980nm high-power semiconductor laser epitaxial wafer and preparation method thereof

Abstract

The present application relates to the field of optoelectronic technology, and in particular to a 980nm high-power semiconductor laser epitaxial wafer and a preparation method thereof. The epitaxial wafer comprises, from bottom to top along the growth direction, a GaAs substrate, a GaAs buffer layer, an N-side confinement layer, a first N-side graded-composition waveguide layer, a second N-side graded-composition waveguide layer, an N-side barrier layer, a quantum well, a P-side barrier layer, a P-side graded-composition waveguide layer, a P-side constant-composition waveguide layer, a P-side confinement layer and a GaAs ohmic contact layer. The present application widens the optical field to the N side through an asymmetric graded waveguide, reduces the cavity surface light power density and makes the heat evenly distributed; introduces tensile strain through a P-containing segmented strain waveguide, increases the band gap, reduces intrinsic absorption and free carrier absorption, enhances carrier confinement, suppresses non-radiative recombination and realizes strain compensation; optimizes the doping distribution to reduce heat generation. The COMD risk is reduced from the source, and the device reliability is improved.

Description

Technical Field

[0001] This invention relates to the field of optoelectronics technology, specifically to a 980nm high-power semiconductor laser epitaxial wafer and its fabrication method. Background Technology

[0002] Driven by strong demand from various fields such as industrial processing, consumer electronics, medical devices, and scientific research, the application scale of semiconductor lasers has experienced explosive growth in recent years. Among them, high-power semiconductor lasers based on gallium arsenide (GaAs) materials have become one of the most mature technologies on the market due to their excellent electro-optical conversion efficiency, extremely high output power, and record-breaking brightness. However, the most fundamental problem limiting the output power and reliability of this type of laser remains catastrophic optical cavity surface damage (COMD) at the output cavity surface. COMD not only causes instantaneous failure of laser performance but also directly affects the overall system performance of fiber lasers and solid-state lasers pumped by them. Therefore, this problem has been extensively studied.

[0003] To suppress COD and improve device reliability, current technologies mainly focus on chip fabrication, such as using cavity surface passivation, near-cavity surface current non-injection, and optimizing heat sink structures. Regarding epitaxial structure optimization, a few researchers have attempted to control the optical field distribution through waveguide layer design. For example, the paper *Journal of Applied Physics*, 132, 012104 (2023) proposes an asymmetric waveguide structure design that broadens the optical field to the confinement layer, reducing the power density in the active region. However, this also lowers the confinement factor, resulting in poor static electrical parameters, making practical applications of this design difficult. The paper *IEEE Journal of Quantum Electronics*, 18(7): 1416–1420 (2024) reports a large-cavity, wide-waveguide structure with high COD performance, but the thicker waveguide design increases the number of optical field modes, leading to lower output power and potential mode competition in practical applications. More importantly, existing epitaxial structures lack precise control over the stress in the active region and fail to organically combine compositional gradients with tensile strain compensation. This results in high interband absorption near the active region, severe nonradiative recombination of free carriers, and prominent cavity surface heat accumulation problems, making it impossible to fundamentally solve the COMD failure problem. Summary of the Invention

[0004] To address the technical problems of existing GaAs-based 980nm high-power semiconductor lasers, such as catastrophic optical cavity surface damage, excessively high cavity surface power density, severe heat accumulation, and high optical absorption loss, this invention provides a high-reliability epitaxial wafer for a 980nm high-power semiconductor laser. This epitaxial wafer employs an N-side double-layer graded-component waveguide and a P-side graded-component waveguide. The co-design of constant composition waveguide and piecewise strained waveguide broadens the optical field through asymmetric gradient and achieves stress compensation and low absorption loss through piecewise strain. Combined with gradient doping to optimize carrier transport, it reduces the risk of thermal damage to the cavity surface from the source, significantly improves the COD threshold and overall optoelectronic performance, and solves the defects of poor electrical parameters, low output power and insufficient reliability of existing structures.

