Semiconductor laser structure and method for manufacturing the same

Abstract

The application discloses a semiconductor laser structure and a preparation method thereof. The semiconductor laser structure comprises an n-type optical confinement layer, an n-type lower optical waveguide layer, a multi-quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer and a p-type optical confinement layer arranged in sequence; the p-type optical confinement layer has a superlattice structure, one superlattice period of which comprises a first p-type doped layer and a second p-type doped layer arranged in stack; a high-doped region and a low-doped region in each p-type doped layer are arranged in sequence along a direction gradually away from an interface of the two p-type doped layers, and the high-doped region is adjacent to the interface. The application can effectively improve the working performance of the semiconductor laser, for example, greatly reduce the working voltage and significantly improve the light efficiency.

Description

Technical Field

[0001] This application relates to a semiconductor laser, and more particularly to a semiconductor laser structure based on a III-V compound and its fabrication method, belonging to the field of semiconductor technology. Background Technology

[0002] In recent years, GaN-based wide-bandgap semiconductor materials have attracted much attention due to their wide applications in light-emitting devices, photodetectors, and radiation-resistant, high-frequency, and high-power devices. P-type doping is one of the key factors limiting the performance of GaN-based optoelectronic devices. For example, current p-type AlGaN doping suffers from a high activation energy, leading to a low hole concentration in p-type AlGaN-based materials. Increasing Mg doping, due to the compensating effect of Mg, will further reduce the hole concentration and degrade crystal quality.

[0003] Researchers in this field have proposed several methods to improve the doping efficiency of p-type GaN and AlGaN, including Delta doping and superlattice structure doping. While Delta doping can modulate the band structure to some extent, its effect on band modulation through doping is limited, and its contribution to carrier enhancement is also limited. Superlattice structure doping reduces the activation energy and increases hole concentration to some extent by creating discontinuities in the interfacial band structure. However, because the valence band order changes at the upper and lower interfaces of the superlattice structure are not the same, in the

[0001] direction, the valence band at the GaN / AlGaN interface is pulled downwards due to polarization, making Mg easier to activate. Conversely, the valence band at the AlGaN / GaN interface is pulled upwards due to polarization, making Mg more difficult to activate. This difference in valence band order results in different activation efficiencies at these two interfaces. Existing methods using uniform high doping tend to increase internal defects in the material, failing to contribute to the hole concentration, thus maintaining a low overall hole concentration. This, in turn, severely impacts various aspects of the performance of GaN-based semiconductor lasers and other optoelectronic devices. Summary of the Invention

[0004] The main objective of this application is to provide a semiconductor laser structure and its fabrication method to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted in this application includes:

[0006] One aspect of this application provides a semiconductor laser structure, including an n-type optical confinement layer, an n-type lower optical waveguide layer, a multiple quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, and a p-type optical confinement layer arranged sequentially along a predetermined direction; the p-type optical confinement layer has a superlattice structure, wherein one superlattice period includes two p-type doped layers stacked together, each p-type doped layer having a first region and a second region, the first region and the second region being arranged sequentially along a direction gradually moving away from the interface between the two p-type doped layers, the first region being adjacent to the interface, and the doping concentration of the first region being higher than that of the second region.

[0007] Another aspect of this application provides a method for fabricating a semiconductor laser structure, comprising sequentially growing an n-type optical confinement layer, an n-type lower optical waveguide layer, a multiple quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, a p-type optical confinement layer, and a p-type ohmic contact layer on a substrate; wherein the p-type electron blocking layer has a superlattice structure, wherein one superlattice period includes a first p-type doped layer and a second p-type doped layer stacked together; the fabrication method specifically includes:

[0008] The second region of the first p-type doped layer, the first region of the first p-type doped layer, the first region of the second p-type doped layer, and the second region of the second p-type doped layer are grown sequentially, with each first region adjacent to the interface between the first p-type doped layer and the second p-type doped layer, and the doping concentration of each first region is higher than that of the corresponding second region, thereby forming a superlattice period of the p-type optical confinement layer.

