavity region of the first die;
2. An optical assembly as recited in embodiment 1, further comprising.
Embodiment 15
an optical coupling member disposed between the first end of the optical fiber and the optical window;
further includes
The optical window includes a reflective electrical connection having an aperture, and the optical coupling member is configured to diffuse the optical radiation in two orthogonal directions in the first plane. 3. The optical assembly of embodiment 1.
Embodiment 16
a fiber coupling lens disposed between the first end of the optical fiber and the optical coupling member;
16. The optical assembly of embodiment 15, further comprising.
Embodiment 17
a fiber coupling lens between the first end of the optical fiber and the optical coupling member;
17. The optical assembly of embodiment 16, further comprising.
Embodiment 18
The device cavity region further includes an n-side reflective electrical connection and a p-side reflective electrical connection, the optical window positioned in one of the n-side reflective electrical connection and the p-side reflective electrical connection. 2. The optical assembly of embodiment 1, which is a
Embodiment 19
The optical window includes a surface configured to receive the electromagnetic wave and is positioned on an edge of the first die, the area of the surface of the optical window being equal to the first 3. The optical assembly of embodiment 1, wherein the area of the edge of the die is between about 1% and about 20%.
Embodiment 20
a fiber coupling lens positioned between the first end of the optical fiber and the optical window;
20. The optical assembly of embodiment 19, further comprising.
Embodiment 21
In optical assemblies,
A first die comprising one or more absorbent layers disposed between a first non-absorbent layer and a second non-absorbent layer, the one or more absorbent layers and the first and second The two non-absorbing layers each comprise Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ¹⁰ cm ⁻² . a first die;
optical element and
including
each said one or more absorbent layers having a thickness measured in a first direction and an absorbent layer surface oriented parallel to the first plane and perpendicular to the first direction;
the first die having a device cavity region with an optical window;
The device cavity region includes at least two opposing reflective members configured to internally reflect electromagnetic waves incident through the optical window to pass through the one or more absorbing layers at least twice. includes
An optical assembly, wherein the optical element is configured to receive optical radiation from an optical fiber and transmit the received optical radiation to at least a portion of the optical window.
Embodiment 22
22. The optical assembly of embodiment 21, wherein the optical element comprises an optical waveguide or optical coupling member.
Embodiment 23
22. The optical assembly of embodiment 21, wherein the optical fiber includes a major axis and a radiation output end positioned a first distance from the surface of the optical window of the first die.
Embodiment 24
an optical fiber coupling lens positioned between the radiation output end of the optical fiber and the optical window;
22. The optical assembly of embodiment 21, further comprising.
Embodiment 25
The optical fiber has a principal axis,
22. The optical assembly of embodiment 21, wherein an angle [alpha] between the principal axis of the optical fiber and the first plane is between zero and approximately 50 degrees.
Embodiment 26
The optical fiber has a principal axis,
22. The optical assembly of embodiment 21, wherein an angle β between the principal axis of the optical fiber and the surface of the optical window is between zero and approximately 60 degrees.
Embodiment 27
The optical fiber has a principal axis,
22. The optical assembly of embodiment 21, wherein an angle β between the major axis of the optical fiber and the edge of the first die is between zero and about 60 degrees.
Embodiment 28
28. The optical assembly according to embodiment 27, wherein said angle β is between zero and about 20 degrees.
Embodiment 29
The optical fiber has a principal axis,
22. The optical assembly of embodiment 21, wherein an angle γ between the principal axis of the optical fiber and a direction normal to the first plane is between about 0 and about 60 degrees.
Embodiment 30
22. The optical assembly of embodiment 21, wherein the optical element is configured to spread the optical radiation in a direction parallel to the edge of the first die.
Embodiment 31
22. The optical assembly of embodiment 21, wherein the optical element is configured to spread the optical radiation in two orthogonal directions in the first plane.
