TWI770913B - VCSEL laser with multiple tunnel junctions and method of making the same - Google Patents

Abstract

The present application provides a VCSEL laser with multiple tunnel junctions and a preparation method thereof. The VCSEL laser includes: an epitaxial structure and a positive electrode and a negative electrode electrically connected to the epitaxial structure; the epitaxial structure includes: a substrate; a first reflector and a second reflector located above the substrate , wherein a reflection cavity is arranged between the first reflector and the second reflector; a plurality of active regions and a plurality of tunnel junctions are formed in the reflection cavity, and the plurality of active regions and The plurality of tunnel junctions are alternately arranged in the reflection cavity; and at least two confinement layers are formed in the reflection cavity, and the at least two confinement layers respectively have openings, wherein the at least two confinement layers have openings. At least some of the openings have different pore diameters. In this way, the VCSEL laser can take into account the size of the far-field beam divergence angle while having high photoelectric conversion efficiency.

Description

VCSEL laser with multiple tunnel junctions and method of making the same

The present application relates to the field of semiconductors, and more particularly, to a VCSEL laser with multiple tunnel junctions and a method for fabricating the same.

VCSEL (Vertical-Cavity Surface-Emitting Laser, Vertical Cavity Surface Emitting Laser) is a semiconductor laser that forms a resonant cavity in the vertical direction of the substrate and emits laser light in the vertical direction. VCSEL lasers, especially VCSEL lattice devices comprising multiple VCSEL units, are widely used in industries such as consumer electronics, industrial, medical, and the like. Based on the number of tunnel junctions, VCSEL devices can be divided into single-junction VCSEL devices and multi-junction VCSEL devices, as the name suggests, a single-junction VCSEL device means a VCSEL cell in a VCSEL device with one tunnel junction, and a multi-junction VCSEL device means a VCSEL cell in a VCSEL device Has multiple tunnel junctions.

The market has always demanded high photoelectric conversion efficiency (Power-converted-efficiency: PCE) for high-power VCSEL lattice devices. It is difficult for single-junction VCSEL devices to achieve high PCE while achieving high power due to their own resistance characteristics. Moreover, driving a single-junction high-power VCSEL device requires a large current. In practical applications, the algorithm has high requirements on the rise time of the current pulse, that is, the design of the driving circuit board puts forward high requirements. technically difficult to achieve.

Compared with the single-junction VCSEL device, the multi-junction VCSEL device can alleviate the above-mentioned defects of the single-junction VCSEL device to a certain extent under specific use conditions. That is, for the specified It can drive multi-junction VCSEL devices with relatively small current, and the corresponding PCE can also be improved due to the reduction of operating current.

However, since the geometric cavity length of the multi-junction VCSEL device is many times that of the single-junction VCSEL device, the far-field beam divergence angle of the actual multi-junction VCSEL device cannot meet the design requirements. That is, for a multi-junction VCSEL device, it is difficult to achieve both performance in terms of photoelectric conversion efficiency and far-field beam divergence.

Therefore, a new type of VCSEL device that can take into account both the photoelectric conversion efficiency and the far-field beam divergence angle is required.

An advantage of the present application is to provide a VCSEL laser with multiple tunnel junctions and a method for fabricating the same, wherein the VCSEL laser can take into account the size of the far-field beam divergence angle while having high photoelectric conversion efficiency.

In order to achieve at least one of the above advantages, the present application provides a VCSEL laser with multiple tunnel junctions, which includes: an epitaxial structure and a positive electrode and a negative electrode electrically connected to the epitaxial structure;

Wherein, the epitaxial structure includes:

substrate;

a first reflector and a second reflector located above the substrate, wherein a reflection cavity is provided between the first reflector and the second reflector;

a plurality of active regions and a plurality of tunnel junctions formed in the reflective cavity, the plurality of active regions and the plurality of tunnel junctions being alternately arranged in the reflective cavity; and

At least two confinement layers formed in the reflective cavity, the at least two confinement layers are divided into It has openings, wherein at least some of the openings in the at least two confinement layers have different pore diameters.

In the VCSEL laser with multiple tunnel junctions according to the present application, the confinement layers are respectively formed over each of the active regions, and the number of the confinement layers is consistent with the number of the active regions.

In the VCSEL laser with multiple tunnel junctions according to the present application, the confinement layer is selectively formed over part of the active regions, and the number of the confinement layers is smaller than the number of the active regions.

In the VCSEL laser with multiple tunnel junctions according to the present application, the aperture of the openings ranges from 1 um to 100 um.

In the VCSEL laser with multiple tunnel junctions according to the present application, the aperture of the openings ranges from 3um to 50um.

In the VCSEL laser with multiple tunnel junctions according to the present application, the aperture difference between the openings ranges from 0.1 um to 95 um.

In the VCSEL laser with multiple tunnel junctions according to the present application, the aperture difference between the openings ranges from 0.5um to 20um.

In the VCSEL laser with multiple tunnel junctions according to the present application, the aperture sizes between the openings of the at least two confinement layers are not equal to each other.

