CN117977376A - Surface-emitting laser device and method for manufacturing the same - Google Patents

Abstract

The application discloses a surface-emitting laser device and a manufacturing method thereof. The surface-emitting laser device comprises a first reflector layer, an active light emitting layer, a second reflector layer and a current limiting structure. The active light emitting layer is located between the first mirror layer and the second mirror layer to generate a laser beam. The current confinement structure has a PN junction or a PIN junction.

Description

Surface-emitting laser device and method for manufacturing the same

Technical Field

The present application relates to a surface-emitting laser device and a method for manufacturing the same, and more particularly, to a vertical cavity surface-emitting laser device and a method for manufacturing the same.

Background

The conventional vertical co-cavity surface emitting laser at least comprises a P-type electrode, an N-type electrode, an active layer for generating photons, and an upper Bragg reflector (Distributed Bragg Reflector, DBR) and a lower Bragg reflector which are respectively positioned at two sides of the active layer. The laser beam emitted from the element surface (i.e., perpendicular to the active layer direction) is generated by applying a bias voltage to the P-type electrode and the N-type electrode to inject a current into the active layer to excite photons, and forming a vertical resonant cavity using the upper and lower bragg reflectors (Distributed Bragg Reflector, DBR).

In conventional vertical co-cavity surface emitting lasers, ion implantation or wet oxidation processes are typically used to form oxide layers or ion implantation regions with high resistance in the upper Bragg reflector to limit the current passing region. However, the ion implantation or thermal oxidation process is used to form the oxide layer or ion implantation region with limited current, which is costly and the aperture size is not easy to control.

In addition, the lattice mismatch degree and the thermal expansion coefficient between the oxide layer and the semiconductor material forming the upper Bragg reflector are large, so that the vertical co-cavity surface-emitting laser is easy to break due to internal stress after annealing, and the process yield is reduced. Stress in the device also reduces the lifetime of the device, affects the light extraction characteristics, and reduces reliability. On the other hand, the conventional vertical co-cavity surface emitting laser is easily damaged inside due to the impact of electrostatic discharge (electrostatic discharge, ESD) or surge (Surge).

Disclosure of Invention

The application aims to solve the technical problem of providing a surface-emitting laser device and a manufacturing method thereof aiming at the defects of the prior art so as to reduce the internal stress of the surface-emitting laser device and improve the antistatic capability of the surface-emitting laser device.

In order to solve the above-mentioned problems, one of the technical solutions adopted by the present application is to provide an area-emission laser device, which includes a first mirror layer, an active light emitting layer, a second mirror layer, and a current confinement structure. The active light emitting layer is located between the first reflector layer and the second reflector layer to generate a laser beam. The current confinement structure has a PN junction or a PIN junction.

In order to solve the above-mentioned problems, another aspect of the present application is to provide an area-emission laser device, which includes a first mirror layer, an active light emitting layer, a second mirror layer, and a current confinement structure. The active light emitting layer is located between the first reflector layer and the second reflector layer to generate a laser beam. The current confinement structure has a zener diode (zener diode).

In order to solve the above-mentioned problems, another aspect of the present application provides a method for manufacturing a surface-emitting laser device, including: forming a first mirror layer; forming an active light emitting layer on the first reflector layer; forming a current limiting structure, wherein the current limiting structure defines a limiting hole and is provided with a PN junction or a PIN junction; and forming a second mirror layer.

The surface-emitting laser device and the manufacturing method thereof have the advantages that the technical scheme that the current limiting structure is provided with a PN junction or a PIN junction or the current limiting structure is provided with a zener diode is adopted, so that the surface-emitting laser device has better reliability and the antistatic capability of the surface-emitting laser device is improved.

For a further understanding of the nature and the technical aspects of the present application, reference should be made to the following detailed description of the application and to the accompanying drawings, which are provided for purposes of reference only and are not intended to limit the application.

Drawings

Fig. 1 is a schematic cross-sectional view of an area-emission laser device according to a first embodiment of the present application.

Fig. 2 is an enlarged schematic view of section II of fig. 1.

Fig. 3 is an enlarged partial view of an area-emission laser device according to another embodiment of the present application.

Fig. 4 is a schematic cross-sectional view of an area-emission laser device according to a second embodiment of the present application.

Fig. 5 is a schematic cross-sectional view of an area-emission laser device according to a third embodiment of the present application.

Fig. 6 is a schematic cross-sectional view of an area-emission laser device according to a fourth embodiment of the present application.

Fig. 7 is an enlarged schematic view of the VII portion of fig. 6.

Fig. 8 is a partially enlarged schematic view of an area-emission laser device according to another embodiment of the present application.

Fig. 9 is a schematic cross-sectional view of a surface-emitting laser device according to a fifth embodiment of the present application.

Fig. 10 is a flowchart of a method of manufacturing a surface-emitting laser device according to an embodiment of the present application.

Fig. 11 is a schematic diagram of a surface-emitting laser device according to an embodiment of the application in step S10.

Fig. 12 is a schematic diagram of a surface-emitting laser device according to an embodiment of the application in step S20.

Fig. 13 and 14 are schematic diagrams of an area-emission laser device according to an embodiment of the application in step S30.