Embodiment 32
In an optical device,
A die comprising one or more absorbent layers disposed between a first non-absorbent layer and a second non-absorbent layer, the one or more absorbent layers and the first and second non-absorbent layers. The absorber layers each comprise Al _x In _y Ga _1-x-y N, with 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ¹⁰ cm ⁻² .
including
each said one or more absorbent layers having a thickness measured in a first direction and an absorbent layer surface oriented parallel to a first plane and perpendicular to said first direction;
the die having a device cavity region with an optical window;
The device cavity region includes at least two opposing reflective members configured to internally reflect electromagnetic waves incident through the optical window to pass through the one or more absorbing layers at least twice. optical device comprising:
Embodiment 33
33. The optical device of embodiment 32, wherein the at least two opposing reflective members are further configured to internally reflect emitted light emitted from the one or more absorbing layers.
Embodiment 34
33. The optical device of embodiment 32, wherein the area of the optical window is less than 40% of the surface area of the absorbing layer surface.
Embodiment 35
33. The optical device of embodiment 32, wherein the device cavity region is configured to propagate light in directions within 20 degrees of the first plane.
Embodiment 36
33. The optical device of embodiment 32, wherein the device cavity region is configured to propagate light in directions between 20 degrees and 80 degrees from the first plane.
Embodiment 37
33. The optical device of embodiment 32, wherein the device cavity region is configured to propagate light in directions within 10 degrees of normal to the first plane.
Embodiment 38
33. The optic of embodiment 32, wherein the crystal orientation of each of the one or more absorbing layers and the first and second non-absorbing layers is within 5 degrees of (0001) or (000-1). device.
Embodiment 39
Embodiment 32, wherein the crystallographic orientation of each of the one or more absorbing layers and the first and second non-absorbing layers is within 5 degrees of one of {10-10} or {11-20}.Embodiment 32 The optical device according to .
Embodiment 40
The crystal orientations of each of the one or more absorbing layers and the first and second non-absorbing layers are {11-2±2}, {60-6±1}, {50-5±1}. , {40-4±1}, {30-3±1}, {50-5±2}, {70-7±3}, {20-2±1}, {30-3±2}, { 40-4±3}, {50-5±4}, {10-1±1}, {10-1±2}, {10-1±3}, {21-3±1}, or { 30−3±4} within 5 degrees of one.
Embodiment 41
33. The optical device of embodiment 32, wherein the one or more absorbing layers and the first and second non-absorbing layers each have a dislocation density of less than about ¹⁰⁸ cm ^-2 .
Embodiment 42
a substrate comprising a gallium-containing nitride,
further includes
The substrate, as quantified by calibrated secondary ion mass spectrometry (SIMS),
each of O, H, and C between about 1×10 16 ^cm −3 ^and 1×10 ¹⁹ cm ⁻³ , between about 1×10 ¹⁶ cm ⁻³ and 2×10 ¹⁹ cm ⁻³ , and an impurity concentration that is less than 1×10 ¹⁷ cm ⁻³ ;
and an impurity concentration of at least one of F, Cl, Na, and K that is between about 1×10 ¹⁵ cm ⁻³ and 1×10 ¹⁹ cm ⁻³ . .
Embodiment 43
substrate,
further includes
33. The optical device of embodiment 32, wherein the substrate includes a patterned array of features at an interface between the substrate and at least one of the first and second non-absorbing layers.
Embodiment 44
the features of the patterned array have a pitch of between about 0.2 micrometers and about 10 micrometers, the features have a height of between about 0.1 micrometers and about 10 micrometers, and , having a width of between 0.1 micrometers and about 5 micrometers.
Embodiment 45
a substrate;
an n-side reflective electrical connection;
p-side reflected electrical connection and
further comprising
The first non-absorbing layer is laminated on a first side of the substrate and the n-side reflective electrical connection is on a second side of the substrate opposite the first side of the substrate. 33. The optical device of embodiment 32, wherein the p-side reflective electrical connection is in electrical connection with the second non-absorbing layer.
Embodiment 46
a p-side reflective electrical connection comprising a discontinuous p-electrode and a reflective metal layer;
33. The optical device of embodiment 32, further comprising:
Embodiment 47
an n-side reflective electrical connection;
p-side reflected electrical connection and
further comprising
At least one of the n-side reflective electrical connection and the p-side reflective electrical connection includes TiO ₂ , Ta ₂ O ₅ , ZrO ₂ , SiO ₂ , SiO x , SiN _{x ,} Si ₃ N ₄ , SiO _x N _y , _47. The optical device of embodiment ₄₆ , comprising a dielectric layer comprising at least one of _Al2O3 or MgF2 .
