High-power low-divergence-angle 915nm semiconductor laser epitaxial wafer with refractive index modulation structure and preparation method of high-power low-divergence-angle 915nm semiconductor laser epitaxial wafer

Abstract

The invention provides a high-power low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure and a preparation method of the high-power low-divergence-angle 915nm semiconductor laser epitaxial wafer. The laser epitaxial wafer comprises a substrate, a buffer layer, an N limiting layer, an N passive waveguide layer, an N reverse waveguide layer, an N active waveguide layer, an Al < x > 5Ga < 1-x > 5As barrier layer, a quantum well layer, an Al < x > 8Ga < 1-x > 8As barrier layer, a P active waveguide layer, a P expansion waveguide layer, a P passive waveguide layer, a P limiting layer and an ohmic contact layer. The low-refractive-index reverse waveguide layer is inserted between the N-side active waveguide layer and the passive waveguide layer, an optical field is adjusted to deviate to the low-loss N side, optical loss is reduced, and the output power limit is improved. And an expansion waveguide layer is inserted between the P-side active waveguide layer and the passive waveguide layer, and a high-order mode is regulated and controlled to deviate to the P side for loss, so that fundamental mode lasing is realized. By designing a novel epitaxial structure, the output power limit is optimized, and the far-field divergence angle is reduced.

Description

Technical Field

[0001] This invention relates to a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure and its fabrication method, belonging to the field of optoelectronic technology. Background Technology

[0002] GaAs-based 915nm high-power semiconductor lasers, after years of development, possess advantages such as high power and small size, and are now widely used in important fields such as solid-state laser pump sources, advanced industrial manufacturing, laser communication, and medical aesthetics. In recent years, high-power laser diodes (LDs) have seen significant performance improvements and are widely used in fiber lasers, solid-state lasers, and infrared illumination. With the rapid development of lidar and laser ranging in recent years, applications are further subdivided into long-range and short-range applications based on detection distance. As the core light source of lidar, short-range applications primarily focus on the divergence angle of the semiconductor laser. The size of the divergence angle determines the intensity dissipation at long distances and the detection range for low-reflectivity, small targets. A smaller divergence angle results in higher laser brightness, stronger unidirectionality, stronger light intensity illuminating the target, and higher detection accuracy, making it easier to determine the target's spot position in close-range testing. Furthermore, all these applications require the highest possible optical power, high efficiency, and good beam quality. To manufacture laser diodes that meet these requirements, their structural design must ensure a high catastrophic optical damage (COD) threshold, low internal optical loss, and low thermal resistance (Rth) and electrical resistance (Rs). Currently, further improving the optoelectronic performance of single chips is the main challenge.

[0003] The COD threshold can usually be improved by changing the material system, laser end-face passivation, and coating techniques. However, increasing the output power limit of a laser diode requires expanding its emission area, which means increasing the effective thickness of the heterostructure waveguide. Currently, there are three main waveguide design methods for the far-field emission angle of laser chips: narrow waveguides, extended waveguides, and ultra-large cavities. Narrow waveguide designs often come at the cost of a reduced optical confinement factor and increased threshold current. Simultaneously, the optical field leaks into the highly doped confinement layer region, reducing the laser's slope efficiency, making it unsuitable for low-power applications. Ultra-large cavity structures result in a small optical confinement factor and a relatively large threshold current, also unsuitable for low-power applications. Furthermore, the thicker waveguide can lead to higher-order mode lasing. Extended waveguide structures increase the near-field spot size and reduce the far-field divergence angle by adding a mode extension layer to the confinement layer. However, this structure increases the material's series resistance and the operating voltage.

[0004] Therefore, how to design novel epitaxial structures to optimize the output power limit, reduce the far-field divergence angle, and effectively confine carriers, thereby achieving low loss, high output power, and electro-optical conversion efficiency, remains a critical problem that urgently needs to be solved. To this end, this invention is proposed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure and its fabrication method. This invention optimizes the output power limit and reduces the far-field divergence angle by designing a novel epitaxial structure, while simultaneously achieving effective carrier confinement, thereby realizing low loss, high output power, and high electro-optical conversion efficiency.