Fig. 15 is a schematic diagram of a surface-emitting laser device according to an embodiment of the application in step S40.

Fig. 16 is a schematic diagram of a surface-emitting laser device according to an embodiment of the application in step S50.

Fig. 17 is a schematic diagram of an area-emission laser device according to another embodiment of the application in step S40.

Fig. 18 is a schematic diagram of an area-emission laser device according to another embodiment of the application in step S50.

Detailed Description

The following description is given of specific embodiments of the present application with respect to an "surface-emitting laser device and a method for manufacturing the same", and those skilled in the art will appreciate the advantages and effects of the present application from the disclosure of the present application. The application is capable of other and different embodiments and its several details are capable of modification and variation in various respects, all from the point of view and application, all without departing from the spirit of the present application. The drawings of the present application are merely schematic illustrations, and are not intended to be drawn to actual dimensions. The following embodiments will further illustrate the related art content of the present application in detail, but the disclosure is not intended to limit the scope of the present application. In addition, the term "or" as used herein shall include any one or combination of more of the associated listed items as the case may be.

First embodiment referring to fig. 1 and 2, an embodiment of the present application provides an area-emission laser device Z1. In the embodiment of the present application, the surface-emitting laser device Z1 is a vertical cavity surface-emitting laser device. The surface-emitting laser device Z1 includes a first mirror layer 11, an active light emitting layer 12, a second mirror layer 13, and a current confinement structure 14. In detail, in the present embodiment, the surface-emitting laser device Z1 further includes a substrate 10. The first mirror layer 11, the active light emitting layer 12, the second mirror layer 13 and the current confinement structure 14 are all disposed on the substrate 10, and the active light emitting layer 12 is disposed between the first mirror layer 11 and the second mirror layer 13.

The substrate 10 may be an insulating substrate or a semiconductor substrate. The insulating substrate is, for example, sapphire, and the semiconductor substrate is, for example, silicon, germanium, silicon carbide or a III-V semiconductor. The group III-V semiconductor is, for example, gallium arsenide (GaAs), arsenic phosphide (InP), aluminum Nitride (AIN), indium Nitride (InN), or gallium Nitride (GalliumNitride, gaN). In addition, the substrate 10 has an epitaxial surface 10a and a bottom surface 10b opposite to the epitaxial surface 10 a.

The first mirror layer 11, the active light emitting layer 12 and the second mirror layer 13 are sequentially disposed on the epitaxial surface 10a of the substrate 10. In the present embodiment, the first mirror layer 11, the active light emitting layer 12, and the second mirror layer 13 have the same cross-sectional width as the active light emitting layer 12.

The first mirror layer 11 and the second mirror layer 13 may be distributed bragg reflectors (Distributed Bragg Reflector, DBR) formed by alternately stacking two kinds of thin films having different refractive indexes so as to have a predetermined wavelength reflection resonance. In the present embodiment, the materials constituting the first mirror layer 11 and the second mirror layer 13 may be doped III-V compound semiconductors, and the first mirror layer 11 and the second mirror layer 13 have different conductivity types, respectively.

The active light emitting layer 12 is formed on the first mirror layer 11 to generate a laser beam L. In detail, the active light emitting layer 12 is located between the first mirror layer 11 and the second mirror layer 13, and is used for being excited by electric energy to generate an initial light beam. The initial beam generated by the active light emitting layer 12 is gain-amplified by reflection resonance back and forth between the first mirror layer 11 and the second mirror layer 13, and finally exits from the second mirror layer 13 to generate a laser beam L.

The active light emitting layer 12 includes multiple layers for forming multiple quantum wells, such as multiple layers stacked alternately with each other and without doped well layers and barrier layers. The materials of the well layer and the barrier layer are determined according to the wavelength of the laser beam L to be generated. For example, when the laser beam L to be generated is red light, the well layer and the barrier layer may be a gallium arsenide layer and an aluminum gallium arsenide (AlxGa (1-x) As) layer, respectively. When the laser beam L to be generated is blue light, the barrier layer and the well layer may be a gallium nitride (GaN) layer and an indium gallium nitride (InGaN) layer, respectively. However, the application is not limited to the foregoing examples.

Referring to fig. 1 and 2, the surface-emitting laser device Z1 further includes a current confinement structure 14, and the current confinement structure 14 is located above or below the active light emitting layer 12. The current confinement structure 14 has a confinement aperture 14H to define a current path. It should be noted that, as long as the current confinement structure 14 can be used to define the area through which the current passes, the location of the current confinement structure 14 is not limited in the present application. In this embodiment, the current confinement structure 14 is disposed in the second mirror layer 13 and connected to the active light emitting layer 12. In detail, as shown in fig. 2, in this embodiment, a portion of the second mirror layer 13 fills the limiting hole 14H and is connected to the active light emitting layer 12. Since the second mirror layer 13 is a doped semiconductor material having high conductivity, the portion of the second mirror layer 13 filled into the confinement holes 14H allows current to pass.