In the VCSEL laser with multiple tunnel junctions according to the present application, the opening of the confinement layer closest to the second reflector in the at least one confinement layer has the smallest aperture.

In the VCSEL laser with multiple tunnel junctions according to the present application, the at least two confinement layers include at least one oxidation confinement layer formed by an oxidation process.

In the VCSEL laser with multiple tunnel junctions according to the present application, the at least two confinement layers include at least one ion confinement layer formed by an ion implantation process.

In the VCSEL laser with multiple tunnel junctions according to the present application, the at least two confinement layers include at least one oxidation confinement layer formed by an oxidation process, and the at least two confinement layers include at least one oxide confinement layer formed by an ion implantation process. Ion confinement layer.

In the VCSEL laser with multiple tunnel junctions according to the present application, the at least two confinement layers are oxidation confinement layers all formed by an oxidation process.

In the VCSEL laser with multiple tunnel junctions according to the present application, the spacing between the oxidation confinement layers is equal to 0.5*an integer multiple of the wavelength of the laser light generated by the VCSEL laser divided by the weighted sum of the refractive indices of the semiconductors therebetween.

According to another aspect of the present application, there is also provided a method for preparing a VCSEL laser with multiple tunnel junctions, comprising:

An epitaxial structure is formed by an epitaxial growth process, which includes a substrate, a first reflector and a second reflector located above the substrate, and formed between the first reflector and the second reflector a plurality of active regions and a plurality of tunnel junctions, the plurality of active regions and the plurality of tunnel junctions are alternately arranged; and

At least a carbon dioxide confinement layer is formed between the first reflector and the second reflector through an oxidation process, and the at least carbon dioxide confinement layers respectively have openings, wherein at least part of the openings are among the openings. have different apertures.

In the preparation method according to the present application, the oxidation confinement layers are respectively formed over each of the active regions, and the number of the oxidation confinement layers is consistent with the number of the active regions.

In the production method according to the present application, the oxidation confinement layer is selectively topographical Formed over a portion of the active regions, the number of the oxidation confinement layers is smaller than the number of the active regions.

In the preparation method according to the present application, the pore diameter of the openings ranges from 1 um to 100 um.

In the preparation method according to the present application, the pore diameter of the openings ranges from 3um to 50um.

In the preparation method according to the present application, the pore diameter difference between the openings ranges from 0.1 um to 95 um.

In the preparation method according to the present application, the pore diameter difference between the openings ranges from 0.5um to 20um.

In the preparation method according to the present application, the openings of the oxidation confinement layer closest to the second reflector in the at least dioxide confinement layer have the smallest pore diameter.

Further objects and advantages of the present application will be fully realized by an understanding of the ensuing description and drawings.

These and other objects, features and advantages of the present application are fully embodied by the following detailed description, drawings and claims.

1P: Negative Electrode

2P: Substrate

3P:N-DBR

4P: Active area

5P: Oxidation limiting layer

6P:P-DBR

7P: Positive Electrode

8P: Tunnel Junction

10: Epitaxial structure

11: Substrate

12: First reflector

13: Second reflector

14: Active area

15: Tunnel Junction

16: Restriction Layer

16A: Oxidation limiting layer

16B: Ion confinement layer

100: Reflective cavity

160: Opening

20: Positive electrode

30: Negative Electrode

These and/or other aspects and advantages of the present application will become clearer and easier to understand from the following detailed description of embodiments of the present application in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates a schematic structural diagram of a conventional single-junction VCSEL unit.

FIG. 2 illustrates a schematic structural diagram of a conventional multi-junction VCSEL unit.

FIG. 3 illustrates another structural schematic diagram of a conventional multi-junction VCSEL unit.

FIG. 4A illustrates a schematic structural diagram of a VCSEL laser according to an embodiment of the present application.

FIG. 4B illustrates a schematic structural diagram of a variant implementation of a VCSEL laser according to an embodiment of the present application.

FIG. 4C illustrates a schematic structural diagram of another variant implementation of the VCSEL laser according to the embodiment of the present application.

FIG. 5 illustrates a schematic diagram of a performance curve of a VCSEL laser according to an embodiment of the present application.

FIG. 6 illustrates another schematic diagram of a performance curve of a VCSEL laser according to an embodiment of the present application.

FIG. 7 illustrates a schematic structural diagram of a VCSEL laser according to another embodiment of the present application.

FIG. 8 illustrates a schematic structural diagram of a VCSEL laser according to yet another embodiment of the present application.

FIG. 9 illustrates a schematic structural diagram of a VCSEL laser according to yet another embodiment of the present application.

FIG. 10 illustrates a schematic diagram of a method for fabricating a VCSEL laser according to an embodiment of the present application.

The terms and words used in the following specification and claims are not limited to the bibliographical meanings, but are merely used by the applicant to enable a clear and consistent understanding of this application. Therefore, it will be apparent to those skilled in the art that this is for illustrative purposes only and not for purposes such as the appended claims and The following descriptions of various embodiments of the present application are provided for the purposes of the present application with the limitations defined by their equivalents.