[0006] The technical solution of the present invention is as follows: A high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure, comprising, from bottom to top: a GaAs substrate, a GaAs buffer layer, and an Al... x1 Ga 1-x1 As N confinement layer, Al x2 Ga 1-x2 As N passive waveguide layer, Al x3 Ga 1-x3 As N anti-waveguide layer, Al x4 Ga 1-x4 As N active waveguide layer, Al x5 Ga 1-x5 As barrier layer, In (x6~x7) Ga (1-x6~1-x7) As quantum well layer, Al x8 Ga 1-x8 As barrier layer, Al x9 Ga 1-x9 As P active waveguide layer, Al x10 Ga 1-x10 As P extended waveguide layer, Al x11 Ga 1-x11 As P passive waveguide layer, Al x12 Ga 1-x12 As P confinement layer, GaAs ohmic contact layer; 0.4≤x1≤0.7, 0.2≤x2≤0.5, 0.5≤x3≤0.8, 0.2≤x4≤0.5, 0.1≤x5≤0.5, 0.1≤x6≤0.15, 0.15≤x7≤0.2, 0.1≤x8≤0.5, 0.2≤x9≤0.5, 0.1≤x10≤0.3, 0.2≤x11≤0.5, 0.5≤x12≤0.8.

[0007] According to a preferred embodiment of the present invention, the thickness of the N-waveguide layer is greater than the thickness of the P-waveguide layer; the thickness of the N-waveguide layer is Al. x2 Ga 1-x2 As N passive waveguide layer, Al x3 Ga 1-x3 As N anti-waveguide layer and Al x4 Ga 1-x4 As is the total thickness of the N-type active waveguide layer, and the thickness of the P-type waveguide layer is Al. x9 Ga 1-x9 As P active waveguide layer, Al x10 Ga 1-x10 As P extended waveguide layer and Al x11 Ga 1-x11 The total thickness of the As P passive waveguide layer.

[0008] According to a preferred embodiment of the present invention, the In (x6~x7) Ga (1-x6~1-x7) As the In composition of the quantum well layer is close to Al x5 Ga 1- x5 As the direction of the barrier layer is from In x6 Ga 1-x6 As to In x7 Ga 1-x7 As increases linearly.

[0009] According to the preferred embodiment of the present invention, x1=0.6, x2=0.3, x3=0.5, x4=0.3, x5=0.2, x6=0.12, x7=0.18, x8=0.2, x9=0.45, x10=0.2, x11=0.45, and x12=0.65.

[0010] According to a preferred embodiment of the present invention, the thickness of the GaAs buffer layer is 100~300nm, more preferably 200nm; the Al x1 Ga 1-x1 The thickness of the As N confinement layer is 0.7~1.5μm, more preferably 0.9μm; the Al x2 Ga 1-x2 The thickness of the As N passive waveguide layer is 0.4~0.7μm, more preferably 0.6μm; the Al x3 Ga 1-x3 The thickness of the As N anti-waveguide layer is 15~30nm, more preferably 25nm; the Al x4 Ga 1-x4 The thickness of the As N active waveguide layer is 0.3~0.5μm, more preferably 0.4μm; the Al x5 Ga 1-x5The thickness of the As barrier layer is 15~30nm, more preferably 20nm; the In (x6~x7) Ga (1-x6~1-x7) The thickness of the As quantum well layer is 6~11nm, more preferably 8nm; the Al x8 Ga 1-x8 The thickness of the As barrier layer is 15~30nm, more preferably 20nm; the Al x9 Ga 1-x9 The thickness of the As P active waveguide layer is 0.1~0.3μm, more preferably 0.2μm; the Al x10 Ga 1-x10 The thickness of the As P extended waveguide layer is 0.1~0.2μm, more preferably 0.15μm; the Al x11 Ga 1-x11 The thickness of the As P passive waveguide layer is 0.1~0.3μm, more preferably 0.2μm; the Al x12 Ga 1- x12 The thickness of the As P confinement layer is 0.3~0.6μm, more preferably 0.5μm; the thickness of the GaAs ohmic contact layer is 100~300nm, more preferably 200nm.