As shown in fig. 2, in the present embodiment, the current confinement structure 14 has at least one PN junction SA. In detail, the current confinement structure 14 includes a first conductive type doped layer 141 and a second conductive type doped layer 142, and a PN junction SA is formed between the first conductive type doped layer 141 and the second conductive type doped layer 142. In detail, the first conductive type doped layer 141 and the first mirror layer 11 have opposite conductive types, and the second conductive type doped layer 142 and the second mirror layer 13 also have opposite conductive types. For example, when the first mirror layer 11 is N-type, the second mirror layer 13 and the first conductive type doped layer 141 are P-type, and the second conductive type doped layer 142 is N-type. When the first mirror layer 11 is P-type, the second mirror layer 13 and the first conductive doped layer 141 are both N-type, and the second conductive doped layer 142 is P-type.

As shown in fig. 2, the current confinement structure 14 is disposed with the first conductive type doped layer 141 facing the first mirror layer 11. Since the second mirror layer 13 and the second conductive type doped layer 142 have opposite conductive types, the second mirror layer 13 and the second conductive type doped layer 142 form another PN junction SB in the surface-emitting laser device Z1. Accordingly, the current confinement structure 14 of the present embodiment has a zener diode (zener diode) formed by the first conductive type doped layer 141 and the second conductive type doped layer 142.

The material constituting the current confinement structure 14 may be a semiconductor material that does not absorb the laser beam. In other words, the material constituting the current confinement structure 14 may allow the laser beam L to penetrate. Assuming that the wavelength of the laser beam L is λ (in nanometers) and the energy gap width of the semiconductor material constituting the current confinement structure 14 is Eg, the energy gap width Eg and the wavelength λ of the laser beam L may satisfy the following relationship: eg > (1240/lambda). For example, when the wavelength λ of the laser beam L is 850nm, the energy gap width Eg of the semiconductor material constituting the current confinement structure 14 is greater than 1.46eV. Thus, the current confinement structure 14 can be prevented from absorbing the laser beam L, and the light emission efficiency of the surface-emitting laser device Z1 can be reduced. In one embodiment, the energy gap width (energybandgap) of the semiconductor material constituting the current confinement structure 14 is greater than the energy gap width of the semiconductor material constituting the active light emitting layer 12 (well layer).

In addition, in the present embodiment, the lattice constant of the material constituting the current confinement structure 14 and the lattice constant of the material constituting the active light emitting layer 12 may be matched to each other to reduce interface defects. In a preferred embodiment, the lattice mismatch (LATTICE MISMATCH) between the material comprising the current confinement structure 14 and the material comprising the active light-emitting layer 12 is less than or equal to 0.1%. In addition, since the current confinement structure 14 of the present embodiment is located in the second mirror layer 13, the lattice mismatch degree (LATTICE MISMATCH) between the material constituting the current confinement structure 14 and the material constituting the second mirror layer 13 is less than or equal to 0.1%.

Compared with the existing oxide layer, the lattice mismatch degree between the current confinement structure 14 and the active light emitting layer 12 and between the current confinement structure and the second mirror layer 13 is smaller, so that the internal stress of the surface-emitting laser device Z1 can be reduced, and the reliability of the surface-emitting laser device Z1 can be increased. In this embodiment, the total thickness of the current confinement structure 14 ranges from 10nm to 1000nm. Since the current confinement structure 14, the active light emitting layer 12, and the second mirror layer 13 are all made of semiconductor materials, the difference in thermal expansion coefficients is small. Thus, the surface-emitting laser device Z1 can be prevented from being broken due to the difference of thermal expansion coefficients after annealing treatment, and the process yield can be improved.

Referring to fig. 1, the surface-emitting laser device Z1 according to the embodiment of the application further includes a first electrode layer 15 and a second electrode layer 16. The first electrode layer 15 is electrically connected to the first mirror layer 11, and the second electrode layer 16 is electrically connected to the second mirror layer 13. In the embodiment of fig. 1, the first electrode layer 15 and the second electrode layer 16 are respectively located on different sides of the substrate 10, however, in other embodiments, the first electrode layer 15 and the second electrode layer 16 may both be located on the same side of the substrate 10.

Further, in the present embodiment, the first electrode layer 15 is disposed on the bottom surface 10b of the substrate 10. The second electrode layer 16 is disposed on the second mirror layer 13 and electrically connected to the second mirror layer 13. A current path is defined between the first electrode layer 15 and the second electrode layer 16 through the active light emitting layer 12. The first electrode layer 15 and the second electrode layer 16 may be a single metal layer, an alloy layer, or a laminate composed of different metal materials.

In the embodiment of fig. 1, the second electrode layer 16 has an opening 16H for defining a light emitting area A1, and the opening 16H corresponds to the confining hole 14H of the current confinement structure 14, so that the laser beam L generated by the active light emitting layer 12 can be emitted from the opening 16H. In one embodiment, the second electrode layer 16 has an annular portion, but the present application is not limited to the top view pattern of the second electrode layer 16. The material of the second electrode layer 12 may be gold, tungsten, germanium, palladium, titanium or any combination thereof.