It should be understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be one. The number may be plural, and the term "one" should not be understood as a limitation on the number.

Although ordinals such as "first," "second," etc. will be used to describe various elements, those elements are not limited herein. This term is only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the teachings of the present inventive concept. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The terminology used herein is for the purpose of describing the various embodiments only and is not intended to be limiting. As used herein, the singular form is intended to include the plural form as well, unless the context clearly dictates an exception. It will also be understood that the terms "comprising" and/or "having" when used in this specification designate the presence of stated features, numbers, steps, operations, elements, elements or combinations thereof, without excluding one or more other features , number, step, operation, element, presence or addition of elements or groups thereof.

Application overview

As mentioned earlier, it is difficult for single-junction VCSEL devices to achieve high PCE while achieving high power due to their own resistance characteristics. FIG. 1 illustrates a schematic structural diagram of a single-junction VCSEL unit in a conventional single-junction VCSEL device. As shown in FIG. 1, an existing single-junction VCSEL unit includes, from top to bottom, a negative electrode 1P, a substrate 2P, an N-DBR 3P, an active region 4P, an oxidation confinement layer 5P, a P-DBR 6P and a positive electrode 7P, in which, during operation, the active area 4P memory is inversely in particle number If the gain provided by the laser medium is sufficient to exceed the loss, when the current is injected through the positive electrode 7P and the negative electrode 1P, the light intensity will continue to increase, and the electrons at the bottom of the conduction band in the high energy state transition to the low energy band. , as the specific wavelength of light bounces back and forth between P-DBR 6P and N-DBR 3P, and the amplification process repeats itself, forming a laser. In particular, in existing single junction VCSEL cells a single tunnel junction is formed in the active region.

FIG. 2 illustrates a schematic structural diagram of a conventional multi-junction VCSEL unit. As shown in FIG. 2 , compared to the single-junction VCSEL unit as shown in FIG. 1 , the multi-junction VCSEL unit includes a plurality of active regions 4P and a plurality of active regions arranged alternately between the N-DBR 3P and P-DBR 6P Each tunnel junction 8P. For example, in the multi-junction VCSEL cell shown in FIG. 2, the multi-junction VCSEL cell is implemented as a three-junction VCSEL cell including three active regions 4P and two tunnel junctions 8P sandwiched between each between the two active regions 4P.

Those of ordinary skill in the art should know that the tunnel junction works based on the tunnel effect. The so-called tunnel effect means that when the carrier energy is low (less than the potential barrier height, ie E<V), the thickness of the thin film material itself is very small (10 nm). even thinner), the carriers can still pass through the thin film material with a certain probability. Compared with single-junction VCSEL devices, multi-junction VCSEL devices can be driven with a relatively small current for a given power requirement, and the corresponding PCE can also be improved due to the reduction of operating current. Specifically, for a specified power requirement, for example, a single-junction VCSEL device requires 10A current drive, a dual-junction VCSEL device only needs about 5A current drive, and a three-cell VCSEL device only needs 3A~4A drive current.

However, since the geometric cavity length of the multi-junction VCSEL device is many times that of the single-junction VCSEL device, the far-field beam divergence angle of the actual multi-junction VCSEL device cannot meet the design requirements. In order to solve the problem of excessive far-field beam divergence in multi-junction VCSEL devices, some manufacturers will try to reduce oxidation The number of layers 5P is limited, as shown in FIG. 3 . In the multi-junction VCSEL cell as shown in FIG. 3, only one oxidation confinement layer 5P is configured. However, in the actual test process, the inventors of the present application found that if the number of oxidation confinement layers is reduced, the luminous efficiency will be reduced, that is, the photoelectric conversion efficiency will become very low again, which will lose the unique characteristics of multi-junction VCSEL lasers. Advantage. The analysis shows that the purpose of the oxidation confinement layer is to confine the carriers, and reducing the number of the oxidation confinement layer too much will make the confinement of the carriers too small, which will increase the current threshold and reduce the photoelectric conversion efficiency. That is, the existing solutions still cannot take into account the performance of multi-junction VCSEL devices in terms of photoelectric conversion efficiency and far-field beam divergence.

Based on this, the inventors of the present application tried to change the configuration of the confinement layer (the confinement layer here includes not only the oxidation confinement layer, but also the ion confinement layer formed by the ion placement process) to achieve high photoelectric conversion efficiency and far-field beam efficiency. The performance of the two aspects of the dispersion angle is balanced.