[0005] The technical solution of this invention is as follows: In a first aspect, the present invention provides a 980nm high-power semiconductor laser epitaxial wafer, wherein the epitaxial wafer comprises, from bottom to top along the growth direction: a GaAs substrate, a GaAs buffer layer, an N-side confinement layer, a first N-side graded composition waveguide layer, a second N-side graded composition waveguide layer, an N-side barrier layer, a quantum well, a P-side barrier layer, a P-side graded composition waveguide layer, a P-side constant composition waveguide layer, a P-side confinement layer, and a GaAs ohmic contact layer. The first N-side graded-component waveguide layer is Al x2 Ga 1-x2 As, where 0.15≤x2≤0.4, x2 changes linearly in the range of 0.15~0.4, gradually changing from a high value to a low value; The second N-side graded-component waveguide layer is Al x3 Ga 1-x3 As 1-z1 P z1 Where 0.12≤x3≤0.25, 0.01≤z1≤0.04, and x3 gradually changes linearly within the range of 0.12 to 0.25, from high value to low value; The P-side graded component waveguide layer is Al. x4 Ga 1-x4 As 1-z2 P z2 Where 0.12≤x4≤0.18, 0.01≤z2≤0.04, and x4 gradually changes linearly within the range of 0.12 to 0.18, from low to high values; The P-side constant composition waveguide layer is Al. x5 Ga 1-x5 As, where 0.14≤x5≤0.18.

[0006] Furthermore, the first N-side graded-component waveguide layer Al x2 Ga 1-x2 In As, x2 linearly varies from 0.3 to 0.18; the second N-side graded-component waveguide layer Al x3 Ga 1-x3 As 1-z1 P z1 In the middle, x3 linearly decreases from 0.18 to 0.14; the P-side graded component waveguide layer Al x4 Ga1-x4 As 1-z2 P z2 In the middle, x4 gradually changes linearly from 0.14 to 0.16.

[0007] Furthermore, the first N-side graded-component waveguide layer Al x2 Ga 1-x2 The thickness of the As layer is 0.3~0.5μm, and the doping method is graded doping with a doping concentration of 8×10⁻⁶. 16 ~2×10 17 atoms / cm³; the second N-side graded-component waveguide layer Al x3 Ga 1-x3 As 1-z1 P z1 The thickness is 0.1~0.4μm, and it is not intentionally doped.

[0008] Furthermore, the first N-side graded-component waveguide layer Al x2 Ga 1-x2 The thickness of As is 0.4 μm; The second N-side graded composition waveguide layer Al x3 Ga 1-x3 As 1-z1 P z1 The thickness is 0.25 μm; P-side graded component waveguide layer Al x4 Ga 1-x4 As 1-z2 P z2 The thickness is 0.1~0.2μm, and it is not intentionally doped; P-side constant composition waveguide layer Al x5 Ga 1-x5 The thickness of As is 0.1~0.3μm, and the doping concentration is 6×10⁻⁶. 17 ~2×10 18 atoms / cm³.

[0009] Furthermore, the P-side graded component waveguide layer Al x4 Ga 1-x4 As 1-z2 P z2 The thickness is 0.15 μm; the P-side constant composition waveguide layer Al x5 Ga 1-x5 The thickness of the As layer is 0.12 μm, and the doping source is CBr4 with a doping concentration of 9 × 10⁻⁶. 17 atoms / cm³.

[0010] Furthermore, the GaAs buffer layer has a thickness of 300~350nm and a doping concentration of 2×10⁻⁶. 18 ~5×10 18atoms / cm³; The N-side confinement layer is Al. x1 Ga 1-x1 As, with a thickness of 1.2~1.6μm and a doping concentration of 1.5×10⁻⁶. 18 ~2.5×10 18 atoms / cm³; The N-side barrier layer is GaAs. y1 P 1-y1 The thickness is 10~20nm, and it is not intentionally doped; The quantum well is In y2 Ga 1-y2 As, with a thickness of 5~10nm, is not intentionally doped; The P-side barrier layer is Ga. x As y3 P 1-y3 The thickness is 10~20nm, and it is not intentionally doped; The P-side confinement layer is A. lx6 Ga 1-x6 As, with a thickness of 0.3~0.5μm and a doping concentration of 1×10⁻⁶. 18 ~2×10 18 atoms / cm³; The thickness of the GaAs ohmic contact layer is 500~700 nm, and the doping concentration is 2.5×10⁻⁶. 19 ~4.5×10 19 atoms / cm³.

[0011] Furthermore, the GaAs buffer layer has a thickness of 320 nm and a doping concentration of 4 × 10⁻⁶. 18 atoms / cm³; The N-side confinement layer Al x1 Ga 1-x1 The thickness of the As layer is 1.4 μm, and the doping concentration is 2 × 10⁻⁶. 18 atoms / cm³; The N-side barrier layer is GaAs. y1 P 1-y1 The thickness is 17nm, and it is not intentionally doped; The quantum well In y2 Ga 1-y2 The thickness of As is 8.5 nm, which is not intentionally doped; The P-side barrier layer GaAs y3 P 1-y3 The thickness is 17nm, and it is not intentionally doped; The P-side confinement layer Al x6 Ga 1-x6 The thickness of the As layer is 0.4 μm, and the doping concentration is 1.5 × 10⁻⁶.18 atoms / cm³; The GaAs ohmic contact layer has a thickness of 600 nm and a doping concentration of 3.5 × 10⁻⁶. 19 atoms / cm³.