[0011] According to the present invention, the method for fabricating the above-mentioned high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with refractive index modulation structure includes the following steps: performing surface heat treatment on the substrate in an MOCVD growth chamber, and epitaxially growing a GaAs buffer layer and an Al layer sequentially from bottom to top on the substrate using MOCVD technology. x1 Ga 1-x1 As N confinement layer, Al x2 Ga 1-x2 As N passive waveguide layer, Al x3 Ga 1-x3 As N anti-waveguide layer, Al x4 Ga 1-x4 As N active waveguide layer, Al x5 Ga 1-x5 As barrier layer, In (x6~x7) Ga (1-x6~1-x7) As quantum well layer, Al x8 Ga 1-x8 As barrier layer, Al x9 Ga 1-x9 As P active waveguide layer, Al x10 Ga 1-x10 As P extended waveguide layer, Al x11 Ga 1-x11 As P passive waveguide layer, Al x12 Ga1-x12 As P confinement layer, GaAs ohmic contact layer.

[0012] According to the present invention, the above-described epitaxial growth method can be carried out using existing technology; preferably, the method for preparing a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure includes the following steps: (1) Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 710~730℃ and bake for 20~40 minutes, then introduce AsH3 to perform high-temperature heat treatment on the GaAs substrate to remove water and oxygen from the substrate surface. (2) Control the temperature of the reaction chamber to 660~680℃, and the cooling rate should not exceed 30℃ / min. Then introduce TMGa and AsH3 to grow a GaAs buffer layer on the GaAs substrate. (3) The reaction chamber temperature is maintained at 660~680℃, and TMAl, TMGa and AsH3 are introduced to grow Al on the GaAs buffer layer. x1 Ga 1-x1 As N confinement layer; (4) The reaction chamber temperature is maintained at 660~680℃, and TMAl, TMGa and AsH3 are introduced into the Al x1 Ga 1-x1 Al grown on N-confinement layer x2 Ga 1-x2 As N passive waveguide layer; (5) The reaction chamber temperature is controlled at 690~710℃, and TMAl, TMGa and AsH3 are introduced into Al x2 Ga 1-x2 Al grown on N passive waveguide layer x3 Ga 1-x3 As N anti-waveguide layer, unintentionally doped; (6) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al. x3 Ga 1-x3 Al grown on N-type anti-waveguide layer x4 Ga 1-x4 As N active waveguide layer, unintentionally doped; (7) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x4 Ga 1-x4 Al is grown on the N active waveguide layer. x5 Ga 1-x5 As a barrier layer, unintentionally doped; (8) The reaction chamber temperature is maintained at 660~680℃, and TMGa, TMIn, and AsH3 are introduced into Al. x5Ga 1-x5 As barrier layer grows In (x6~x7) Ga (1-x6~1-x7) As a quantum well layer, the In composition changes linearly, and the In composition of the quantum well layer changes from In during its growth cycle. x6 Ga 1-x6 As to In x7 Ga 1-x7 As increases linearly, unintentional doping; (9) The reaction chamber temperature is maintained at 660~680℃, and TMAl, TMGa and AsH3 are introduced into In (x6~x7) Ga (1-x6~1-x7) Al grown on As quantum well layer x8 Ga 1-x8 As a barrier layer, unintentionally doped; (10) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x8 Ga 1-x8 Al grows on the As barrier layer x9 Ga 1-x9 As P active waveguide layer, unintentionally doped; (11) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x9 Ga 1-x9 Al is grown on the P active waveguide layer. x10 Ga 1-x10 As P extended waveguide layer, unintentionally doped; (12) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x10 Ga 1-x10 Al grown on As P extended waveguide layer x11 Ga 1-x11 As P passive waveguide layer, unintentionally doped; (13) The reaction chamber temperature is controlled at 690~710℃, and TMAl, TMGa and AsH3 are introduced into Al x11 Ga 1-x11 Al grown on P passive waveguide layer x12 Ga 1-x12 As P confinement layer; (14) Lower the reaction chamber temperature to 540~560℃, introduce TMGa and AsH3, and in Al x12 Ga 1-x12 GaAs ohmic contact layers are grown on As P confinement layers.

[0013] According to a preferred embodiment of the present invention, in step (1), the temperature is raised to 720°C and baked for 30 minutes.

[0014] According to a preferred embodiment of the present invention, in step (2), the reaction chamber temperature is controlled at 670°C, and the doping concentration is 1E18~5E18 atoms / cm³. 3 Further preferred is 2E18 atoms / cm 3 The doping source is Si2H6.