Embodiment 48
an n-side reflective electrical connection;
p-side reflected electrical connection and
further comprising
at least one via penetrates the second non-absorbing layer and the one or more absorbing layers;
the n-side reflective electrical connection is in direct electrical contact with the first non-absorbing layer or a semi-transparent current spreading layer disposed on the second non-absorbing layer;
33. According to embodiment 32, wherein the p-side reflective electrical connection is in electrical connection with the second non-absorbing layer or the semi-transparent current spreading layer disposed on the second non-absorbing layer. optical device.
Embodiment 49
a light transmitting member;
an n-side reflective electrical connection;
p-side reflected electrical connection and
further comprising
The n-side electrical connection is formed by connecting a second surface of the light-transmitting member opposite to the first surface of the light-transmitting member and one of the first non-absorbing layer or the second non-absorbing layer. electrically connected to a semi-transparent current spreading layer disposed on an absorbing layer, the p-side reflective electrical connection being the second non-absorbing layer or semi-transparent disposed on the second non-absorbing layer 33. The optical device of embodiment 32, wherein at least one of the n-side and p-side reflective electrical connections are in electrical connection with a current spreading layer and are disposed transversely to the light transmissive member.
Embodiment 50
50. The embodiment of embodiment 49, wherein said at least one of said n-side and p-side reflective electrical connections disposed transversely to said light transmissive member are in electrical connection with said first non-absorbing layer. optical device.
Embodiment 51
an n-side reflective electrical connection;
p-side reflected electrical connection and
further comprising
at least one via penetrates the first non-absorbing layer and the one or more absorbing layers;
the n-side reflective electrical connection is in direct electrical contact with the first non-absorbing layer or a semi-transparent current spreading layer disposed on the second non-absorbing layer;
33. The embodiment of embodiment 32, wherein the p-side reflective electrical connection is in electrical connection with the second non-absorbing layer or a translucent current spreading layer disposed on the second non-absorbing layer. optical device.
Embodiment 52
The at least two opposing reflective members include an n-side reflective electrical connection and a p-side reflective electrical connection, wherein the n-side reflective electrical connection and the p-side reflective electrical connection are optically coupled within the device cavity region. 33. The optical device of embodiment 32, wherein the optical device is configured to change the direction of propagation of by more than about 30 degrees.
Embodiment 53
33. The optical device of embodiment 32, wherein the absorbing layer has a bandgap corresponding to wavelengths between about 400 nanometers and about 550 nanometers.
Embodiment 54
at least one absorber edge passivation in contact with at least one edge of the die;
33. The optical device of embodiment 32, further comprising:
Embodiment 55
_The edge passivation _{is AlNx} , _Al2O3 , TiO2 _, Ta2O5 , ZrO2 _{, SiO2} , SiOx , SiNx _{, Si3N4 , SiOxNy} , _{or SiuAl _} _ _ _{_} _ _{55. The} optical device of embodiment 54, comprising at least one of vOxNy _.
Embodiment 56
In an optical device,
A die comprising an optical window and at least two absorbing layers disposed between n-type first non-absorbing layers and second non-absorbing layers, the absorbing layers and the non-absorbing layers each being Al _x In _y Ga _1-x−y N, where 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ⁷ cm ⁻² ;
including
An optical device, wherein a separate n-connection is located on said first non-absorbing layer and a p-type connection is located on said second non-absorbing layer.
Embodiment 57
In optical assemblies,
at least one laser diode;
at least one optical fiber;
at least a first photodiode and
including
The laser diode includes at least one active layer comprising Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dislocation density of less than about 10 ⁷ cm ⁻² . have
The first photodiode includes at least one absorber layer comprising Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and less than about 10 ¹⁰ cm ⁻² having a dislocation density,
said laser diode configured to have an emission wavelength between about 400 nanometers and about 500 nanometers;
The optical assembly, wherein the first photodiode is configured to have an absorber bandgap wavelength between about 400 nanometers and about 550 nanometers.