[0012] Furthermore, the N-side confinement layer Al x1 Ga 1-x1 The doping source for As is Si2H6; the P-side confinement layer Al x6 Ga 1-x6 The doping source for As is CBr4; the doping source for the GaAs ohmic contact layer is CBr4.

[0013] Secondly, the present invention provides a method for fabricating a 980nm high-power semiconductor laser epitaxial wafer, the method comprising the following steps: S1. Place the GaAs substrate in the MOCVD reaction chamber, heat the H2 environment to 500-550℃, then introduce AsH3, and heat the temperature to 790-830℃ for 40-50 minutes. S2. The temperature is reduced to 670-690℃, and the cooling rate is no higher than 40℃ / min. MO source TMGa and AsH3 are introduced to grow a GaAs buffer layer on the GaAs substrate. S3. Increase the temperature to 730-750℃, with a heating rate not exceeding 50℃ / min, and introduce TMAl, TMGa, and AsH3 to grow an N-side confinement layer Al on the GaAs buffer layer. x1 Ga 1-x1 As; S4. Maintain the temperature at 730-750℃, introduce TMAl, TMGa, and AH3, and confine the Al layer on the N-side. x1 Ga 1-x1 A first N-side graded-component waveguide layer Al is grown on As. x2 Ga 1-x2 As; S5. Maintain the temperature at 730-750℃, introduce TMAl, TMGa, and AH3, PH3, and apply Al to the graded waveguide layer on the first N-side. x2 Ga 1-x2 A second N-side graded-component waveguide layer Al is grown on As. x3 Ga 1--x3 As 1-z1 P z1 ; S6. Temperature is reduced to 670-690℃, with a cooling rate not exceeding 40℃ / min. TMGa, AsH3, and PH3 are introduced, and the Al phased-component waveguide layer on the second N-side is... x3 Ga 1--x3 As 1-z1P z1 On-grown N-side barrier layer GaAs y1 P 1-y1 ; S7. Maintain the temperature at 670-690℃, introduce TMGa, TMIn, and AsH3, and then introduce GaAs on the N-side barrier layer. y1 P 1-y1 On-grown quantum well In y2 Ga 1-y2 As; S8, with the temperature maintained at 670-690℃, TMGa, PH3, and AsH3 are introduced into the quantum well In. y2 Ga 1-y2 GaAs with P-barrier layer grown on As y3 P 1-y3 ; S9. Raise the temperature to 730-750℃, with a heating rate not exceeding 50℃ / min, and introduce TMAl, TMGa, and AH3 into the GaAs barrier layer on the p-side. y3 P 1-y3 On-grown P-side graded composition waveguide layer Al x4 Ga 1-x4 As 1-z2 P z2 ; S10, with the temperature maintained at 730-750℃, introduces TMAl, TMGa, and AsH3, and performs graded composition waveguide layer Al on the P-side. x4 Ga 1-x4 As 1-z2 P z2 On-grown P-side constant composition waveguide layer Al x5 Ga 1-x5 As; S11. The temperature is raised to 790-810℃, with a heating rate not exceeding 50℃ / min. TMAl, TMGa, and AsH3 are introduced, and the Al waveguide layer on the P side is kept constant in composition. x5 Ga 1-x5 As grows a P-side confinement layer Al x6 Ga 1-x6 As; S12, the temperature is reduced to 540-560℃, TMGa and AsH3 are introduced, and Al is used as the confinement layer on the P side. x6 Ga 1-x6 A GaAs ohmic contact layer is grown on As.