In addition, the surface-emitting laser device Z1 of the present embodiment further includes a current spreading layer 17 and a protective layer 18. The current spreading layer 17 is located on the second reflector layer 13 and is electrically connected to the second electrode layer 16. In an embodiment, the material constituting the current spreading layer 17 is a conductive material, so that the current injected into the active light emitting layer 12 by the second mirror layer 13 is uniformly distributed. In addition, the material constituting the current spreading layer 17 is a material that is penetrable by the laser beam L to avoid excessively sacrificing the light emission efficiency of the surface-emitting laser device Z1. For example, when the wavelength of the laser beam L is 850nm, the material constituting the current spreading layer 17 may be a doped semiconductor material, such as heavily doped gallium arsenide, but the application is not limited thereto.

The protection layer 18 covers the current spreading layer 17 and the light emitting area A1 to prevent moisture from entering the surface-emitting laser device Z1, thereby affecting the light emitting characteristics or lifetime of the surface-emitting laser device Z1. In one embodiment, the protection layer 18 may be made of a material resistant to moisture, such as: silicon nitride, aluminum oxide, or combinations thereof, the application is not limited. In the present embodiment, the second electrode layer 16 is disposed on the protection layer 18, and is connected to the second mirror layer 13 through the protection layer 18 and the current spreading layer 17, but the application is not limited thereto. In another embodiment, the current spreading layer 17 may also be omitted.

It should be noted that at least a portion of the zener diode of the current confinement structure 14 is located on the current path defined by the first electrode layer 15 and the second electrode layer 16 to block the current from passing. Accordingly, when the surface-emitting laser device Z1 is biased through the first electrode layer 15 and the second electrode layer 16, the zener diode of the current confinement structure 14 is reverse biased, but is not broken down. Accordingly, the zener diode is not turned on, so that the current is driven to bypass the current confinement structure 14 and pass through only the confinement holes 14H, thereby increasing the current density of the current injected into the active light emitting layer 12.

However, when an electrostatic discharge is generated, the zener diode of the current confinement structure 14 is turned on regardless of whether the electrostatic current is a positive current or a negative current. Since the resistance of the zener diode when turned on will be much lower than the resistance of the second mirror layer 13 located within the confinement holes 14H, most of the electrostatic current will pass through the current confinement structure 14 and not through the confinement holes 14H. The current confinement structure 14 has a larger top-view area than the confinement holes 14H. When the zener diode of the current confinement structure 14 is turned on, the electrostatic current flowing through the active light emitting layer 12 can be dispersed, so as to reduce the current density, and avoid damaging the active light emitting layer 12. Accordingly, the current confinement structure 14 can provide electrostatic discharge protection to the surface emitting laser device Z1.

That is, in the surface-emitting laser device Z1 according to the embodiment of the present application, by providing the current confinement structure 14 with the zener diode, not only the current path can be defined, but also the electrostatic discharge protection can be provided to the surface-emitting laser device Z1, and the reliability can be improved.

Referring to fig. 3, a schematic enlarged view of a portion of an surface-emitting laser device according to another embodiment of the application is shown. In this embodiment, the current confinement structure 14 has a PIN junction, and the same effect can be achieved. In detail, the current confinement structure 14 of the present embodiment may include a first conductive type doped layer 141, a second conductive type doped layer 142, and an intrinsic semiconductor layer 143.

The intrinsic semiconductor layer 143 is located between the first conductive type doped layer 141 and the second conductive type doped layer 142. The intrinsic semiconductor layer 143 is an undoped semiconductor layer, and the semiconductor material constituting the intrinsic semiconductor layer 143 may be the same as the semiconductor material constituting the first conductive type doped layer 141 (or the second conductive type doped layer 142), but the present application is not limited thereto.

Thus, when the surface emitting laser device Z1 is biased, the second conductive doped layer 142 and the first conductive doped layer 141 of the current confinement structure 14 are equivalent to the reverse bias applied with less than the breakdown voltage, so that the current confinement structure 14 is in a non-conductive state. Thus, current is only allowed to pass through the confining aperture 14H of the current confining structure 14.

When an electrostatic discharge is generated such that the reverse bias voltage applied to the current confinement structure 14 is greater than the breakdown voltage, the current confinement structure 14 may be in a conductive state, so that most of the electrostatic current passes through the current confinement structure 14. By disposing the intrinsic semiconductor layer 143 between the first conductive type doped layer 141 and the second conductive type doped layer 142, the electrostatic discharge protection capability of the current confinement structure 14 on the surface emitting laser device Z1 can be further improved.

Referring to fig. 4, fig. 4 is a schematic cross-sectional view of a surface-emitting laser device according to a second embodiment of the present application. The elements of the surface-emitting laser device Z2 in this embodiment that are the same as those of the surface-emitting laser device Z1 in the first embodiment have the same reference numerals, and the same parts will not be described again.