[0015] According to a preferred embodiment of the present invention, in step (3), the reaction chamber temperature is controlled at 670°C and the doping concentration is 6E17~1E19 atoms / cm³. 3 Further preferred is 8E17 atoms / cm 3 The doping source is Si2H6.

[0016] According to a preferred embodiment of the present invention, in step (4), the reaction chamber temperature is controlled at 670°C and the doping concentration is 2E17~1E18 atoms / cm³. 3 Further preferred is 5E17 atoms / cm 3 The doping source is Si2H6.

[0017] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 700°C in step (5).

[0018] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 670°C in step (6).

[0019] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 670°C in step (7).

[0020] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 670°C in step (8).

[0021] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 670°C in step (9).

[0022] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 670°C in step (10).

[0023] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 670°C in step (11).

[0024] According to a preferred embodiment of the present invention, the temperature of the reaction chamber is controlled at 670°C in step (12).

[0025] According to a preferred embodiment of the present invention, in step (13), the reaction chamber temperature is controlled at 700°C and the doping concentration is 7E17~2E18 atoms / cm³. 3 Further preferred is 8E17 atoms / cm 3 The doping source is CBr4.

[0026] According to a preferred embodiment of the present invention, in step (14), the reaction chamber temperature is controlled at 550°C and the doping concentration is 9E18~5E19 atoms / cm³. 3 Further preferred is 4E19 atoms / cm 3 The doping source is CBr4.

[0027] The technical features and beneficial effects of this invention are as follows: This invention employs a refractive index modulated epitaxial structure. A low-refractive-index anti-waveguide layer is inserted between the N-side active and passive waveguide layers to adjust the optical field towards the low-loss N-side, reducing optical loss and increasing the output power limit. An extended waveguide layer is inserted between the P-side active and passive waveguide layers to modulate higher-order modes towards the P-side for loss, thereby achieving fundamental mode lasing. Both the N and P waveguide layers are designed to increase the near-field spot size, thereby reducing the far-field divergence angle. Simultaneously, the refractive index difference between the quantum well and the P-waveguide is increased. While effectively limiting carrier leakage, the optical field distribution is modulated through refractive index guidance, reducing base film optical field loss and increasing lasing power. Ultimately, high output power and superior far-field characteristics are achieved, improving the overall optoelectronic performance of the device. Attached Figure Description

[0028] Figure 1 The diagram shows the structure (a) and refractive index structure (b) of the epitaxial wafer of the high-power, low-divergence-angle 915nm semiconductor laser with refractive index modulation structure in Example 1.

[0029] Figure 2 The diagram shows the structure (a) and refractive index structure (b) of the epitaxial wafer of the 915nm semiconductor laser, which is shown in Comparative Example 1.

[0030] Figure 3 The image shows the spectral test results of the epitaxial wafer of the high-power, low-divergence-angle 915nm semiconductor laser with refractive index modulation structure in Example 1 after packaging.

[0031] Wherein, 1 is a GaAs substrate, 2 is a GaAs buffer layer, and 3 is an Al... x1 Ga 1-x1 As N confinement layer, 4 is Al x2 Ga 1-x2 As N is a passive waveguide layer, 4' is Al 0.45 Ga 0.55 As N waveguide layer, 5 is Al x3 Ga 1-x3 As N anti-waveguide layer, 6 is Al x4 Ga 1-x4 As N active waveguide layer, 7 is Al x5 Ga 1-x5 As barrier layer, 8 is In (x6~x7) Ga(1-x6~1-x7) As quantum well layer, 8' is In 0.15 Ga 0.85 As quantum well layer, 9 is Al x8 Ga 1-x8 As barrier layer, 10 is Al x9 Ga 1-x9 As P is the active waveguide layer, 10' is Al 0.45 Ga 0.55 As P waveguide layer, 11 is Al x10 Ga 1-x10 As P extended waveguide layer, 12 is Al x11 Ga 1-x11 As P passive waveguide layer, 13 is Al x12 Ga 1-x12 As is the P-confined layer, and 14 is the GaAs ohmic contact layer. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments and accompanying drawings, but is not limited thereto. The described embodiments are some embodiments of the present invention. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be noted that the terms "upper" and "lower" and other terms indicating orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and should not be construed as limiting this invention.

[0034] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Unless otherwise specified in the embodiments of the present invention, all techniques existing in the art can be used.