[0009] Compared to existing technologies, this application improves the design of the p-type optical confinement layer in the semiconductor laser structure, particularly by modulating the doping concentration of the acceptor element in different regions of its superlattice structure. This results in a higher doping concentration in the region near an interface within a superlattice period compared to other regions. This increases the overall hole concentration of the p-type optical confinement layer with fewer internal defects, thereby significantly reducing the laser's operating voltage, greatly improving its luminous efficiency, and avoiding the compensation effect and crystal quality deterioration caused by increasing the overall doping concentration of the p-type optical confinement layer in existing technologies. Attached Figure Description

[0010] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only intended to teach those skilled in the art how to implement this application, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of protection of this application.

[0011] Figure 1 This is a schematic diagram of a semiconductor laser structure according to a typical embodiment of this application;

[0012] Figure 2 yes Figure 1 A schematic diagram of a superlattice period of a p-type optical confinement layer;

[0013] Figure 3 This is a schematic diagram of the structure of a GaN-based laser according to Embodiment 1 of this application;

[0014] Figure 4 yes Figure 3 A schematic diagram of the epitaxial growth of a superlattice period of a p-type optical confinement layer;

[0015] Figure 5 This is a schematic diagram of the structure of a GaN-based laser according to Embodiment 2 of this application;

[0016] Figure 6 yes Figure 5 A schematic diagram of the epitaxial growth of a superlattice period of a p-type optical confinement layer. Detailed Implementation

[0017] As mentioned earlier, taking a Mg-doped p-type GaN / AlGaN superlattice as an example, the difference in valence bands between the GaN / AlGaN and AlGaN / GaN interfaces leads to different activation efficiencies. In this case, using a uniformly high-doping scheme not only fails to improve the overall hole concentration but also increases internal defects. However, to date, no effective solution has been proposed in the industry. Therefore, this application proposes a semiconductor laser structure and its fabrication method. The technical solution of this application will be described in more detail below.

[0018] Some embodiments of this application provide a semiconductor laser structure comprising an n-type optical confinement layer, an n-type lower optical waveguide layer, a multi-quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, and a p-type optical confinement layer arranged sequentially along a predetermined direction; the p-type optical confinement layer has a superlattice structure, wherein one superlattice period includes two p-type doped layers stacked together, each p-type doped layer having a first region and a second region, the first region and the second region being arranged sequentially along a direction gradually moving away from the interface of the two p-type doped layers, the first region being adjacent to the interface, and the doping concentration of the first region being higher than that of the second region.

[0019] In one embodiment, within one superlattice period of the p-type optical confinement layer, the sum of the thicknesses of all the first regions is less than half the total thickness of the superlattice period. Therefore, the first regions can be considered to be near the interface. This structural design achieves high doping near the interface, while interface polarization generates more holes, and the remaining areas are low-doped to avoid light absorption. If the sum of the thicknesses of all the first regions exceeds the total thickness of the superlattice period, the overall doped region increases, leading to increased light absorption.

[0020] In one embodiment, within one superlattice period of the p-type optical confinement layer, the first regions of the two p-type doped layers have the same doping concentration.

[0021] In one embodiment, within one superlattice period of the p-type optical confinement layer, the doping concentration of the second regions of the two p-type doped layers is also the same. Therefore, it can be considered that the average doping concentration or the overall doping concentration of the two p-type doped layers is the same.

[0022] In one embodiment, within one superlattice period of the p-type optical confinement layer, the doping concentration of the first region of each p-type doped layer is higher than that of the second region.

[0023] In one embodiment, within a superlattice period of the p-type optical confinement layer, at least a portion of at least one region of the p-type doped layer is doped in a Delta doping manner to improve crystal quality, increase carrier mobility, and thereby further reduce voltage.

[0024] In one embodiment, the doping concentration of the first region is 1e19 to 1e21, and the doping concentration of the second region is 1e18 to 1e20. If the doping concentration is too low, the corresponding hole concentration will be low; conversely, if the doping concentration is too high, a compensation effect will occur, which will also lead to a decrease in the hole concentration.

[0025] In one embodiment, the doping element in the p-type optical confinement layer includes Mg, but is not limited thereto.

[0026] In one embodiment, the semiconductor laser structure includes a substrate, an n-type optical confinement layer, an n-type lower optical waveguide layer, a multi-quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, a p-type optical confinement layer, and a p-type ohmic contact layer arranged sequentially along a predetermined direction.