Through theoretical research and experimental tests, the inventors of the present application found that by changing the aperture diameter of the confinement layer and/or changing the positional setting of the confinement layer relative to the active region and the tunnel junction, the photoelectric conversion efficiency and far-field beam dispersion of the VCSEL device can be achieved The performance of both angles and quantities is balanced. Specifically, on a theoretical level, as mentioned above, the purpose of the oxide confinement layer is to confine the carriers. If the confinement of the carriers becomes too small, the threshold value will increase and the photoelectric conversion efficiency will become lower, but on the contrary, If confinement is too much, it will affect the distribution of carriers and thus the mode of light, thus making the far-field divergence angle uncontrolled. Therefore, the inventors of the present application adjusted the aperture diameter of the confinement layer (more specifically, the aperture diameter of some of the confinement layers are not equal), and/or, changed the positional setting of the confinement layer relative to the active region and the tunnel junction (also That is, adjusting the quantity and arrangement position of the confinement layers) to achieve both the performance of the VCSEL device in terms of photoelectric conversion efficiency and far-field beam divergence.

Based on this, the present application proposes a VCSEL laser with multiple tunnel junctions, It includes: an epitaxial structure and a positive electrode and a negative electrode electrically connected to the epitaxial structure; wherein, the epitaxial structure includes: a substrate; a first reflector and a second reflector located above the substrate, wherein , a reflection cavity is arranged between the first reflector and the second reflector; a plurality of active regions and a plurality of tunnel junctions are formed in the reflection cavity, and the plurality of active regions and the A plurality of tunnel junctions are alternately arranged in the reflection cavity; and at least two confinement layers are formed in the reflection cavity, and the at least two confinement layers respectively have openings, wherein the at least two confinement layers of the at least two confinement layers have openings respectively. At least some of the openings have different pore diameters.

Schematic VCSEL laser

FIG. 4A illustrates a schematic structural diagram of a VCSEL laser according to an embodiment of the present application. As shown in FIG. 4A , the VCSEL laser according to the embodiment of the present application has multiple tunnel junctions. Here, the tunnel junction works based on the tunnel effect. The so-called tunnel effect means that when the carrier energy is low (less than the potential barrier height, that is, E<V), the thickness of the thin film material itself is very small (10nm or even thinner). ), the carriers can still pass through the thin film material with a certain probability.

Particularly, in the VCSEL laser as shown in FIG. 4A , the VCSEL laser includes one VCSEL unit as an example, and the VCSEL unit has a three-junction tunnel junction.

It should be understood that, in other examples of the present application, the VCSEL laser may further include a greater number of VCSEL units, and of course, the VCSEL unit may include a greater number or a lesser number of tunnel junctions. limited by this application. Typically, in a VCSEL laser, the number of tunnel junctions is one less than the number of active regions, for example, in the VCSEL laser as shown in Figure 4A, the VCSEL unit has two tunnel junctions and three active regions .

In the VCSEL laser shown in FIG. 4A, the VCSEL laser It includes: an epitaxial structure 10 generated by an epitaxial growth process (eg, metal organic compound chemical vapor deposition) and a positive electrode 20 and a negative electrode 30 electrically connected to the epitaxial structure 10, wherein the epitaxial structure 10 includes: A substrate 11, a first reflector 12 and a second reflector 13 located above the substrate 11, a reflection cavity 100 is provided between the first reflector 12 and the second reflector 13, and is formed in the A plurality of active regions 14 and a plurality of tunnel junctions 15 in the reflective cavity 100, the plurality of active regions 14 and the plurality of tunnel junctions 15 are alternately arranged in the reflective cavity 100, and formed in the At least two confinement layers 16 in the reflective cavity 100, the at least two confinement layers 16 respectively have openings 160, wherein at least some of the openings 160 in the at least two confinement layers 16 have different openings 160. aperture.

Specifically, in the VCSEL laser shown in FIG. 4A , the VCSEL laser includes three of the active regions 14 and two of the tunnel junctions 15 , wherein the two tunnel junctions 15 and the Three active regions 14 are alternately arranged in the reflection cavity 100 formed by the first reflector 12 and the second reflector 13 , that is, each layer of the tunnel junction 15 is sandwiched between two of the between the active regions 14 .

In the VCSEL laser, the active region 14 includes quantum wells (of course, in other examples of the present application, the active region 14 may include quantum dots), which may be composed of AlInGaAs (eg, AlInGaAs, GaAs, AlGaAs) and InGaAs), InGaAsP (for example, InGaAsP, GaAs, InGaAs, GaAsP, and GaP), GaAsSb (for example, GaAsSb, GaAs, and GaSb), InGaAsN (for example, InGaAsN, GaAs, InGaAs, GaAsN, and GaN), or AlInGaAsP (for example, AlInGaAsP , AlInGaAs, AlGaAs, InGaAs, InGaAsP, GaAs, InGaAs, GaAsP and GaP). Of course, in this embodiment of the present application, the active region 14 may also be formed by other compositions for forming a quantum well layer.