[0014] The beneficial effects of this invention are as follows: This invention optimizes the optical field distribution and reduces the cavity surface optical power density through waveguide structure design. Simultaneously, it uses segmented strain waveguides to reduce light absorption near the active region, thereby increasing the overall COD performance of the structure. The structure employs an asymmetric waveguide to move the optical field away from the active region, reducing the cavity surface optical power density and indirectly improving the stability of the cavity surface material. Increasing the waveguide layer thickness while using a gradient composition design broadens the optical field, allowing for more uniform heat distribution over a larger area. Furthermore, the segmented strain waveguide design achieves strain compensation for the entire structure, regulating the stress distribution. The increased strain waveguide widens the material's bandgap, making it more difficult for photons to excite electron transitions, significantly reducing intrinsic interband absorption. Simultaneously, it enhances carrier confinement, reducing free carrier absorption and defect-nonradiative recombination, suppressing nonradiative recombination centers, reducing defect-related absorption losses, and increasing the transparency window range. This reduces heat generation at the source, preventing COD caused by heat accumulation at the cavity surface. Finally, by optimizing the doping distribution, the reliability of the device is improved without affecting structural performance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the semiconductor laser epitaxial wafer prepared according to the present invention.

[0017] Figure 2 This is a schematic diagram of the structure of the semiconductor laser epitaxial wafer of Comparative Example 1 of the present invention.

[0018] In the figure, there is a 101-GaAs substrate, a 102-GaAs buffer layer, and a 103-N-side confinement layer (Al). x1 Ga 1-x1 As, 104 - First N-side graded-component waveguide layer Al x2 Ga 1-x2 As, 105-Second N-side graded-component waveguide layer Al x3 Ga 1-x3 As 1-z1 P z1 106-N side barrier layer GaAs y1 P 1-y1 ,107-quantum wellIn y2 Ga 1-y2 As, 108-P side barrier layer Ga x As y3 P 1-y3 109-P side graded composition waveguide layer Al x4Ga 1-x4 As 1-z2 P z2 110-P side constant composition waveguide layer Al x5 Ga 1-x5 As, 111-P side confinement layer A lx6 Ga 1-x6 As, 112-GaAs ohmic contact layer.

[0019] The structure consists of a 2-1-GaAs substrate, a 2-2-GaAs buffer layer, a 2-3-N-side confinement layer, a 2-4-N-side waveguide layer, a 2-5-N-side barrier layer, a 2-6-quantum well, a 2-7-P-side barrier layer, a 2-8-P-side waveguide layer, a 2-9-P-side confinement layer, and a 2-10-GaAs ohmic contact layer. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0021] Example 1 like Figure 1 As shown, a 980nm high-power semiconductor laser epitaxial wafer, the epitaxial wafer consisting of, from bottom to top along the growth direction: GaAs substrate 101, GaAs buffer layer 102, and N-side confinement layer Al x1 Ga 1-x1 As 103, the first N-side graded-ratio waveguide layer is Al x2 Ga 1-x2 As 104, the second N-side graded-component waveguide layer is Al x3 Ga 1-x3 As 1-z1 P z1 105, N-side barrier layer GaAs y1 P 1- y1 106. Quantum well In y2 Ga 1-y2 As 107, P-side barrier layer Ga x As y3 P 1-y3 108. P-side graded-component waveguide layer Al x4 Ga 1-x4 As 1- z2 P z2109. P-side constant composition waveguide layer Al x5 Ga 1-x5 As 110, P-side confinement layer A lx6 Ga 1-x6 As 111 and GaAs ohmic contact layer 112.

[0022] A method for fabricating the epitaxial wafer of the aforementioned 980nm high-power semiconductor laser. S1. Place the GaAs substrate 101 in the MOCVD reaction chamber, heat the H2 environment to 520°C, then introduce AsH3, raise the temperature to 810°C and perform heat treatment for 45 minutes. S2. Temperature is reduced to 680℃ at a rate of 40℃ / min. TMGa and AsH3 are introduced to grow a GaAs buffer layer 102 with a thickness of 320nm and a doping concentration of 4×10⁻⁶. 18 Atoms / cm³, with Si2H6 as the N-type doping source; S3. The temperature is increased to 740℃ at a rate of 50℃ / min, and TMAl, TMGa, and AsH3 are introduced to grow the N-side confinement layer Al. x1 Ga 1-x1 As 103, thickness 1.4 μm, doping concentration 2 × 10⁻⁶ 18 One atom / cm³, with Si2H6 as the doping source.

[0023] S4. Maintain the temperature at 740℃, introduce TMAl, TMGa, and AsH3 to grow the first N-side graded-component waveguide layer Al. x2 Ga 1-x2 As 104, 0.4 μm thick, x2 linearly gradient from 0.3 to 0.18, doping using gradient doping, doping range from 8 × 10⁻⁶ 16 Gradient to 2×10 16 atoms / cm³.