In the surface-emitting laser device Z2 of the present embodiment, the current confinement structure 14 is disposed in the second mirror layer 13, but is not connected to the active light emitting layer 12. It should be noted that, in the present embodiment, the current confinement structure 14 may be located closer to the active light emitting layer 12 and further from the second electrode layer 16. Thus, the current injected into the active light emitting layer 12 through the limiting hole 14H can be concentrated, so that the surface-emitting laser device Z2 has high light emitting efficiency. The current confinement structure 14 may be the structure shown in fig. 2 or 3. In the present embodiment, the current confinement structure 14 is disposed with the first conductive type doped layer 141 toward the first mirror layer 11 and connected to the lower portion of the second mirror layer 13. In addition, the second conductive type doped layer 142 of the current confinement structure 14 is connected to the upper portion of the second mirror layer 13, and a PN junction SB is still formed between the second conductive type doped layer 142 and the second mirror layer 13.

Thus, when the surface emitting laser device Z1 is biased, the second conductive doped layer 142 and the first conductive doped layer 141 of the current confinement structure 14 are reversely biased with less than the breakdown voltage, so that the current confinement structure 14 is in a non-conductive state. Thus, current is only allowed to pass through the confining aperture 14H of the current confining structure 14. Accordingly, the present application is not limited to the location of the current confinement structure 14 within the second mirror layer 13, so long as the current confinement structure 14 can confine the current and provide electrostatic discharge protection to the surface emitting laser device Z2.

Third embodiment

Referring to fig. 5, fig. 5 is a schematic cross-sectional view of a surface-emitting laser device according to a third embodiment of the application. The elements of the surface-emitting laser device Z3 in this embodiment that are the same as those of the surface-emitting laser device Z1 in the first embodiment have the same reference numerals, and the same parts will not be described again.

In the surface-emitting laser device Z3 of the present embodiment, the current confinement structure 14 is located between the active light emitting layer 12 and the second mirror layer 13, but the current confinement structure 14 is not located in the second mirror layer 13. In detail, the surface-emitting laser device Z3 of the present embodiment further includes a current injection layer 19, and the current injection layer 19 is located between the current confinement structure 14 and the second electrode layer 16. In the present embodiment, a portion of the current injection layer 19 fills the confinement hole 14H of the current confinement structure 14.

In addition, in the present embodiment, the material constituting the current injection layer 19 is a doped semiconductor material, and the current injection layer 19 and the second conductive type doped layer 142 have opposite conductivity types. Accordingly, another PN junction (not numbered) is formed between the current injection layer 19 and the second conductive type doped layer 142. In an embodiment, the semiconductor material of the current injection layer 19 may be the same as the semiconductor material of the first conductive type doped layer 141 of the current confinement structure 14, but the application is not limited thereto. In another embodiment, the current confinement layer 14 may not be connected to the active light emitting layer 12 and may be embedded in the current injection layer 19.

The second electrode layer 16 may be electrically connected to the current injection layer 19 through the current spreading layer 17. Accordingly, when the surface emitting laser device Z1 is biased, the second conductive doped layer 142 and the first conductive doped layer 141 of the current confinement structure 14 are reversely biased with a breakdown voltage smaller than the breakdown voltage, so that the current confinement structure 14 is in a non-conductive state. Thus, current is only allowed to pass through the confining aperture 14H of the current confining structure 14.

In addition, the second mirror layer 13 of the present embodiment is provided on the current spreading layer 17 together with the second electrode layer 16. Further, the second mirror layer 13 is located in the opening 16H defined by the second electrode layer 16. In other words, the second electrode layer 16 of the present embodiment surrounds the second mirror layer 13. It should be noted that, in the present embodiment, the material constituting the second mirror layer 13 may include a semiconductor material, an insulating material, or a combination thereof. The semiconductor material may be an intrinsic semiconductor material or a doped semiconductor material, and the present application is not limited thereto. For example, the semiconductor material is silicon, indium gallium aluminum arsenide (InGaAlAs), indium gallium phosphide (InGaAsP), indium phosphide (InP), aluminum indium arsenide (inaias), aluminum gallium arsenide (AlGaAs), or aluminum gallium nitride (AlGaN), which may be selected according to the wavelength of the laser beam L. The insulating material may be an oxide or nitride, such as: the insulating material such as silicon oxide, titanium oxide, and aluminum oxide is not limited in the present application.

In one embodiment, the second mirror layer 13 may include a plurality of pairs of film layers, and the material constituting each pair of film layers may be selected from the materials described above. For example, each pair of layers may be a titanium oxide layer and a silicon oxide layer, a silicon layer and an aluminum oxide layer, or a titanium oxide layer and an aluminum oxide layer, and may be determined according to the wavelength of the laser beam L to be generated, which is not limited in the present application.

Please refer to fig. 6 and fig. 7. Fig. 6 is a schematic cross-sectional view of an surface-emitting laser device according to a fourth embodiment of the present application, and fig. 7 is an enlarged schematic view of a portion VII of fig. 6. The same or similar elements of the surface-emitting laser device Z4 of the present embodiment as those of the surface-emitting laser device Z1 of the first embodiment have the same reference numerals, and will not be described again. In this embodiment, the current confinement structure 14 may be located between the active light emitting layer 12 and the first mirror layer 11. In detail, the current confinement structure 14 may be embedded in the first mirror layer 11 and connected to the active light emitting layer 12.