[0027] In one embodiment, the semiconductor laser structure is based on group III-V compounds, particularly group III nitrides, such as binary, ternary, and multi-component compounds formed from group III elements like B, Al, Ga, In, and Ti, and group V elements like N, P, As, Sb, and Bi. Specifically, the n-type optical confinement layer, n-type lower optical waveguide layer, multi-quantum-well active region, p-type upper optical waveguide layer, p-type electron blocking layer, p-type optical confinement layer, and p-type ohmic contact layer can all be formed using group III nitrides.

[0028] For example, the p-type optical confinement layer has an AlGaN / GaN superlattice structure, and one of the two p-type doped layers is a p-type AlGaN layer and the other is a p-type GaN layer.

[0029] For example, the n-type optical confinement layer includes, but is not limited to, an AlGaN / GaN superlattice structure.

[0030] For example, the materials of the n-type lower optical waveguide layer and the p-type upper optical waveguide layer include GaN or InGaN, but are not limited thereto. Preferably, the In content in the InGaN is 1 at.% to 10 at.%.

[0031] For example, the multi-quantum-well active region includes a GaN / InGaN multi-quantum-well structure or an AlGaN / GaN multi-quantum-well structure, but is not limited thereto.

[0032] For example, the material of the p-type electron blocking layer includes AlGaN, but is not limited thereto.

[0033] For example, the material of the p-type ohmic contact layer includes InGaN, but is not limited to this.

[0034] For example, the substrate may include a self-supporting GaN substrate or a SiC substrate, but is not limited thereto.

[0035] Some embodiments of this application provide a method for fabricating the semiconductor laser structure, comprising sequentially growing an n-type optical confinement layer, an n-type lower optical waveguide layer, a multiple quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, a p-type optical confinement layer, and a p-type ohmic contact layer on a substrate; wherein the p-type electron blocking layer has a superlattice structure, wherein one superlattice period includes a first p-type doped layer and a second p-type doped layer stacked together.

[0036] Furthermore, the preparation method specifically includes:

[0037] The second region of the first p-type doped layer, the first region of the first p-type doped layer, the first region of the second p-type doped layer, and the second region of the second p-type doped layer are grown sequentially, with each first region adjacent to the interface between the first p-type doped layer and the second p-type doped layer, and the doping concentration of each first region is higher than that of the corresponding second region, thereby forming a superlattice period of the p-type optical confinement layer.

[0038] In one embodiment, the preparation method specifically includes: using delta doping to dopant elements when growing at least a portion of the first p-type doped layer and / or the second p-type doped layer.

[0039] In the method for fabricating the semiconductor laser structure of this application, structural layers such as n-type optical confinement layer, n-type lower optical waveguide layer, multi-quantum well active region, p-type upper optical waveguide layer, p-type electron blocking layer, p-type optical confinement layer and p-type ohmic contact layer can be grown by means of HVPE (hydride vapor phase epitaxy), MOCVD (metal-organic chemical vapor deposition), PECVD (plasma-enhanced chemical vapor deposition).

[0040] Please see Figure 1 In one exemplary embodiment of this application, a semiconductor laser structure includes an n-type optical confinement layer 2, an n-type lower optical waveguide layer 3, a multiple quantum well active region 4, a p-type upper optical waveguide layer 5, a p-type electron blocking layer 6, a p-type optical confinement layer 7, and a p-type ohmic contact layer 8 sequentially grown on a substrate 1. The p-type electron blocking layer 7 has an AlGaN / GaN superlattice structure and includes multiple alternating first p-type doped layers 710 and multiple second p-type doped layers 720, wherein the first p-type doped layers are GaN layers and the second p-type doped layers are AlGaN layers.

[0041] Please continue reading. Figure 2Within one superlattice period of the p-type electron blocking layer 7, the first p-type doped layer 710 has a first region 711 and a second region 712, and the second p-type doped layer 720 has a first region 721 and a second region 722. Both the first region 711 and the first region 721 of the first p-type doped layer are located near the GaN / AlGaN interface 730 (hereinafter referred to as the "interface"). In this embodiment, "near the interface" refers to a region with a thickness of h on both sides of the GaN / AlGaN interface, where h < H / 2, and H is the total thickness of one superlattice period. That is, within one superlattice period, the sum of the thicknesses of the first region 711 and the first region 721 of the first p-type doped layer is less than half the total thickness of one superlattice period. Simultaneously, it can be considered that the second regions 712 and 722 of the first p-type doped layer are distributed near the AlGaN / GaN interface.