[0024] S5. Maintain the temperature at 740℃, introduce TMAl, TMGa, AsH3, and PH3 to grow the second N-side graded-component waveguide layer Alx3Ga. 1-x3 As 1-Z1 P Z1 105, thickness 0.25μm, x3 linearly gradient from 0.18 to 0.14, unintentional doping.

[0025] S6. Temperature is reduced to 680℃ at a rate of 40℃ / min. TMGa, AsH3, and PH3 are introduced to grow the N-side barrier layer GaAs. y1 P 1-y1 106, thickness 17nm, unintentional doping.

[0026] S7. Maintain the temperature at 680℃, introduce TMGa, TMIn, and AsH3 to grow a quantum well In. y2 Ga 1-y2 As 107, 8.5 nm thick, unintentionally doped.

[0027] S8. Maintain the temperature at 680℃, introduce TMGa, PH3, and AsH3 to grow the P-side barrier layer Ga. x As y3 P 1-y3 108, thickness 17nm, unintentional doping.

[0028] S9. Temperature is increased to 740℃ at a rate of 50℃ / min. TMAl, TMGa, AsH3, and PH3 are introduced to grow a P-side graded composition waveguide layer (Al). x4 Ga 1-x4 As 1-z2 P z2 109, thickness 0.15μm, x4 linearly gradient from 0.14 to 0.16, z2=0.025, unintentional doping.

[0029] S10, temperature maintained at 740℃, TMAl, TMGa and AsH3 introduced, constant composition waveguide layer Al on P side. x5 Ga 1-x5 As110, thickness 0.12 μm, doping concentration 9 × 10⁻⁶ 17 Atoms / cm³, with CBr4 as the P-type doping source.

[0030] S11. Increase the temperature to 800℃ at a rate of 50℃ / min, introduce TMAl, TMGa, and AsH3, and grow the P-side confinement layer A. lx6 Ga 1-x6 As 111, thickness 0.4 μm, doping concentration 1.5 × 10⁻⁶ 18 Atoms / cm³, with CBr4 as the P-type doping source.

[0031] S12, the temperature is reduced to 550℃, TMGa and AsH3 are introduced to grow a GaAs ohmic contact layer 112 with a thickness of 600nm and a doping concentration of 3.5×10⁻⁶. 19 Atoms / cm³, with CBr4 as the P-type doping source.

[0032] Example 2 A method for fabricating the epitaxial wafer of the aforementioned 980nm high-power semiconductor laser. S1. Place the GaAs substrate 101 in the MOCVD reaction chamber, heat the H2 environment to 520°C, then introduce AsH3, raise the temperature to 810°C and perform heat treatment for 45 minutes. S2. Temperature is reduced to 680℃ at a rate of 40℃ / min. TMGa and AsH3 are introduced to grow a GaAs buffer layer 102 with a thickness of 300nm and a doping concentration of 2×10⁻⁶. 18 Atoms / cm³, with Si2H6 as the N-type doping source; S3. The temperature is increased to 740℃ at a rate of 50℃ / min, and TMAl, TMGa, and AsH3 are introduced to grow the N-side confinement layer Al. x1 Ga 1-x1 As 103, thickness 1.2 μm, doping concentration 1.5 × 10⁻⁶ 18 One atom / cm³, with Si2H6 as the doping source.

[0033] S4. Maintain the temperature at 740℃, introduce TMAl, TMGa, and AsH3 to grow the first N-side graded-component waveguide layer Al. x2 Ga 1-x2 As 104, 0.3 μm thick, x2 linearly gradient from 0.35 to 0.20, doping using gradient doping, doping range from 8 × 10 16 Gradient to 2×10 16 atoms / cm³.

[0034] S5. Maintain the temperature at 740℃, introduce TMAl, TMGa, AsH3, and PH3 to grow the second N-side graded-component waveguide layer Alx3Ga. 1-x3 As 1-z1 P z1 105, thickness 0.1μm, x3 linearly gradient from 0.18 to 0.16, unintentional doping.

[0035] S6. Temperature is reduced to 680℃ at a rate of 40℃ / min. TMGa, AsH3, and PH3 are introduced to grow the N-side barrier layer GaAs. y1 P 1-y1 106, thickness 10nm, unintentional doping.

[0036] S7. Maintain the temperature at 680℃, introduce TMGa, TMIn, and AsH3 to grow a quantum well In. y2 Ga 1-y2 As 107, 5nm thick, unintentionally doped.

[0037] S8. Maintain the temperature at 680℃, introduce TMGa, PH3, and AsH3 to grow the P-side barrier layer Ga. x As y3 P 1-y3 108, thickness 10nm, unintentional doping.