As shown in fig. 7, the current confinement structure 14 includes a first conductive type doped layer 141 and a second conductive type doped layer 142, and a PN junction SA is formed between the first conductive type doped layer 141 and the second conductive type doped layer 142. In addition, the first conductive type doping layer 141 is disposed facing the first electrode layer 15, and the second conductive type doping layer 142 is disposed facing the second electrode layer 16. Accordingly, in the first mirror layer 11, the current confinement structure 14 of the present embodiment includes a zener diode (Zenordiode) formed by the first conductive type doped layer 141 and the second conductive type doped layer 142 together.

In the present embodiment, the second conductive type doped layer 142 is located between the first conductive type doped layer 141 and the active light emitting layer 12. Since the first conductive type doped layer 141 and the first mirror layer 11 have opposite conductive types, another PN junction SC is formed between the first conductive type doped layer 141 and the first mirror layer 11. For example, when the first mirror layer 11 is N-type, the first conductive type doped layer 141 is P-type, and the second conductive type doped layer 142 is N-type. In addition, the second conductive type doping layer 142 and the first mirror layer 11 may be formed of the same or different materials, and the present application is not limited thereto.

When the surface-emitting laser device Z4 is biased, the zener diode of the current confinement structure 14 is reverse biased to a voltage less than the breakdown voltage, so that the current confinement structure 14 is in a non-conductive state. Thus, current is only allowed to pass through the confining aperture 14H of the current confining structure 14. When an electrostatic discharge is generated, the zener diode of the current confinement structure 14 is turned on, regardless of whether the electrostatic current is positive or negative, to allow a majority of the electrostatic current to pass through the current confinement structure 14, thereby providing electrostatic protection to the surface-emitting laser device Z4.

Fig. 8 is a schematic enlarged view of a portion of an area-emission laser device according to another embodiment of the application. In the present embodiment, the current confinement structure 14 is located in the first mirror layer 11 and has a PIN junction, so that the same effect can be achieved. In detail, the current confinement structure 14 of the present embodiment may include a first conductive type doped layer 141, a second conductive type doped layer 142, and an intrinsic semiconductor layer 143. The intrinsic semiconductor layer 143 is located between the first conductive type doped layer 141 and the second conductive type doped layer 142. The current confinement structure 14 of the present embodiment operates in a similar manner to that of the embodiment of fig. 3, and may also provide electrostatic protection.

Fig. 9 is a schematic cross-sectional view of a surface-emitting laser device according to a fifth embodiment of the application. The same or similar elements of the surface-emitting laser device Z5 of the present embodiment and the surface-emitting laser device Z3 of the third embodiment have the same reference numerals, and will not be described again. In the present embodiment, the current confinement structure 14 is buried in the first mirror layer 11, but is not connected to the active light emitting layer 12. However, the current confinement structure 14 may be positioned closer to the active light emitting layer 12 and farther from the substrate 10. The current confinement structure 14 may be the structure shown in fig. 7 or 8. In detail, the current confinement structure 14 can be used to limit the current path and provide electrostatic protection to the surface emitting laser device Z5, as long as the first conductive doped layer 141 and the first mirror layer 11 have opposite conductive types to form a PN junction.

Fig. 10 is a flowchart of a method for manufacturing an area-emission laser device according to an embodiment of the application. In step S10, a first mirror layer is formed. In step S20, an active light emitting layer is formed on the first mirror layer. In step S30, an active light emitting layer of a current confinement structure is formed, wherein the current confinement structure defines a confinement hole and has a PN junction or a PIN junction. In step S40, a second mirror layer is formed. In step S50, a first electrode layer and a second electrode layer are formed.

It should be noted that the method for manufacturing the surface-emitting laser device according to the present embodiment can be used to manufacture the surface-emitting laser devices Z1 to Z5 according to the first to fifth embodiments. Referring to fig. 11 to 16, an example of manufacturing the surface-emitting laser device Z1 according to the first embodiment will be described.

As shown in fig. 11, a first mirror layer 11 is formed on a substrate 10. In detail, the first mirror layer 11 is formed on the epitaxial surface 10a of the substrate 10. The materials of the substrate 10 are described above and will not be described again here. The substrate 10 may have the same conductivity type as the first mirror layer 11.

As shown in fig. 12, an active light emitting layer 12 is formed on the first mirror layer 11. The active light emitting layer 12 may be formed by alternately forming a plurality of well layers and a plurality of barrier layers on the first mirror layer 11. In one embodiment, the first reflector layer 11 and the active light emitting layer 12 may be formed on the epitaxial surface 10a of the substrate 10 by chemical vapor deposition.

Referring to fig. 13 and 14, a detailed flow of forming the current confinement structure 14 by the active light emitting layer is shown. Referring to fig. 2 and 13 in combination, when the current confinement structure 14 shown in fig. 2 is required to be formed, the first conductive type doped layer 141 and the second conductive type doped layer 142 can be sequentially formed on the active light emitting layer 12. As shown in fig. 13, the first conductive type doped layer 141 and the second conductive type doped layer 142 may together form a stacked structure 14A.

In addition, when the current confinement structure 14 as shown in fig. 3 is to be formed, the intrinsic semiconductor layer 143 may be formed first after the first conductive type doped layer 141 is formed, and then the second conductive type doped layer 142 may be formed. In this case, the first conductive type doped layer 141, the intrinsic semiconductor layer 143 and the second conductive type doped layer 142 together form the stacked structure 14A.