[0042] Furthermore, for either the first p-type doped layer 710 or the second p-type doped layer 720, the average doping concentration of the first region is higher than that of the second region. For example, the doping concentration of the first region can be 1e19 to 1e21, and the doping concentration of the second region can be 1e18 to 1e20.

[0043] In yet another exemplary embodiment of this application, a semiconductor laser structure may also be referenced. Figure 1 However, within one superlattice period of the p-type optical confinement layer, both the first and second p-type doped layers have regions where Mg and other elements are doped using Delta doping.

[0044] In the semiconductor laser structure and fabrication method provided in this application, by adjusting the distribution of doped elements in the superlattice structure of the p-type optical confinement layer, the doping concentration in the region near an interface within a superlattice period is higher than that in other regions, rather than increasing the overall doping concentration. This not only reduces the internal defect density of the p-type optical confinement layer but also significantly increases its overall hole concentration, avoiding compensation effects and crystal quality deterioration. Consequently, the working performance of the semiconductor laser is greatly improved, including but not limited to reducing its operating voltage and improving its optical efficiency.

[0045] The technical solutions of this application will be explained in more detail below with reference to several embodiments. However, these specific descriptions are only for teaching those skilled in the art how to implement this application, and are not intended to exhaust all feasible methods of this application, nor to limit the scope of this application.

[0046] Example 1

[0047] Please see Figure 3 The gallium nitride-based semiconductor laser structure provided in this embodiment includes a gallium nitride substrate 1 and an n-type AlGaN optical confinement layer 2, an n-type InGaN lower optical waveguide layer 3, an InGaN / GaN multi-quantum well active region 4, an InGaN upper optical waveguide layer 5, a p-type AlGaN electron blocking layer 6, a p-type optical confinement layer 7, and a p-type GaN contact layer 8 sequentially grown on the gallium nitride substrate 1.

[0048] The thickness of the gallium nitride substrate 1 is approximately 300 μm. The thickness of the n-type optical confinement layer 2 is approximately 1 μm, with Si as the donor impurity and an Al content of approximately 10 at.%. The thickness of the n-type InGaN under-optical waveguide layer 3 is approximately 300 nm, with an In content of approximately 6 at.%, using Si as the donor impurity and a doping concentration of approximately 1e17 cm⁻¹. -3 In the InGaN / GaN multi-quantum-well active region 4, the thickness of the quantum wells is approximately 3 nm, and the thickness of the quantum barriers is approximately 6 nm. In the InGaN optical waveguide layer 5, the In composition content is approximately 3 at.%, and the thickness is approximately 300 nm. The p-type AlGaN electron blocking layer 6 has a thickness of approximately 20 nm, an Al composition content of approximately 20 at.%, and uses Mg as its acceptor impurity with a concentration of approximately 2e19 cm⁻¹. -3 .

[0049] Furthermore, the p-type optical confinement layer 7 has a superlattice structure containing 60 superlattice periods. Each superlattice period includes a p-type GaN low-doped region 7-1, a p-type GaN high-doped region 7-2, a p-type AlGaN high-doped region 7-3, and a p-type AlGaN low-doped region 7-4. The thickness of each doped region is approximately 1.25 nm, and the total thickness of one superlattice period is approximately 5 nm. The average doping concentration of the p-type GaN low-doped region 7-1 and the p-type AlGaN low-doped region 7-4 is approximately 6e18, and the average doping concentration of the p-type GaN high-doped region 7-2 and the p-type AlGaN high-doped region 7-3 is approximately 2e19.

[0050] This gallium nitride-based semiconductor laser structure can be fabricated using MOCVD according to process conditions well known to those skilled in the art. The growth process of one superlattice period of the p-type optical confinement layer 7 can be found in [reference needed]. Figure 4 .

[0051] Comparative Example 1

[0052] The gallium nitride-based semiconductor laser structure provided in this comparative example is basically the same as that in Example 1, except that the Mg element in each superlattice period of the p-type optical confinement layer is uniformly distributed in the GaN layer and AlGaN layer, with a doping concentration of about 2e19.