[0038] S9. Temperature is increased to 740℃ at a rate of 50℃ / min. TMAl, TMGa, AsH3, and PH3 are introduced to grow a P-side graded composition waveguide layer (Al). x4 Ga 1-x4 As 1-z2 P z2 109, thickness 0.15μm, x4 linearly gradient from 0.14 to 0.16, z2=0.025, unintentional doping.

[0039] S10, temperature maintained at 740℃, TMAl, TMGa and AsH3 introduced, constant composition waveguide layer Al on P side. x5 Ga 1-x5 As110, thickness 0.1 μm, doping concentration 9 × 10⁻⁶ 17 Atoms / cm³, with CBr4 as the P-type doping source.

[0040] S11. Increase the temperature to 800℃ at a rate of 50℃ / min, introduce TMAl, TMGa, and AsH3, and grow the P-side confinement layer A. lx6 Ga 1-x6 As 111, thickness 0.3 μm, doping concentration 1.5 × 10⁻⁶ 18 Atoms / cm³, with CBr4 as the P-type doping source.

[0041] S12, the temperature is reduced to 550℃, TMGa and AsH3 are introduced to grow a GaAs ohmic contact layer 112 with a thickness of 600nm and a doping concentration of 3.5×10⁻⁶. 19 Atoms / cm³, with CBr4 as the P-type doping source.

[0042] Comparative Example 1 Comparative Example 1 provides a conventional 980nm high-power semiconductor laser epitaxial wafer, whose structure, from bottom to top along the growth direction, consists of: GaAs substrate 2-1, GaAs buffer layer 2-2, N-side confinement layer 2-3, N-side waveguide layer 2-4, N-side barrier layer 2-5, quantum well 2-6, P-side barrier layer 2-7, P-side waveguide layer 2-8, P-side confinement layer 2-9, and GaAs ohmic contact layer 2-10.

[0043] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not include the combined design of the first N-side graded component waveguide layer, the second N-side graded component waveguide layer (containing P-tension strain), the P-side graded component waveguide layer and the P-side constant component waveguide layer of the present invention.

[0044] The other steps and conditions are the same as in Example 1.

[0045] Test case The electrical parameters of the 980nm high-power semiconductor laser epitaxial wafers prepared in Examples 1-2 and Comparative Example 1 were tested, and the test data are shown in Table 1 below.

[0046] Table 1 Electrical parameters of Implementation 1-2 and Comparative Example under the same process.

[0047] As shown in Table 1, the COD current in Example 1 increased from 78A to 92A, an increase of 17.9%, and the COD power increased from 70W to 85W, an increase of 21.4%. In Example 2, the COD current increased to 90A and the COD power increased to 84W, both significantly better than Comparative Example 1. This indicates that the present invention broadens the optical field towards the N-side through an asymmetric graded waveguide to reduce the cavity surface optical power density. Furthermore, by combining a segmented strain waveguide containing P-elements in AlGaAsP to introduce tensile strain, the material bandgap is increased, intrinsic interband absorption is reduced, and overall structural strain compensation is achieved. This effectively reduces cavity surface heat accumulation and significantly enhances the device's COD resistance and reliability.

[0048] Meanwhile, while maintaining the same output power of 45W, the threshold current in Example 1 decreased from 2.15A to 2.05A, the operating voltage decreased from 1.62V to 1.57V, and the slope efficiency increased from 0.96W / A to 1.1W / A; in Example 2, the threshold current decreased to 2.04A, the operating voltage decreased to 1.56V, and the slope efficiency also increased to 1.1W / A. This demonstrates that while broadening the optical field and introducing a tensile strain waveguide, this invention effectively maintains and optimizes the optical confinement factor and carrier transport efficiency by optimizing the gradient composition design and gradient doping distribution, avoiding the problems of decreased confinement factor and deteriorated static electrical parameters caused by asymmetric waveguides in the prior art.