Embodiment 58
The laser diode is configured to have an emission wavelength between 400 nm and 410 nm, and the photodiode has an absorber bandgap wavelength between 400 nm and 460 nm. is configured as
The laser diode is configured to have an emission wavelength between 440 nm and 460 nm, and the photodiode has an absorber bandgap wavelength between 440 nm and 500 nm. 58. The optical assembly of embodiment 57, which is configured to:
Embodiment 59
58. The optical assembly of embodiment 57, wherein at least one optical fiber has a branching structure.
Embodiment 60
at least one optical distribution device;
58. The optical assembly of embodiment 57, further comprising.
Embodiment 61
a control module configured to modulate the laser diode power with at least one controlled AC frequency and split the photodiode signal into a DC power component and an AC signal component at the at least one controlled frequency;
58. The optical assembly of embodiment 57, further comprising.
Embodiment 62
62. The optical assembly of embodiment 61, wherein the AC signal component is modulated at audio frequencies and the module is connected to headphones or audio speakers.
Embodiment 63
62. The optical assembly of embodiment 61, wherein amplitudes of the modulated AC components of the modulated laser diode power and the photodiode power are less than 10% of the corresponding DC components.
Embodiment 64
wherein said first photodiode configured to convert said DC power component to electrical power is further configured to detect said AC signal component at said at least one controlled frequency; 62. The optical assembly of aspect 61.
Embodiment 65
a separate signal photodetector device,
further includes
62. The optical assembly of embodiment 61, wherein the separate signal photodetector device is configured to detect the AC signal component at the at least one controlled frequency.
Embodiment 66
66. The optical assembly of embodiment 65, wherein the separate signal photodetector device is positioned between the end of the optical fiber and the first photodiode.
Embodiment 67
the separate signal photodetector device is positioned proximate to an optical coupling member, the optical coupling member being positioned between the end of the optical fiber and the first photodiode; 66. An optical assembly according to embodiment 65.
Embodiment 68
The at least one laser diode includes at least two laser diodes, the at least one photodiode includes at least two photodiodes, and the optical assembly directs signals in at least two different directions. 58. An optical assembly according to embodiment 57, configured to enable communication.
Embodiment 69
58. The optical assembly of embodiment 57, wherein the at least one photodiode is configured for both input and output of optical power.
Embodiment 70
at least one non-rigid or non-contact optical coupling to accommodate rotation of the photodiode with respect to the laser diode;
58. The optical assembly of embodiment 57, further comprising.
Embodiment 71
In an optical assembly,
at least one laser diode;
at least one optical fiber;
at least one photodiode and
including
The laser diode includes at least one active layer comprising Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dislocation density of less than about 10 ⁷ cm ⁻² . have
The photodiode includes at least one absorber layer comprising Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dislocation density of less than about 10 ¹⁰ cm ⁻² . have
said laser diode configured to have an emission wavelength between about 400 nanometers and about 500 nanometers;
the photodiode is configured to have an absorber bandgap wavelength between about 400 nanometers and about 550 nanometers;
An optical assembly that uses power from the photodiode to power Internet of Things sensors or actuators or personal electronic applications.
Embodiment 72
an illumination system comprising at least one of a phosphor, a heat sink, a reflective or transmissive optical member for forming a far-field distributed light, a sensor, and a control system;