In the VCSEL laser, the first reflector 12 and the second reflector 13 each comprise a system of alternating layers of materials of different refractive indices, which form a Distributed Bragg Reflector. The choice of material for the alternating layers depends on the desired operating wavelength of the laser. In a specific example of the present application, the first reflector 12 and the second reflector 13 may be formed of alternating layers of AlGaAs with a high aluminum content and AlGaAs with a low aluminum content. It is worth mentioning that the optical thickness of the alternating layers is equal to or approximately equal to 1/4 of the operating wavelength of the laser. Particularly, in the embodiment of the present application, the first reflector 12 is an N-type doped distributed Bragg reflector, that is, N-DBR, and the second reflector 13 is a P-type doped distributed Bragg reflector Bragg reflector, that is, P-DBR, wherein the materials of the P-type doped DBR and the N-type doped DBR include but are not limited to: InGaAsP/InP, AlGaInAs/AlInAs, AlGaAsSb/AlAsSb, GaAs /AlGaAs, Si/MgO and Si/Al2O3 etc.

In the VCSEL laser, the substrate 11 may include, but is not limited to, a silicon substrate 11, a sapphire substrate 11, a gallium arsenide substrate 11, and the like.

As shown in FIG. 4A , the plurality of active regions 14 are sandwiched in the reflective cavity 100 between the first reflector 12 and the second reflector 13 , wherein the photons are excited after being excited. The back and forth reflection in the reflective cavity 100 is continuously repeated and amplified to form laser oscillation, thereby forming a laser. Those of ordinary skill in the art should know that through the configuration and design of the first reflector 12 and the second reflector 13, the exit direction of the laser light can be selectively controlled, for example, the exiting direction of the laser light from the second reflector 13 (ie, , exit from the top surface of the VCSEL laser) or, exit from the first reflector 12 (ie exit from the bottom surface of the VCSEL laser). In the embodiment of the present application, the first reflector 12 and the second reflector 13 are designed so that after the laser oscillates in the reflective cavity 100, it exits from the second reflector 13, that is, all the The VCSEL laser is positive A semiconductor laser that emits light.

In order to confine the current mode and light output mode of the VCSEL laser, the VCSEL laser according to the embodiment of the present application further includes at least two confinement layers 16 formed in the reflective cavity 100 , and the at least two confinement layers 16 respectively have openings. The holes 160, wherein at least some of the openings 160 of the at least two confinement layers 16 have different diameters. Particularly, in the VCSEL laser as shown in FIG. 4A , the at least two confinement layers 16 are at least two oxide confinement layers 16A formed over a part of the active region 14 by an oxidation process, wherein the The degree of oxidation of the oxidation confinement layer 16A determines the pore size of the openings 160 of the oxidation confinement layer 16A.

More specifically, in the VCSEL laser as shown in FIG. 4A , the number of the oxidation confinement layers 16A is equal to the number of the active regions 14 , that is, in the VCSEL laser as shown in FIG. 4A , all The VCSEL laser includes three oxide confinement layers 16A formed over each of the active regions 14, respectively.

Different from the existing multi-junction VCSEL unit, in the embodiment of the present application, at least some of the openings 160 of the at least the dioxide confinement layer 16A have different pore diameters. In the application embodiment, the VCSEL laser has an asymmetrical oxide confinement layer 16A structure.

Through the configuration of the asymmetric oxide layer structure, it can be seen from the measurement that the VCSEL laser can achieve both performance in terms of photoelectric conversion efficiency and far-field beam divergence. Specifically, as shown in Figures 5 and 6, the VCSEL laser can be driven at a current of 2.7A, with a far-field beam divergence angle of 19°, an optical power of 6.5W, and a photoelectric conversion efficiency of up to 47%.

More specifically, in the embodiment of the present application, the at least the dioxide confinement layer 16A The aperture sizes of the plurality of openings 160 may be all unequal. For example, in the example shown in FIG. 4A , the apertures of the three openings 160 decrease sequentially from top to bottom. Alternatively, in the example shown in FIG. 4B , the aperture sizes of the three openings 160 increase sequentially from top to bottom. Alternatively, in the example shown in FIG. 4C , the aperture sizes of the three openings 160 first decrease and then increase from top to bottom. Of course, in other examples of the present application, the aperture sizes of the plurality of openings 160 of the plurality of oxidation confinement layers 16A may be partially equal, which is not limited by the present application.

More specifically, in the embodiment of the present application, the pore size of the openings 160 ranges from 1 um to 100 um, and preferably, the pore size of the openings 160 ranges from 3 um to 50 um. Further, in the embodiment of the present application, the pore diameter difference between the openings 160 ranges from 0.1 um to 95 um, and preferably, the pore diameter difference between the openings 160 ranges from 0.5 um to 20 um. Moreover, in the embodiment of the present application, the spacing between the oxidation confinement layers 16A is equal to 0.5*the integer multiple of the wavelength of the laser generated by the VCSEL laser divided by the weighted sum of the refractive indices of the semiconductors therebetween, where the semiconductor represents For the semiconductor material between the two oxidation confinement layers 16A, the weighted sum represents the sum of the products of the refractive indices of the semiconductors with the preset weights. The distance between the oxidation confinement layer 16A and the active region 14 is 0.25* odd multiples of the wavelength of the laser light generated by the VCSEL laser divided by the refractive index of the substrate 11 . For example, when the refractive index of the GaAs substrate 11 is 3.4 and the multiple is 3, the distance between the oxidation confinement layer 16A and the active region 14 is 0.25*940/3.4*3˜200 nm.