[0049] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A 980nm high-power semiconductor laser epitaxial wafer, characterized in that, The epitaxial wafer, from bottom to top along the growth direction, consists of: GaAs substrate, GaAs buffer layer, N-side confinement layer, first N-side graded composition waveguide layer, second N-side graded composition waveguide layer, N-side barrier layer, quantum well, P-side barrier layer, P-side graded composition waveguide layer, P-side constant composition waveguide layer, P-side confinement layer, and GaAs ohmic contact layer. The first N-side graded-component waveguide layer is Al x2 Ga 1-x2 As, where 0.15≤x2≤0.4, x2 changes linearly in the range of 0.15~0.4, gradually changing from a high value to a low value; The second N-side graded-component waveguide layer is Al x3 Ga 1-x3 As 1-z1 P z1 Where 0.12≤x3≤0.25, 0.01≤z1≤0.04, and x3 gradually changes linearly within the range of 0.12 to 0.25, from high value to low value; The P-side graded component waveguide layer is Al. x4 Ga 1-x4 As 1-z2 P z2 Where 0.12≤x4≤0.18, 0.01≤z2≤0.04, and x4 gradually changes linearly within the range of 0.12 to 0.18, from low to high values; The P-side constant composition waveguide layer is Al. x5 Ga 1-x5 As, where 0.14≤x5≤0.

18.

2. The 980nm high-power semiconductor laser epitaxial wafer as described in claim 1, characterized in that, The first N-side graded component waveguide layer Al x2 Ga 1-x2 In As, x2 linearly varies from 0.3 to 0.18; the second N-side graded-component waveguide layer Al x3 Ga 1-x3 As 1-z1 P z1 In the middle, x3 linearly decreases from 0.18 to 0.14; the P-side graded component waveguide layer Al x4 Ga 1-x4 As 1-z2 P z2 In the middle, x4 gradually changes linearly from 0.14 to 0.

16.

3. The epitaxial wafer for a 980nm high-power semiconductor laser as described in claim 1, characterized in that, The first N-side graded component waveguide layer Al x2 Ga 1-x2 The thickness of the As layer is 0.3~0.5μm, and the doping method is graded doping with a doping concentration of 8×10⁻⁶. 16 ~2×10 17 atoms / cm³; the second N-side graded-component waveguide layer Al x3 Ga 1-x3 As 1-z1 P z1 The thickness is 0.1~0.4μm, and it is not intentionally doped.

4. The epitaxial wafer for a 980nm high-power semiconductor laser as described in claim 3, characterized in that, The first N-side graded component waveguide layer Al x2 Ga 1-x2 The thickness of As is 0.4 μm; the second N-side graded composition waveguide layer Al x3 Ga 1- x3 As 1-z1 P z1 The thickness is 0.25 μm.

5. The epitaxial wafer for a 980nm high-power semiconductor laser as described in claim 1, characterized in that, P-side graded component waveguide layer Al x4 Ga 1-x4 As 1-z2 P z2 The thickness is 0.1~0.2μm, and it is not intentionally doped; the P-side constant composition waveguide layer Al x5 Ga 1-x5 The thickness of the As oxide layer is 0.1~0.3μm, and the doping source is CBr4 with a doping concentration of 6×10⁻⁶. 17 ~2×10 18 atoms / cm³.

6. The 980nm high-power semiconductor laser epitaxial wafer as described in claim 5, characterized in that, P-side graded component waveguide layer Al x4 Ga 1-x4 As 1-z2 P z2 The thickness is 0.15 μm; the P-side constant composition waveguide layer Al x5 Ga 1-x5 The thickness of the As layer is 0.12 μm, and the doping concentration is 9 × 10⁻⁶. 17 atoms / cm³.

7. The epitaxial wafer for a 980nm high-power semiconductor laser as described in claim 1, characterized in that, The GaAs buffer layer has a thickness of 300~350nm and a doping concentration of 2×10⁻⁶. 18 ~5×10 18 atoms / cm³; The N-side confinement layer is Al. x1 Ga 1-x1 As, with a thickness of 1.2~1.6μm and a doping concentration of 1.5×10⁻⁶. 18 ~2.5×10 18 atoms / cm³; The N-side barrier layer is GaAs. y1 P 1-y1 The thickness is 10~20nm, and it is not intentionally doped; The quantum well is In y2 Ga 1-y2 As, with a thickness of 5~10nm, is not intentionally doped; The P-side barrier layer is Ga. x As y3 P 1-y3 The thickness is 10~20nm, and it is not intentionally doped; The P-side confinement layer is A. lx6 Ga 1-x6 As, with a thickness of 0.3~0.5μm and a doping concentration of 1×10⁻⁶. 18 ~2×10 18 atoms / cm³; The thickness of the GaAs ohmic contact layer is 500~700 nm, and the doping concentration is 2.5×10⁻⁶. 19 ~4.5×10 19 atoms / cm³.