72. The optical assembly of embodiment 71, further comprising.
Embodiment 73
73. The optical assembly according to embodiment 72, wherein the lighting system includes lighting fixtures.

Claims (73)

In optical assemblies,
A first die comprising one or more absorbent layers disposed between a first non-absorbent layer and a second non-absorbent layer, the one or more absorbent layers and the first and second The two non-absorbing layers each comprise Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ¹⁰ cm ⁻² . a first die;
a fixed part;
each said one or more absorbent layers having a thickness measured in a first direction and an absorbent layer surface oriented parallel to the first plane and perpendicular to the first direction;
The optical assembly has an optical cavity region with an optical window, the optical cavity region comprising:
a device cavity region comprising the one or more absorbing layers, the first non-absorbing layer, and the second non-absorbing layer;
at least two opposing reflective members configured to internally reflect electromagnetic waves incident through the optical window to pass through the device cavity region at least twice;
The optical assembly, wherein the fixture is configured to position a first end of an optical fiber a first distance from a surface of the optical window of the first die. 2. The optical assembly of Claim 1, wherein the first distance is between about 2 micrometers and about 10 millimeters. 3. The optical assembly of claim 2, wherein the first distance is constant and has a tolerance of between about 1 micrometer and about 1 millimeter. The optical fiber has a principal axis,
2. The optical assembly of claim 1, wherein an angle [alpha] between said principal axis of said optical fiber and said first plane is between zero and about 50 degrees. 2. The optical assembly of claim 1, wherein an angle [gamma] between the principal axis of the optical fiber and the direction normal to the surface of the optical window is between zero and about 60 degrees. 2. The optical assembly of claim 1, wherein an angle [beta] between the major axis of said optical fiber and the edge of said first die is between zero and about 60 degrees. 7. The optical assembly of claim 6, wherein said angle [beta] is between zero and approximately 20 degrees. 2. The optical assembly of claim 1, wherein an angle [gamma] between the principal axis of said optical fiber and a direction normal to said first plane is between about 0 and 60 degrees. a mirror configured to reflect light radiation from a light source onto the surface of the optical window;
The optical assembly of Claim 1, further comprising: a second die including an optical cavity region having an optical window;
further includes
The mirror reflects light radiation from the light source to the surface of the optical window of the first die and further reflects light radiation from the light source to the surface of the optical window of the second die. 10. An optical assembly according to claim 9, configured to: 2. The optical assembly of claim 1, wherein the optical cavity region comprises a first light transmissive member and a second light transmissive member optically connected to the first light transmissive member. an optical coupling member disposed between the first end of the optical fiber and the optical window and configured to diffuse the optical radiation in a direction parallel to the surface of the optical window;
The optical assembly of Claim 1, further comprising: an optical coupling member disposed between the first end of the optical fiber and the optical window and configured to diffuse the optical radiation in a direction parallel to the edge of the first die; ,
The optical assembly of Claim 1, further comprising: an integrating sphere configured to couple optical radiation received from the first end of the optical fiber into the device cavity region of the first die;
The optical assembly of Claim 1, further comprising: an optical coupling member disposed between the first end of the optical fiber and the optical window;
further includes
The optical window includes a reflective electrical connection having an aperture, and the optical coupling member is configured to diffuse the optical radiation in two orthogonal directions in the first plane. The optical assembly of claim 1. a fiber coupling lens disposed between the first end of the optical fiber and the optical coupling member;
16. The optical assembly of claim 15, further comprising. a fiber coupling lens between the first end of the optical fiber and the optical coupling member;
17. The optical assembly of claim 16, further comprising. The device cavity region further includes an n-side reflective electrical connection and a p-side reflective electrical connection, the optical window positioned in one of the n-side reflective electrical connection and the p-side reflective electrical connection. 2. The optical assembly of claim 1, which is a The optical window includes a surface configured to receive the electromagnetic wave and is positioned on an edge of the first die, the area of the surface of the optical window being equal to the first 2. The optical assembly of claim 1, which is between about 1% and about 20% of the area of the edge of the die. a fiber coupling lens positioned between the first end of the optical fiber and the optical window;