More preferably, in the embodiment of the present application, the opening 160 of the oxidation confinement layer 16A closest to the second reflector 13 in the at least one oxidation confinement layer 16A has the smallest diameter.

In a specific implementation, under the same oxidation process conditions, the oxidation confinement layer 16A with different pore diameters can be controlled by controlling the thickness of the oxidation confinement layer 16A or the oxidation confinement This is achieved by the aluminum content in layer 16A. Particularly, in the embodiments of the present application, the aluminum content of the oxidation limiting layer 16A ranges from 95% to 100%, and the thickness thereof ranges from 10 nm to 50 nm.

It is worth mentioning that, in the embodiment of the present application, since the oxidation confinement layer 16A has different apertures, the amount of oxidation of the entire oxidation confinement layer 16A can be reduced, so that the oxidation confinement layer 16A can be reduced. The overall stress introduced by 16A is also reduced, so the reliability of the VCSEL laser is improved.

In order to further avoid the reliability problem caused by excessive oxidation of the confinement layer 16A, in other examples of the present application, the relative positional relationship between the oxidation confinement layer 16A and the active region 14 and the tunnel junction 15 may be changed. FIG. 7 is a schematic structural diagram of a VCSEL laser according to another embodiment of the present application, wherein the VCSEL laser shown in FIG. 7 is a modified embodiment of the VCSEL laser shown in FIGS. 4A to 4C . Specifically, in the VCSEL laser as shown in FIG. 7 , the oxidation confinement layer 16A is selectively formed over a part of the active region 14 , that is, the amount of the oxidation confinement layer 16A is smaller than the amount of the oxidation confinement layer 16A. The number of active regions 14 (it should be noted that the number of the oxidation confinement layers 16A here is still greater than or equal to 2).

That is, in other examples of the present application, one of the oxidation confinement layers 16A is not configured for each of the active regions 14, so that the photoelectric conversion efficiency of the VCSEL laser can be guaranteed, and its stability can also be guaranteed. . This approach is more important for VCSEL devices with more tunnel junctions 15 .

It is worth mentioning that, in this embodiment, when one of the oxidation confinement layers 16A is not configured for each of the active regions 14 , the apertures of the oxidation confinement layers 16A can be configured to be all equal. That is, when the oxidation confinement layer 16A is not configured for each of the active regions 14, the oxidation confinement layer 16A may also be configured to have a symmetric structure, for which it is not necessary to limited by this application.

Further, in the embodiment of the present application, in order to turn on the epitaxial structure 10 to generate laser light, the VCSEL laser further includes a positive electrode 20 and a negative electrode 30 electrically connected to the epitaxial structure 10 , wherein the positive electrode 20 is formed on the upper surface of the epitaxial structure 10 , and the second electrode is formed on the lower surface of the epitaxial structure 10 . More specifically, in the embodiment of the present application, the first electrode is formed above the second reflector 13 of the epitaxial structure 10 ; the first electrode is formed on the lining of the epitaxial structure 10 below the bottom 11.

It is worth mentioning that, in other examples of the present application, the positive electrode 20 and the negative electrode 30 may also be formed at other positions of the VCSEL laser, which is not limited by the present application.

FIG. 8 illustrates a schematic structural diagram of a VCSEL laser according to yet another embodiment of the present application. Compared with the VCSEL lasers shown in FIGS. 4A to 4B and FIG. 7 , in the embodiment of the present application, the confinement layer 16 in the VCSEL laser is an ion confinement layer 16 formed by an ion implantation process.

As shown in FIG. 8 , in the embodiment of the present application, the number of the ion confinement layers 16 is equal to the number of the active regions 14 , that is, in the VCSEL laser as shown in FIG. 8 , it includes three ions A confinement layer 16B is formed over each of the active regions 14 , respectively. Consistently, in the embodiment of the present application, at least some of the openings 160 of the at least two ion confinement layer 16B have different apertures, that is, the VCSEL laser has asymmetrical Ion confinement layer 16B structure.

More specifically, in the embodiment of the present application, the aperture sizes of the plurality of openings 160 of the plurality of ion confinement layers 16B may be all unequal. Of course, the plurality of ion confinement layers 16B The aperture sizes of the plurality of openings 160 may be partially equal, which is not limited by the present application.

More specifically, in the embodiment of the present application, the pore size of the openings 160 ranges from 1 um to 100 um, and preferably, the pore size of the openings 160 ranges from 3 um to 50 um. Further, in the embodiment of the present application, the pore diameter difference between the openings 160 ranges from 0.1 um to 95 um, and preferably, the pore diameter difference between the openings 160 ranges from 0.5 um to 20 um. More preferably, the openings 160 of the ion confinement layer 16B closest to the second reflector 13 in the at least one ion confinement layer 16B have the smallest diameter.