[0053] Example 2

[0054] Please see Figure 5 The gallium nitride-based semiconductor laser structure provided in this embodiment includes a gallium nitride substrate 1 and an n-type AlGaN optical confinement layer 2, an n-type InGaN lower optical waveguide layer 3, an InGaN / GaN multi-quantum well active region 4, an InGaN upper optical waveguide layer 5, a p-type AlGaN electron blocking layer 6, a p-type optical confinement layer 7', and a p-type GaN contact layer 8 sequentially grown on the gallium nitride substrate 1.

[0055] The thickness of the gallium nitride substrate 1 is approximately 300 μm. The thickness of the n-type optical confinement layer 2 is approximately 1 μm, with Si as the donor impurity and an Al content of approximately 10 at.%. The thickness of the n-type InGaN under-optical waveguide layer 3 is approximately 300 nm, with an In content of approximately 6 at.%, using Si as the donor impurity and a doping concentration of approximately 1e17 cm⁻¹. -3 In the InGaN / GaN multi-quantum-well active region 4, the thickness of the quantum wells is approximately 3 nm, and the thickness of the quantum barriers is approximately 6 nm. In the InGaN optical waveguide layer 5, the In composition content is approximately 3 at.%, and the thickness is approximately 300 nm. The p-type AlGaN electron blocking layer 6 has a thickness of approximately 20 nm, an Al composition content of approximately 20 at.%, and uses Mg as its acceptor impurity with a concentration of approximately 2e19 cm⁻¹. -3 .

[0056] Furthermore, the p-type optical confinement layer 7' has a superlattice structure containing 60 superlattice periods, one of which includes a p-type GaN low-doped region 7-1', a p-type GaN Delta-doped region 7-2', a p-type AlGaN Delta-doped region 7-3', and a p-type AlGaN low-doped region 7-4'. The p-type GaN low-doped region 7-1' has a thickness of approximately 2 nm and a doping concentration of 8e18; the p-type GaN Delta-doped region 7-2' has a thickness of approximately 0.5 nm and a doping concentration of approximately 1.5e19; the p-type AlGaN Delta-doped region 7-3' has a thickness of approximately 0.5 nm and a doping concentration of approximately 1.5e19; and the p-type AlGaN low-doped region 7-4' has a thickness of approximately 2 nm and a doping concentration of approximately 8e18. The total thickness of this p-type optical confinement layer 7' is approximately 300 nm.

[0057] This gallium nitride-based semiconductor laser structure can also be fabricated using epitaxial growth processes well known to those skilled in the art.

[0058] The growth process of one superlattice period of the p-type optical confinement layer 7' can be found in [reference needed]. Figure 6 .

[0059] The EL voltage and other parameters of the laser structures obtained in Examples 1, 2 and Comparative Example 1 were tested, and the results are shown in Table 1 below.

[0060] Table 1. EL voltage test results of laser structures in Examples 1 and 2 and Comparative Example 1.

[0061] Example 1 Voltage (V) 3.48 6.30 Example 2 Voltage (V) 3.35 6.21 Comparative Example 1 Voltage (V) 3.76 6.76

[0062] Although this application has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of this application, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of this application to adapt particular situations or materials to the teachings of this application. Therefore, this application is not intended to be limited to the specific embodiments disclosed for carrying out this application, but rather is intended to include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A semiconductor laser structure, comprising an n-type optical confinement layer, an n-type lower optical waveguide layer, a multi-quantum-well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, and a p-type optical confinement layer sequentially arranged along a predetermined direction; characterized in that: The p-type optical confinement layer has an AlGaN / GaN superlattice structure, wherein one superlattice period includes two stacked p-type doped layers; one of the two p-type doped layers is a p-type AlGaN layer and the other is a p-type GaN layer; each p-type doped layer has a first region and a second region, the first region and the second region are arranged sequentially along a direction gradually away from the interface between the two p-type doped layers, the first region is adjacent to the interface, and the doping concentration of the first region is higher than that of the second region. Furthermore, within one superlattice period of the p-type optical confinement layer, the sum of the thicknesses of all the first regions is less than half the total thickness of the superlattice period, the first regions of the two p-type doped layers have the same doping concentration, and the second regions of the two p-type doped layers have the same doping concentration.

2. The semiconductor laser structure according to claim 1, characterized in that: The doping concentration of the first region is 1e19~1e21, and the doping concentration of the second region is 1e18~1e20.

3. The semiconductor laser structure according to claim 1, characterized in that: The doping element in the p-type optical confinement layer includes Mg.