20. The optical assembly of Claim 19, further comprising. In optical assemblies,
A first die comprising one or more absorbent layers disposed between a first non-absorbent layer and a second non-absorbent layer, the one or more absorbent layers and the first and second The two non-absorbing layers each comprise Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ¹⁰ cm ⁻² . a first die;
an optical element and
each said one or more absorbent layers having a thickness measured in a first direction and an absorbent layer surface oriented parallel to the first plane and perpendicular to the first direction;
the first die having a device cavity region with an optical window;
The device cavity region includes at least two opposing reflective members configured to internally reflect electromagnetic waves incident through the optical window to pass through the one or more absorbing layers at least twice. includes
An optical assembly, wherein the optical element is configured to receive optical radiation from an optical fiber and transmit the received optical radiation to at least a portion of the optical window. 22. The optical assembly of claim 21, wherein said optical element comprises an optical waveguide or optical coupling member. 22. The optical assembly of Claim 21, wherein said optical fiber includes a major axis and a radiation output end located a first distance from a surface of said optical window of said first die. an optical fiber coupling lens positioned between the radiation output end of the optical fiber and the optical window;
22. The optical assembly of claim 21, further comprising. The optical fiber has a principal axis,
22. The optical assembly of claim 21, wherein an angle [alpha] between said principal axis of said optical fiber and said first plane is between zero and about 50 degrees. The optical fiber has a principal axis,
22. The optical assembly of claim 21, wherein an angle [beta] between the principal axis of the optical fiber and the surface of the optical window is between zero and approximately 60 degrees. The optical fiber has a principal axis,
22. The optical assembly of claim 21, wherein an angle [beta] between said major axis of said optical fiber and an edge of said first die is between zero and about 60 degrees. 28. The optical assembly of Claim 27, wherein said angle β is between zero and approximately 20 degrees. The optical fiber has a principal axis,
22. The optical assembly of claim 21, wherein an angle [gamma] between said principal axis of said optical fiber and a direction normal to said first plane is between about 0 and about 60 degrees. 22. The optical assembly of Claim 21, wherein said optical element is configured to diffuse said optical radiation in a direction parallel to an edge of said first die. 22. The optical assembly of claim 21, wherein said optical element is arranged to spread said optical radiation in two orthogonal directions in said first plane. In an optical device,
A die comprising one or more absorbent layers disposed between a first non-absorbent layer and a second non-absorbent layer, the one or more absorbent layers and the first and second non-absorbent layers. The absorber layers each comprise Al _x In _y Ga _1-x-y N, with 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ¹⁰ cm ⁻² . including
each said one or more absorbent layers having a thickness measured in a first direction and an absorbent layer surface oriented parallel to a first plane and perpendicular to said first direction;
the die having a device cavity region with an optical window;
The device cavity region includes at least two opposing reflective members configured to internally reflect electromagnetic waves incident through the optical window to pass through the one or more absorbing layers at least twice. optical device comprising: 33. The optical device of Claim 32, wherein the at least two opposing reflective members are further configured to internally reflect emitted light emitted from the one or more absorbing layers. 33. The optical device of claim 32, wherein the area of said optical window is less than 40% of the surface area of said absorbing layer surface. 33. The optical device of Claim 32, wherein the device cavity region is configured to propagate light in directions within 20 degrees of the first plane. 33. The optical device of Claim 32, wherein the device cavity region is configured to propagate light in directions between 20 degrees and 80 degrees from the first plane. 33. The optical device of Claim 32, wherein the device cavity region is configured to propagate light in directions within 10 degrees of normal to the first plane. 33. The optic of claim 32, wherein the crystallographic orientation of each of the one or more absorbing layers and the first and second non-absorbing layers is within 5 degrees of (0001) or (000-1). device. Claim 32, wherein the crystallographic orientation of each of the one or more absorbing layers and the first and second non-absorbing layers is within 5 degrees of one of {10-10} or {11-20}. The optical device according to . The crystal orientations of each of the one or more absorbing layers and the first and second non-absorbing layers are {11-2±2}, {60-6±1}, {50-5±1}. , {40-4±1}, {30-3±1}, {50-5±2}, {70-7±3}, {20-2±1}, {30-3±2}, { 40-4±3}, {50-5±4}, {10-1±1}, {10-1±2}, {10-1±3}, {21-3±1}, or { 30-3±4} within 5 degrees. 33. The optical device of Claim 32, wherein the one or more absorbing layers and the first and second non-absorbing layers each have a dislocation density of less than about ¹⁰⁸ cm ^-2 . a substrate comprising a gallium-containing nitride,