Referring to fig. 14, in the present embodiment, a limiting hole 14H may be formed in the stacked structure 14A to expose a portion of the active light emitting layer 12. Further, the limiting hole 14H may be formed in the stacked structure 14A by an etching process. Referring to fig. 15, the second reflector layer 13 is formed on the current confinement structure 14 and the active light emitting layer 12. In detail, when the second mirror layer 13 is formed, a portion of the second mirror layer 13 fills the confining hole 14H and is connected to the active light emitting layer 12.

Referring to fig. 16, a first electrode layer 15 is formed on the bottom surface 10b of the substrate 10, and a second electrode layer 16 is formed on the second mirror layer 13, so as to manufacture the surface-emitting laser device Z1 according to the first embodiment of the present application. In this embodiment, the current spreading layer 17 and the protective layer 18 may be formed before the second electrode layer 16 is formed.

When the surface-emitting laser device Z2 of the second embodiment is to be fabricated, a portion of the second mirror layer 13 may be formed on the active light emitting layer 12, and then the current confinement layer 14 having the confinement holes 14H may be formed. Thereafter, another portion of the second mirror layer 13 is grown (regrowth) over the current confinement layer 14.

Referring to fig. 17, the steps may be continued to those of fig. 14. The manufacturing method of the embodiment of the application further comprises the following steps: a current injection layer 19 is formed on the current confinement structure 14. In the present embodiment, the step of forming the current injection layer 19 is performed before the step of forming the second mirror layer 13. As shown in fig. 17, the current injection layer 19 is formed in the confinement hole 14H of the current confinement structure 14 and connected to the active light emitting layer 12. Then, the current spreading layer 17 and the second mirror layer 13 are formed on the current injection layer 19.

Referring to fig. 18, a first electrode layer 15 is formed on the bottom surface 10b of the substrate 10 and a second electrode layer 16 is formed on the current spreading layer 17, such that the second electrode layer 16 is electrically connected to the current injection layer 19. In addition, the second electrode layer 16 may have an opening 16H corresponding to the limiting hole 14H, and the second electrode layer 16 is disposed around the second mirror layer 13. In other words, the second mirror layer 13 is located in the opening 16H defined by the second electrode layer 16. In an embodiment, after the current spreading layer 17 is formed, the second mirror layer 13 may be formed first, and then the second electrode layer 16 may be formed. In another embodiment, the steps of forming the second mirror layer 13 and forming the second electrode layer 16 may also be reversed. By performing the above steps, the surface-emitting laser device Z3 of the third embodiment can be manufactured.

When the surface-emitting laser device Z4 of the fourth embodiment is to be fabricated, the step of forming the current confinement structure 14 (S30) may be performed before the step of forming the active light emitting layer 12 (S20). When the surface-emitting laser device Z5 of the fifth embodiment is to be manufactured, a part of the first mirror layer 11 may be formed first, and then the current confinement layer 14 having the confinement holes 14H may be formed. Thereafter, another portion of the first mirror layer 11 is grown (regrowth) over the current confinement layer 14.

Advantageous effects of the applicationone of the advantages of the present application is that the surface-emitting laser device and the method for manufacturing the same can provide better reliability for the surface-emitting laser devices Z1-Z5 by the technical scheme of "the current confinement structure 14 has a PN junction or a PIN junction" or "the current confinement structure 14 has a zener diode".

Further, the current confinement structure 14 includes a first conductive type doped layer 141 and a second conductive type doped layer 142. The second conductivity type doped layer 142 has an opposite conductivity type to the second mirror layer 13, and the current confinement structure 14 faces the first mirror layer 11 with the first conductivity type doped layer 141. When the surface-emitting laser devices Z1-Z5 are biased, the second and first conductive doped layers 142 and 141 of the current confinement structure 14 are reverse biased with a breakdown voltage, such that the current confinement structure 14 is in a non-conductive state. Thus, current is only allowed to pass through the confining aperture 14H of the current confining structure 14.

When an electrostatic discharge is generated, the current confinement structure 14 may be in a conductive state, so that most of the electrostatic current passes through the current confinement structure 14. Accordingly, the current confinement structure 14 of the present embodiment not only serves to confine the current path, but also provides electrostatic discharge protection to the surface emitting laser devices Z1-Z5.

Compared with the conventional surface-emitting laser device, in the surface-emitting laser devices Z1 to Z5 according to the embodiments of the present application, the current confinement structure 14 itself can be used as an electrostatic protection structure without the need for an additional diode connected in parallel for protection. Therefore, the cost can be reduced and the space of the circuit layout of the electronic product can be saved.