In a specific implementation, the implanted ions include, but are not limited to, hydrogen ions, oxygen ions, etc., which can be implanted into the reflection cavity 100 from the upper surface of the second reflector 13, and the ions are implanted at a depth that can be Based on energy control at the time of injection. Specifically, when the implantation is deeper, the energy can be increased so that the implanted ions are closer to the first reflector 12, and when the implantation is shallower, the energy can be reduced so that the implanted ions are closer to the first reflector 12 the second reflector 13 . Accordingly, the size of the opening 160 of the ion confinement layer 16B can be controlled based on the energy of the implanted ions and the amount of the implanted ions.

It is worth mentioning that in other examples of the present application, the confinement layer 16 may also be a combination of the ion confinement layer 16B and the oxidation confinement layer 16A, that is, the at least two confinement layers 16 include at least one through oxidation The oxidation confinement layer 16A is formed by the process, and the at least two confinement layers 16 include at least one ion confinement layer 16B formed by an ion implantation process, as shown in FIG. 9 .

To sum up, the VCSEL laser based on the embodiments of the present application is explained by adjusting the aperture of the opening 160 of the confinement layer 16 and/or adjusting the confinement layer 16 relative to the distance between the active region 14 and the tunnel junction 15 position settings to realize VCSEL devices in photoelectric conversion efficiency and far-field The performance of the two aspects of the beam divergence angle is balanced.

Schematic preparation method

FIG. 10 illustrates a schematic diagram of a method for fabricating a VCSEL laser according to an embodiment of the present application.

As shown in FIG. 10 , the preparation process according to the embodiment of the present application includes: firstly, an epitaxial structure 10 is formed by an epitaxial growth process, which includes: a substrate 11 , a first reflector 12 located above the substrate 11 , and a second A reflector 13, and a plurality of active regions 14 and a plurality of tunnel junctions 15 formed between the first reflector 12 and the second reflector 13, the plurality of active regions 14 and the A plurality of tunnel junctions 15 are alternately arranged; then, at least a carbon dioxide confinement layer 16A is formed between the first reflector 12 and the second reflector 13 through an oxidation process, and the at least carbon dioxide confinement layers 16A are respectively There are openings 160, wherein at least some of the openings 160 have different pore diameters.

In one example, in the above-mentioned method for fabricating a VCSEL laser, the oxidation confinement layer 16A is formed over each of the active regions 14 respectively, and the number of the oxidation confinement layers 16A is the same as that of the active region 14 . the same number.

In one example, in the above-mentioned method for fabricating a VCSEL laser, the oxidation confinement layer 16A is selectively formed over a portion of the active region 14 , and the amount of the oxidation confinement layer 16A is smaller than that of the active region. 14 quantity.

In an example, in the above-mentioned manufacturing method of a VCSEL laser, the aperture of the opening 160 ranges from 1 um to 100 um.

In an example, in the above-mentioned manufacturing method of a VCSEL laser, the aperture of the opening 160 ranges from 3um to 50um.

In an example, in the above-mentioned method for fabricating a VCSEL laser, the aperture difference between the openings 160 ranges from 0.1 um to 95 um.

In an example, in the above-mentioned manufacturing method of a VCSEL laser, the aperture difference between the openings 160 ranges from 0.5 um to 20 um.

In an example, in the above-mentioned method for fabricating a VCSEL laser, the opening 160 of the oxidation confinement layer 16A in the at least dioxide confinement layer 16A that is closest to the second reflector 13 has the smallest aperture.

In conclusion, the manufacturing method of the VCSEL laser based on the embodiments of the present application has been clarified, which can manufacture the VCSEL laser as described above. It should be noted that the preparation process shown in FIG. 10 is exemplified by the preparation of a VCSEL laser in which the confinement layer 16 is the oxidation confinement layer 16A. It should be understood that when the confinement layer 16 is the ion confinement layer 16B or the confinement layer When the reference numeral 16 is the combination of the ion confinement layer 16B and the oxidation confinement layer 16A, the corresponding preparation process can be known by simple changes, which will not be repeated here.

The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, advantages, effects, etc. mentioned in the present application are only examples rather than limitations, and these advantages, advantages, effects, etc., are not considered to be Required for each embodiment of this application. In addition, the specific details disclosed above are only for the purpose of example and easy understanding, rather than limiting, and the above-mentioned details do not limit the application to be implemented by using the above-mentioned specific details.

The block diagrams of devices, apparatus, apparatuses, and systems referred to in this application are merely illustrative examples and are not intended to require or imply that the connections, arrangements, or configurations must be in the manner shown in the block diagrams. As those skilled in the art will appreciate, these means, apparatuses, apparatuses, systems may be connected, arranged, configured in any manner. such as "includes", "includes", "has" The words etc. are open-ended words meaning "including but not limited to" and are used interchangeably therewith. As used herein, the words "or" and "and" refer to and are used interchangeably with the word "and/or" unless the context clearly dictates otherwise. As used herein, the term "such as" refers to and is used interchangeably with the phrase "such as but not limited to".

It should also be pointed out that in the apparatus, equipment and method of the present application, each component or each step can be decomposed and/or recombined. These disaggregations and/or recombinations should be considered as equivalents of the present application.