[0035] An epitaxial wafer for a high-power, low-divergence-angle 915nm semiconductor laser with a refractive index modulation structure, such as Figure 1 As shown, from bottom to top, it includes a GaAs substrate 1, a GaAs buffer layer 2, and an Al layer 3. x1 Ga 1-x1 As N confinement layer 3, Al x2 Ga 1-x2 As N passive waveguide layer 4, Al x3 Ga 1-x3 As N anti-waveguide layer 5, Al x4 Ga 1-x4 As N active waveguide layer 6, Al x5 Ga 1-x5 As barrier layer 7, In (x6~x7) Ga (1-x6~1-x7) As quantum well layer 8, Alx8 Ga 1-x8 As barrier layer 9, Al x9 Ga 1-x9 As P active waveguide layer 10, Al x10 Ga 1-x10 As P extended waveguide layer 11, Al x11 Ga 1-x11 As P passive waveguide layer 12, Al x12 Ga 1-x12 As P confinement layer 13, GaAs ohmic contact layer 14; wherein, 0.4≤x1≤0.7, 0.2≤x2≤0.5, 0.5≤x3≤0.8, 0.2≤x4≤0.5, 0.1≤x5≤0.5, 0.1≤x6≤0.15, 0.15≤x7≤0.2, 0.1≤x8≤0.5, 0.2≤x9≤0.5, 0.1≤x10≤0.3, 0.2≤x11≤0.5, 0.5≤x12≤0.8.

[0036] The core technology of this invention is based on the theory of "bandgap engineering." The quantum well layer adopts a compositionally graded structure, with the narrowest bandgap near the P-waveguide. Electron leakage to the P-side is reduced by increasing the bandgap. The overall waveguide layer design employs an asymmetric structure, with the N-waveguide being thicker than the P-waveguide. The N-side waveguide layer uses a three-waveguide structure, inserting a low-refractive-index anti-waveguide layer between the active and passive waveguides. Through refractive index guidance, the local waveguide / anti-waveguide competition is controlled, causing the light field to deflect towards the N-side, reducing absorption loss, and improving the output power limit and catastrophic optical damage threshold. Simultaneously, the near-field spot size is increased, and the far-field divergence angle is optimized. Since asymmetric design is prone to triggering higher-order mode lasing, an extended waveguide layer is inserted when designing the P-side waveguide. The overlap between the higher-order modes and the high-loss P-waveguide layer and P-confining layer is much greater than that of the base film. Taking advantage of the large overlap between the higher-order modes and the P-side, the higher-order modes are guided to penetrate into the high-loss P-side to the maximum extent, thereby reducing the loss of the higher-order modes and achieving lasing of the base film, thus optimizing the far-field divergence angle.

[0037] The present invention will be further described in detail below with reference to specific embodiments.