4. The semiconductor laser structure according to claim 1, characterized in that: The semiconductor laser structure includes a substrate, an n-type optical confinement layer, an n-type lower optical waveguide layer, a multi-quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, a p-type optical confinement layer, and a p-type ohmic contact layer arranged sequentially along a set direction.

5. The semiconductor laser structure according to claim 4, characterized in that, The substrate includes a self-supporting GaN substrate or a SiC substrate.

6. The semiconductor laser structure according to claim 4, characterized in that: The n-type lower optical waveguide layer and the p-type upper optical waveguide layer are made of InGaN, with an In content of 1 at.% to 10 at.%.

7. The semiconductor laser structure according to claim 4, characterized in that: The n-type optical confinement layer comprises an AlGaN / GaN superlattice structure.

8. The semiconductor laser structure according to claim 4, characterized in that: The materials of the n-type lower optical waveguide layer and the p-type upper optical waveguide layer include GaN or InGaN.

9. The semiconductor laser structure according to claim 4, characterized in that: The active region of the multiple quantum wells includes a GaN / InGaN multiple quantum well structure or an AlGaN / GaN multiple quantum well structure.

10. The semiconductor laser structure according to claim 4, characterized in that: The p-type electron blocking layer is made of AlGaN.

11. The semiconductor laser structure according to claim 4, characterized in that: The material of the p-type ohmic contact layer includes InGaN.

12. A method for fabricating a semiconductor laser structure, comprising sequentially growing an n-type optical confinement layer, an n-type lower optical waveguide layer, a multiple quantum well active region, a p-type upper optical waveguide layer, a p-type electron blocking layer, a p-type optical confinement layer, and a p-type ohmic contact layer on a substrate; wherein the p-type optical confinement layer has a superlattice structure, wherein one superlattice period includes a first p-type doped layer and a second p-type doped layer stacked together, wherein one of the first p-type doped layer and the second p-type doped layer is a p-type AlGaN layer, and the other is a p-type GaN layer; characterized in that, The preparation method specifically includes: The second region of the first p-type doped layer, the first region of the first p-type doped layer, the first region of the second p-type doped layer, and the second region of the second p-type doped layer are grown sequentially, with each first region adjacent to the interface between the first p-type doped layer and the second p-type doped layer, and the doping concentration of each first region is higher than that of the corresponding second region, thereby forming a superlattice period of the p-type optical confinement layer. Furthermore, within one superlattice period of the p-type optical confinement layer, the sum of the thicknesses of all the first regions is less than half the total thickness of the superlattice period, the first regions of the two p-type doped layers have the same doping concentration, and the second regions of the two p-type doped layers have the same doping concentration.

13. The method for fabricating a semiconductor laser structure according to claim 12, characterized in that: The doping concentration of the first region is 1e19~1e21, and the doping concentration of the second region is 1e18~1e20.

14. The method for fabricating a semiconductor laser structure according to claim 12, characterized in that: Within one superlattice period of the p-type optical confinement layer, at least a portion of the p-type doped layer is doped in a Delta doping manner.

15. The method for fabricating a semiconductor laser structure according to any one of claims 12-14, characterized in that: The doping element in the p-type optical confinement layer includes Mg.

16. The method for fabricating a semiconductor laser structure according to any one of claims 12-14, characterized in that: The n-type optical confinement layer comprises an AlGaN / GaN superlattice structure.

17. The method for fabricating a semiconductor laser structure according to any one of claims 12-14, characterized in that: The materials of the n-type lower optical waveguide layer and the p-type upper optical waveguide layer include GaN or InGaN, and the In component content in InGaN is 1 at.% to 10 at.%.

18. The method for fabricating a semiconductor laser structure according to any one of claims 12-14, characterized in that: The active region of the multiple quantum wells includes a GaN / InGaN multiple quantum well structure or an AlGaN / GaN multiple quantum well structure.

19. The method for fabricating a semiconductor laser structure according to any one of claims 12-14, characterized in that: The p-type electron blocking layer is made of AlGaN.

20. The method for fabricating a semiconductor laser structure according to any one of claims 12-14, characterized in that: The material of the p-type ohmic contact layer includes InGaN.

21. The method for fabricating a semiconductor laser structure according to any one of claims 12-14, characterized in that: The substrate includes a self-supporting GaN substrate or a SiC substrate.

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