8. The epitaxial wafer for a 980nm high-power semiconductor laser as described in claim 7, characterized in that, The GaAs buffer layer has a thickness of 320 nm and a doping concentration of 4 × 10⁻⁶. 18 atoms / cm³; The N-side confinement layer Al x1 Ga 1-x1 The thickness of the As layer is 1.4 μm, and the doping concentration is 2 × 10⁻⁶. 18 atoms / cm³; The N-side barrier layer is GaAs. y1 P 1-y1 The thickness is 17nm, and it is not intentionally doped; The quantum well In y2 Ga 1-y2 The thickness of As is 8.5 nm, which is not intentionally doped; The P-side barrier layer GaAs y3 P 1-y3 The thickness is 17nm, and it is not intentionally doped; The P-side confinement layer Al x6 Ga 1-x6 The thickness of the As layer is 0.4 μm, and the doping concentration is 1.5 × 10⁻⁶. 18 atoms / cm³; The GaAs ohmic contact layer has a thickness of 600 nm and a doping concentration of 3.5 × 10⁻⁶. 19 atoms / cm³.

9. The epitaxial wafer for a 980nm high-power semiconductor laser as described in claim 7, characterized in that, The N-side confinement layer Al x1 Ga 1-x1 The doping source for As is Si2H6; the P-side confinement layer Al x6 Ga 1-x6 The doping source for As is CBr4; the doping source for the GaAs ohmic contact layer is CBr4.

10. A method for fabricating a 980nm high-power semiconductor laser epitaxial wafer as described in any one of claims 1-9, characterized in that, The method includes the following steps: S1. Place the GaAs substrate in the MOCVD reaction chamber, heat the H2 environment to 500-550℃, then introduce AsH3, and heat the temperature to 790-830℃ for 40-50 minutes. S2. The temperature is reduced to 670-690℃, and the cooling rate is no higher than 40℃ / min. MO source TMGa and AsH3 are introduced to grow a GaAs buffer layer on the GaAs substrate. S3. Increase the temperature to 730-750℃, with a heating rate not exceeding 50℃ / min, and introduce TMAl, TMGa, and AsH3 to grow an N-side confinement layer Al on the GaAs buffer layer. x1 Ga 1-x1 As; S4. Maintain the temperature at 730-750℃, introduce TMAl, TMGa, and AH3, and confine the Al layer on the N-side. x1 Ga 1-x1 A first N-side graded-component waveguide layer Al is grown on As. x2 Ga 1-x2 As; S5. Maintain the temperature at 730-750℃, introduce TMAl, TMGa, and AH3, PH3, and apply Al to the graded waveguide layer on the first N-side. x2 Ga 1-x2 A second N-side graded-component waveguide layer Al is grown on As. x3 Ga 1--x3 As 1-z1 P z1 ; S6. Temperature is reduced to 670-690℃, with a cooling rate not exceeding 40℃ / min. TMGa, AsH3, and PH3 are introduced, and the Al phased-component waveguide layer on the second N-side is... x3 Ga 1--x3 As 1-z1 P z1 On-grown N-side barrier layer GaAs y1 P 1-y1 ; S7. Maintain the temperature at 670-690℃, introduce TMGa, TMIn, and AsH3, and then introduce GaAs on the N-side barrier layer. y1 P 1-y1 On-grown quantum well In y2 Ga 1-y2 As; S8, with the temperature maintained at 670-690℃, TMGa, PH3, and AsH3 are introduced into the quantum well In. y2 Ga 1-y2 GaAs with P-barrier layer grown on As y3 P 1-y3 ; S9. Raise the temperature to 730-750℃, with a heating rate not exceeding 50℃ / min, and introduce TMAl, TMGa, and AH3 into the GaAs barrier layer on the p-side. y3 P 1-y3 On-grown P-side graded composition waveguide layer Al x4 Ga 1-x4 As 1-z2 P z2 ; S10, with the temperature maintained at 730-750℃, introduces TMAl, TMGa, and AsH3, and performs graded composition waveguide layer Al on the P-side. x4 Ga 1- x4 As 1-z2 P z2 On-grown P-side constant composition waveguide layer Al x5 Ga 1-x5 As; S11. The temperature is raised to 790-810℃, with a heating rate not exceeding 50℃ / min. TMAl, TMGa, and AsH3 are introduced, and the Al waveguide layer on the P side is kept constant in composition. x5 Ga 1-x5 As grows a P-side confinement layer Al x6 Ga 1-x6 As; S12, the temperature is reduced to 540-560℃, TMGa and AsH3 are introduced, and Al is used as the confinement layer on the P side. x6 Ga 1-x6 A GaAs ohmic contact layer is grown on As.

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