The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the application. Therefore, this application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The foregoing description has been presented for the benefit of illustration and description. Furthermore, this description is not intended to limit the embodiments of the application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

10: Epitaxial structure

11: Substrate

12: First reflector

13: Second reflector

14: Active area

15: Tunnel Junction

16: Restriction Layer

16A: Oxidation limiting layer

100: Reflective cavity

160: Opening

20: Positive electrode

30: Negative Electrode

Claims (22)

A VCSEL laser with multiple tunnel junctions, comprising: an epitaxial structure and a positive electrode and a negative electrode electrically connected to the epitaxial structure; wherein, the epitaxial structure includes: a substrate; located above the substrate The first reflector and the second reflector, wherein a reflection cavity is arranged between the first reflector and the second reflector; a plurality of active regions and a plurality of tunnels are formed in the reflection cavity junction, the plurality of active regions and the plurality of tunnel junctions are alternately arranged in the reflection cavity; and at least two confinement layers formed in the reflection cavity, the at least two confinement layers respectively have openings, Wherein, at least some of the openings in the at least two confinement layers have different apertures, so as to take into account the photoelectric conversion efficiency and the far-field beam divergence angle. The VCSEL laser with multiple tunnel junctions of claim 1, wherein the confinement layers are respectively formed over each of the active regions, and the number of the confinement layers is consistent with the number of the active regions . The VCSEL laser with multiple tunnel junctions of claim 1, wherein the confinement layer is selectively formed over a portion of the active regions, the number of the confinement layers being less than the number of the active regions . The VCSEL laser with multiple tunnel junctions according to claim 2 or 3, wherein the aperture of the openings ranges from 1 um to 100 um. The VCSEL laser with multiple tunnel junctions according to claim 4, wherein the aperture of the openings ranges from 3um to 50um. The VCSEL laser with multiple tunnel junctions according to claim 5, wherein the aperture difference between the openings ranges from 0.1 um to 95 um. The VCSEL laser with multiple tunnel junctions according to claim 6, wherein the aperture difference between the openings ranges from 0.5um to 20um. The VCSEL laser with multiple tunnel junctions according to claim 4, wherein the aperture sizes between the openings of the at least two confinement layers are not equal to each other. The VCSEL laser with multiple tunnel junctions according to claim 2 or 3, wherein the opening of the confinement layer closest to the second reflector among the at least two confinement layers has the smallest aperture. The VCSEL laser with multiple tunnel junctions according to claim 1, wherein the at least two confinement layers comprise at least one oxidation confinement layer formed by an oxidation process. The VCSEL laser with multiple tunnel junctions according to claim 1, wherein the at least two confinement layers comprise at least one ion confinement layer formed by an ion implantation process. The VCSEL laser with multiple tunnel junctions according to claim 1, wherein the at least two confinement layers comprise at least one oxidation confinement layer formed by an oxidation process, and the at least two confinement layers comprise at least one oxidation confinement layer formed by ion implantation Process-formed ion confinement layer. The VCSEL laser with multiple tunnel junctions according to claim 10, wherein the at least two confinement layers are all oxidation confinement layers formed by an oxidation process. The VCSEL laser with multiple tunnel junctions of claim 13, wherein the spacing between the oxidation confinement layers is equal to 0.5*an integer multiple of the wavelength of the laser light generated by the VCSEL laser divided by the weighting of the refractive indices of the semiconductors therebetween and. A method for preparing a VCSEL laser with multiple tunnel junctions, comprising: forming an epitaxial structure through an epitaxial growth process, comprising: a substrate, a first reflector and a second reflector located above the substrate, and , a plurality of active regions and a plurality of tunnel junctions formed between the first reflector and the second reflector, the plurality of active regions and the plurality of tunnel junctions being alternately arranged; and At least a carbon dioxide confinement layer is formed between the first reflector and the second reflector through an oxidation process, and the at least carbon dioxide confinement layers respectively have openings, wherein at least part of the openings are among the openings. There are different apertures between them to take into account the photoelectric conversion efficiency and the far-field beam divergence angle. The manufacturing method of claim 15, wherein the oxidation confinement layers are formed over each of the active regions, respectively, and the number of the oxidation confinement layers is consistent with the number of the active regions. The manufacturing method of claim 15, wherein the oxidation confinement layer is selectively formed over a portion of the active regions, and the number of the oxidation confinement layers is smaller than the number of the active regions. The preparation method according to claim 15, wherein the pore diameter of the openings ranges from 1 um to 100 um. The preparation method according to claim 15, wherein the pore diameter of the openings ranges from 3um to 50um. The preparation method according to claim 19, wherein the pore diameter difference between the openings ranges from 0.1 um to 95 um. The preparation method according to claim 20, wherein the pore diameter difference between the openings ranges from 0.5um to 20um. The preparation method of claim 16, wherein the openings of the oxidation confinement layer closest to the second reflector in the at least the dioxide confinement layer have the smallest pore diameter.

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