[0038] Example 1 A method for fabricating a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure includes the following steps: (1) Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 720°C and bake for 30 minutes, then introduce AsH3 to perform high-temperature heat treatment on the GaAs substrate to remove water and oxygen from the substrate surface. (2) The temperature of the reaction chamber was slowly reduced to 670℃ at a rate of 20℃ / min. TMGa and AsH3 were introduced to grow a GaAs buffer layer with a thickness of 200nm on the GaAs substrate. The doping source of the GaAs buffer layer was Si2H6, and the doping concentration was 2E18 atoms / cm. 3 ; (3) The reaction chamber temperature was maintained at 670℃, and TMAl, TMGa and AsH3 were introduced to grow Al with a thickness of 0.9 μm on the GaAs buffer layer. x1 Ga 1-x1 As N is a confinement layer, x1=0.6; Al x1 Ga 1-x1 The doping source for the As N confinement layer is Si2H6, with a doping concentration of 8E17 atoms / cm³. 3 , (4) The reaction chamber temperature is maintained at 670℃, and TMAl, TMGa and AsH3 are introduced into the Al x1 Ga 1-x1 Al with a thickness of 0.6 μm is grown on an As N confinement layer. x2 Ga 1-x2 As N is a passive waveguide layer, x2=0.3; Al x2 Ga 1-x2 The doping source for the As N passive waveguide layer is Si2H6, with a doping concentration of 5E17 atoms / cm³. 3 ; (5) The reaction chamber temperature is controlled at 700℃, and TMAl, TMGa and AsH3 are introduced into Al. x2 Ga 1-x2 Al with a thickness of 25 nm is grown on an As N passive waveguide layer. x3 Ga 1-x3 As N anti-waveguide layer, x3=0.5, unintentionally doped; (6) The reaction chamber temperature is controlled at 670℃, and TMAl, TMGa and AsH3 are introduced into the Al x3 Ga 1-x3 An Al layer with a thickness of 0.4 μm is grown on an As N anti-waveguide layer. x4 Ga 1-x4 As N active waveguide layer, x4=0.3, unintentionally doped; (7) The reaction chamber temperature is controlled at 670℃, and TMAl, TMGa and AsH3 are introduced into Al. x4 Ga 1-x4 An Al layer with a thickness of 20 nm is grown on an As N active waveguide layer. x5 Ga 1-x5 As barrier layer, x5=0.2, unintentionally doped; (8) The reaction chamber temperature is maintained at 670℃, and TMGa, TMIn, and AsH3 are introduced into Al. x5 Ga 1-x5 An 8nm thick In substrate is grown on the As barrier layer. (x6~x7) Ga (1-x6~1-x7) As quantum well layer, x6=0.12, x7=0.18; In composition changes linearly, the In composition of the quantum well layer changes from In to In during its growth cycle. x6 Ga 1-x6 As to In x7 Ga 1-x7 As increases linearly, unintentional doping; (9) The reaction chamber temperature is maintained at 670℃, and TMAl, TMGa and AsH3 are introduced into In (x6~x7) Ga (1-x6~1-x7) Al with a thickness of 20 nm is grown on the As quantum well layer. x8 Ga 1-x8 As barrier layer, x8=0.2, unintentionally doped; (10) The reaction chamber temperature is controlled at 670℃, and TMAl, TMGa and AsH3 are introduced into the Al x8 Ga 1-x8 Al with a thickness of 0.2 μm is grown on the As barrier layer. x9 Ga 1-x9 As P active waveguide layer, x9=0.45, unintentionally doped; (11) The reaction chamber temperature is controlled at 670℃, and TMAl, TMGa and AsH3 are introduced into Al x9 Ga 1-x9 An Al layer with a thickness of 0.15 μm is grown on an As P active waveguide layer. x10 Ga 1-x10 As P extended waveguide layer, x10=0.2, unintentionally doped; (12) The reaction chamber temperature is controlled at 670℃, and TMAl, TMGa and AsH3 are introduced into Al x10 Ga 1-x10 An Al layer with a thickness of 0.2 μm is grown on an As P extended waveguide layer. x11 Ga 1-x11 As P passive waveguide layer, x11=0.45, unintentionally doped; (13) The reaction chamber temperature is controlled at 700℃, and TMAl, TMGa and AsH3 are introduced into Al x11 Ga 1-x11 An Al layer with a thickness of 0.5 μm is grown on an As P passive waveguide layer. x12 Ga 1-x12 As P confinement layer, x12=0.65; Al x12 Ga1-x12 The doping source for the As P confinement layer is CBr4, with a doping concentration of 8E17 atoms / cm³. 3 ; (14) Control the temperature of the reaction chamber to drop to 550℃, introduce TMGa and AsH3, and in Al x12 Ga 1-x12 A GaAs ohmic contact layer with a thickness of 200 nm is grown on an As P confinement layer; the doping source of the GaAs ohmic contact layer is CBr4, and the doping concentration is 4E19 atoms / cm. 3 .

[0039] This allows for the fabrication of a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure, such as... Figure 1 As shown, from bottom to top, it includes a GaAs substrate 1, a GaAs buffer layer 2, and an Al layer 3. x1 Ga 1-x1 As N confinement layer 3, Al x2 Ga 1-x2 AsN passive waveguide layer 4, Al x3 Ga 1-x3 As N anti-waveguide layer 5, Al x4 Ga 1-x4 As N active waveguide layer 6, Al x5 Ga 1-x5 As barrier layer 7, In (x6~x7) Ga (1-x6~1-x7) As quantum well layer 8, Al x8 Ga 1-x8 As barrier layer 9, Al x9 Ga 1-x9 As P active waveguide layer 10, Al x10 Ga 1-x10 As P extended waveguide layer 11, Al x11 Ga 1-x11 As P passive waveguide layer 12, Al x12 Ga 1-x12 As P confinement layer 13, GaAs ohmic contact layer 14; Where x1=0.6, x2=0.3, x3=0.5, x4=0.3, x5=0.2, x6=0.12, x7=0.18, x8=0.2, x9=0.45, x10=0.2, x11=0.45, x12=0.65.