further includes
The substrate, as quantified by calibrated secondary ion mass spectrometry (SIMS),
each of O, H, and C between about 1×10 ¹⁶ cm ⁻³ and 1×10 ¹⁹ cm ⁻³ , between about 1×10 ¹⁶ cm ⁻³ and 2×10 ¹⁹ cm ⁻³ , and an impurity concentration that is less than 1×10 ¹⁷ cm ⁻³ ;
and an impurity concentration of at least one of F, Cl, Na, and K that is between about 1×10 ¹⁵ cm ⁻³ and 1×10 ¹⁹ cm ⁻³ . . substrate,
further includes
33. The optical device of Claim 32, wherein the substrate includes a patterned array of features at an interface between the substrate and at least one of the first and second non-absorbing layers. the features of the patterned array have a pitch of between about 0.2 micrometers and about 10 micrometers, the features have a height of between about 0.1 micrometers and about 10 micrometers, and , having a width of between 0.1 micrometer and about 5 micrometers. a substrate;
an n-side reflective electrical connection;
a p-side reflective electrical connection;
The first non-absorbing layer is laminated on a first side of the substrate and the n-side reflective electrical connection is on a second side of the substrate opposite the first side of the substrate. 33. The optical device of claim 32, wherein the p-side reflective electrical connection is in electrical connection with the second non-absorbing layer. a p-side reflective electrical connection comprising a discontinuous p-electrode and a reflective metal layer;
33. The optical device of Claim 32, further comprising. an n-side reflective electrical connection;
a p-side reflective electrical connection;
At least one of the n-side reflective electrical connection and the p-side reflective electrical connection includes TiO ₂ , Ta ₂ O ₅ , ZrO _{2 , SiO 2 ,} SiO x , SiN _{x ,} Si ₃ N ₄ , SiO _x N _y , 47. The optical device of Claim ₄₆ , comprising a dielectric layer comprising at least one of _Al2O3 or _MgF2 . an n-side reflective electrical connection;
a p-side reflective electrical connection;
at least one via penetrates the second non-absorbing layer and the one or more absorbing layers;
the n-side reflective electrical connection is in direct electrical contact with the first non-absorbing layer or a semi-transparent current spreading layer disposed on the second non-absorbing layer;
33. The p-side reflective electrical connection of claim 32, wherein the p-side reflective electrical connection is electrically connected to the second non-absorbing layer or the semi-transparent current spreading layer disposed on the second non-absorbing layer. optical device. a light transmitting member;
an n-side reflective electrical connection;
a p-side reflective electrical connection;
The n-side electrical connection is formed by connecting a second surface of the light-transmitting member opposite to the first surface of the light-transmitting member and one of the first non-absorbing layer or the second non-absorbing layer. electrically connected to a semi-transparent current spreading layer disposed on an absorbing layer, the p-side reflective electrical connection being the second non-absorbing layer or semi-transparent disposed on the second non-absorbing layer 33. The optical device of claim 32, wherein at least one of the n-side and p-side reflective electrical connections are in electrical connection with a current spreading layer and are disposed transversely to the light transmissive member. 50. The claim of claim 49, wherein said at least one of said n-side and p-side reflective electrical connections disposed transversely to said light transmissive member are in electrical connection with said first non-absorbing layer. optical device. an n-side reflective electrical connection;
a p-side reflective electrical connection;
at least one via penetrates the first non-absorbing layer and the one or more absorbing layers;
the n-side reflective electrical connection is in direct electrical contact with the first non-absorbing layer or a semi-transparent current spreading layer disposed on the second non-absorbing layer;
33. The p-side reflective electrical connection of claim 32, wherein the p-side reflective electrical connection is in electrical connection with the second non-absorbing layer or a translucent current spreading layer disposed on the second non-absorbing layer. optical device. The at least two opposing reflective members include an n-side reflective electrical connection and a p-side reflective electrical connection, wherein the n-side reflective electrical connection and the p-side reflective electrical connection are coupled to the optical cavity within the optical cavity region. 33. The optical device of claim 32, wherein the optical device is configured to change the direction of propagation of by more than about 30 degrees. 33. The optical device of Claim 32, wherein the absorbing layer has a bandgap corresponding to wavelengths between about 400 nanometers and about 550 nanometers. at least one absorber edge passivation in contact with at least one edge of the die;