In addition, since the first mirror layer 11, the current confinement structure 14, the active light emitting layer 12, and the second mirror layer 13 are all made of semiconductor materials, the difference in thermal expansion coefficients is small. Thus, the surface-emitting laser devices Z1-Z5 can be prevented from being broken due to the difference of thermal expansion coefficients after annealing treatment, and the process yield is improved. Since the oxide layer is not required in the surface-emitting laser devices Z1 to Z5 according to the embodiment of the present application, the lateral oxidation step may be omitted when manufacturing the surface-emitting laser devices Z1 to Z5 according to the embodiment of the present application, and the surface-emitting laser devices Z1 to Z5 according to the embodiment of the present application do not require the formation of lateral grooves. The manufacturing process of the surface-emitting laser devices Z1 to Z5 can be further simplified, and the manufacturing cost can be reduced. In addition, the influence of the invasion of moisture on the light-emitting characteristics of the surface-emitting laser devices Z1-Z5 can be avoided when the lateral oxidation is performed. Therefore, the surface-emitting laser devices Z1-Z5 according to the embodiment of the application can have higher reliability.

The above disclosure is only a preferred embodiment of the present application and is not intended to limit the scope of the present application, so that all equivalent technical changes made by the specification and drawings of the present application are included in the scope of the present application.

Claims (15)

1. A surface-emitting laser device, comprising:

A first mirror layer;

an active light emitting layer;

A second mirror layer, wherein the active light emitting layer is located between the first mirror layer and the second mirror layer to generate a laser beam; and

A current confinement structure has a PN junction or a PIN junction.

2. The surface-emitting laser device of claim 1, wherein the current confinement structure is located within the second mirror layer and forms another PN junction with the second mirror layer.

3. The surface-emitting laser device of claim 1, wherein the current confinement structure comprises a first conductivity-type doped layer and a second conductivity-type doped layer, the second conductivity-type doped layer and the second mirror layer having opposite conductivity types, and the current confinement structure faces the first mirror layer with the first conductivity-type doped layer.

4. The surface-emitting laser device of claim 1, wherein the current confinement structure comprises a first-conductivity-type doped layer, a second-conductivity-type doped layer, and an intrinsic semiconductor layer between the first-conductivity-type doped layer and the second-conductivity-type doped layer to form the PIN junction, the second-conductivity-type doped layer and the second mirror layer having opposite conductivities, and the current confinement structure faces the first mirror layer with the first-conductivity-type doped layer.

5. The surface-emitting laser device as claimed in claim 1, wherein the current confinement structure is located in the second mirror layer, the current confinement structure has a confinement hole, and a portion of the second mirror layer fills the confinement hole and is connected to the active light emitting layer.

6. The surface-emitting laser device according to claim 1, wherein a gap width of a material constituting the current confinement structure is larger than a gap width of a semiconductor material constituting the active light emitting layer.

7. The surface-emitting laser device of claim 1, wherein the total thickness of the current confinement structure is at least 30nm.

8. The surface-emitting laser device according to claim 1, further comprising: and a current injection layer positioned between the current limiting structure and the second reflector layer, wherein a part of the current injection layer is filled in a limiting hole of the current limiting structure, and another PN junction is formed between the current injection layer and the current limiting structure.

9. The surface-emitting laser device of claim 1, wherein the current confinement structure is located within the first mirror layer and wherein another PN junction is formed between the current confinement structure and the first mirror layer.

10. A surface-emitting laser device, comprising:

A first mirror layer;

an active light emitting layer;

a second mirror layer, wherein the active light emitting layer is located between the first mirror layer and the second mirror layer; and

A current confinement structure has a zener diode.

11. The surface-emitting laser device of claim 10, wherein the current confinement structure is located between the active light emitting layer and the second mirror layer or between the active light emitting layer and the first mirror layer and comprises a first conductivity-type doped layer and a second conductivity-type doped layer to form the zener diode, the second conductivity-type doped layer and the second mirror layer having opposite conductivity types, and the current confinement structure faces the first mirror layer with the first conductivity-type doped layer.

12. The surface-emitting laser device according to claim 1 or 10, further comprising:

A first electrode layer electrically connected to the first mirror layer; and

A second electrode layer defining a current path between the second electrode layer and the first electrode layer through the active light emitting layer, the second electrode layer having an opening defining a light emitting region, the opening corresponding to a confinement hole of the current confinement layer;

wherein at least a portion of the zener diode is located on the current path.

13. A method for manufacturing a surface-emitting laser device, the method comprising:

Forming a first reflector layer;

Forming an active light emitting layer on the first reflector layer;

Forming a current limiting structure, wherein the current limiting structure defines a limiting hole and is provided with a PN junction or a PIN junction; and

A second mirror layer is formed.

14. The method of manufacturing a surface-emitting laser device according to claim 13, wherein the step of forming the current confinement structure includes:

Forming a first conductive type doped layer, wherein the first conductive type doped layer and the first reflecting mirror layer have opposite conductive types;

forming a second conductive type doped layer, wherein the first conductive type doped layer and the second conductive type doped layer together form a laminated structure; and

And forming the limiting hole in the laminated structure.

15. The method of manufacturing a surface-emitting laser device according to claim 13, wherein the step of forming the current confinement structure further comprises:

Forming a first conductive type doped layer, wherein the first conductive type doped layer and the first reflecting mirror layer have opposite conductive types;

forming an intrinsic semiconductor layer on the first conductive type doped layer;

forming a second conductive type doped layer on the intrinsic semiconductor layer to form a laminated structure; and

The localized pores are formed in the laminate structure.