33. The optical device of Claim 32, further comprising. The edge passivation is _{AlNx , Al2O3} , _{TiO2 , Ta2O5} , _{ZrO2 , SiO2} , _SiOx , _SiNx , _{Si3N4 , SiOxNy} , or _{SiuAl 55.} The optical device _of claim 54, comprising at least one of _vOxNy . In an optical device,
A die comprising an optical window and at least two absorbing layers disposed between n-type first non-absorbing layers and second non-absorbing layers, the absorbing layers and the non-absorbing layers each being Al _x In _y Ga _1-x-y N, wherein 0≦x, y, x+y≦1 and having a dislocation density of less than about 10 ⁷ cm ⁻² ;
An optical device, wherein a separate n-connection is located on said first non-absorbing layer and a p-type connection is located on said second non-absorbing layer. In optical assemblies,
at least one laser diode;
at least one optical fiber;
at least a first photodiode;
The laser diode includes at least one active layer comprising Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dislocation density of less than about 10 ⁷ cm ⁻² . have
The first photodiode includes at least one absorber layer comprising Al _x In _y Ga _1-x-y N, where 0≦x, y, x+y≦1 and less than about 10 ¹⁰ cm ⁻² having a dislocation density,
said laser diode configured to have an emission wavelength between about 400 nanometers and about 500 nanometers;
The optical assembly, wherein the first photodiode is configured to have an absorber bandgap wavelength between about 400 nanometers and about 550 nanometers. The laser diode is configured to have an emission wavelength between 400 nm and 410 nm, and the photodiode has an absorber bandgap wavelength between 400 nm and 460 nm. is configured as
The laser diode is configured to have an emission wavelength between 440 nm and 460 nm, and the photodiode has an absorber bandgap wavelength between 440 nm and 500 nm. 58. The optical assembly of Claim 57, configured to: 58. The optical assembly of Claim 57, wherein at least one optical fiber has a branching structure. at least one optical distribution device;
58. The optical assembly of Claim 57, further comprising. a control module configured to modulate the laser diode power with at least one controlled AC frequency and split the photodiode signal into a DC power component and an AC signal component at the at least one controlled frequency;
58. The optical assembly of Claim 57, further comprising. 62. The optical assembly of Claim 61, wherein the AC signal component is modulated at audio frequencies and the module is connected to headphones or audio speakers. 62. The optical assembly of Claim 61, wherein amplitudes of said modulated AC components of said modulated laser diode power and said photodiode power are less than 10% of said corresponding DC components. The first photodiode configured to convert the DC power component to electrical power is further configured to detect the AC signal component at the at least one controlled frequency. 62. Optical assembly according to Clause 61. a separate signal photodetector device,
further includes
62. The optical assembly of Claim 61, wherein said separate signal photodetector device is configured to detect said AC signal component at said at least one controlled frequency. 66. The optical assembly of Claim 65, wherein the separate signal photodetector device is positioned between the end of the optical fiber and the first photodiode. the separate signal photodetector device is positioned proximate to an optical coupling member, the optical coupling member being positioned between the end of the optical fiber and the first photodiode; 66. An optical assembly according to claim 65. The at least one laser diode includes at least two laser diodes, the at least one photodiode includes at least two photodiodes, and the optical assembly directs signals in at least two different directions. 58. The optical assembly of Claim 57 configured to enable communication. 58. The optical assembly of Claim 57, wherein said at least one photodiode is configured for both input and output of optical power. at least one non-rigid or non-contact optical coupling to accommodate rotation of the photodiode with respect to the laser diode;
58. The optical assembly of Claim 57, further comprising. In optical assemblies,
at least one laser diode;
at least one optical fiber;
at least one photodiode;
The laser diode includes at least one active layer comprising Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dislocation density of less than about 10 ⁷ cm ⁻² . have
The photodiode includes at least one absorber layer comprising Al _x In _y Ga _1-x-y N with 0≦x, y, x+y≦1 and a dislocation density of less than about 10 ¹⁰ cm ⁻² . have
said laser diode configured to have an emission wavelength between about 400 nanometers and about 500 nanometers;
the photodiode is configured to have an absorber bandgap wavelength between about 400 nanometers and about 550 nanometers;
An optical assembly that uses power from the photodiode to power Internet of Things sensors or actuators or personal electronic applications. an illumination system comprising at least one of a phosphor, a heat sink, a reflective or transmissive optical member for forming a far-field distributed light, a sensor, and a control system;
72. The optical assembly of Claim 71, further comprising. 73. The optical assembly of Claim 72, wherein said illumination system includes a lighting fixture.

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