[0040] Comparative Example 1 A method for fabricating a 915nm semiconductor laser epitaxial wafer includes the following steps: (1) Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 720℃ for 30 minutes, and then introduce AsH3 to perform high-temperature heat treatment on the GaAs substrate to remove water and oxygen on the substrate surface. (2) The temperature of the reaction chamber was slowly reduced to 670℃ at a rate of 20℃ / min. TMGa and AsH3 were introduced to grow a GaAs buffer layer with a thickness of 200nm on the GaAs substrate. The doping source of the GaAs buffer layer was Si2H6, and the doping concentration was 2E18 atoms / cm. 3 ; (3) The reaction chamber temperature was maintained at 670℃, and TMAl, TMGa and AsH3 were introduced to grow Al with a thickness of 0.9 μm on the GaAs buffer layer. x1 Ga 1-x1 As N is a confinement layer, x1=0.6; Al x1 Ga 1-x1 The doping source for the As N confinement layer is Si2H6, with a doping concentration of 8E17 atoms / cm³. 3 , (4) The reaction chamber temperature is maintained at 670℃, and TMAl, TMGa and AsH3 are introduced into the Al x1 Ga 1-x1 Al with a thickness of 0.77 μm is grown on an As N confinement layer. 0.45 Ga 0.55 As N-waveguide layer; Al 0.45 Ga 0.55 The doping source for the As N waveguide layer is Si2H6, with a doping concentration of 5E17 atoms / cm². 3 ; (5) The reaction chamber temperature is controlled at 670℃, and TMAl, TMGa and AsH3 are introduced into Al. 0.45 Ga 0.55 Al with a thickness of 20 nm is grown on the As N waveguide layer. x5 Ga 1-x5 As barrier layer, x5=0.2, unintentionally doped; (6) The reaction chamber temperature is maintained at 670℃, and TMGa, TMIn, and AsH3 are introduced into Al. x5 Ga 1-x5 An 8nm thick In substrate is grown on the As barrier layer. 0.15 Ga 0.85 As a quantum well layer, unintentionally doped; (7) The reaction chamber temperature is maintained at 670℃, and TMAl, TMGa and AsH3 are introduced into In 0.15 Ga 0.85 Al with a thickness of 20 nm is grown on the As quantum well layer. x8 Ga1-x8 As barrier layer, x8=0.2, unintentionally doped; (8) The reaction chamber temperature is controlled at 670℃, and TMAl, TMGa and AsH3 are introduced into the Al x8 Ga 1-x8 Al with a thickness of 0.77 μm is grown on the As barrier layer. 0.45 Ga 0.55 As P waveguide layer, unintentionally doped; (9) The reaction chamber temperature is controlled at 700℃, and TMAl, TMGa and AsH3 are introduced into the Al 0.45 Ga 0.55 An Al layer with a thickness of 0.5 μm is grown on an As P waveguide layer. x12 Ga 1-x12 As P confinement layer, x12=0.65; Al x12 Ga 1-x12 The doping source for the As P confinement layer is CBr4, with a doping concentration of 8E17 atoms / cm³. 3 ; (10) Control the temperature of the reaction chamber to drop to 550℃, introduce TMGa and AsH3, and in Al x12 Ga 1-x12 A GaAs ohmic contact layer with a thickness of 200 nm is grown on an As P confinement layer; the doping source of the GaAs ohmic contact layer is CBr4, and the doping concentration is 4E19 atoms / cm. 3 .

[0041] This process yields a 915nm semiconductor laser epitaxial wafer, such as... Figure 2 As shown, from bottom to top, it includes a GaAs substrate 1, a GaAs buffer layer 2, and an Al layer 3. x1 Ga 1-x1 As N confinement layer 3, Al 0.45 Ga 0.55 As N waveguide layer 4', Al x5 Ga 1-x5 As barrier layer 7, In 0.15 Ga 0.85 As quantum well layer 8', Al x8 Ga 1-x8 As barrier layer 9, Al 0.45 Ga 0.55 As P waveguide layer 10', Al x12 Ga 1-x12 As P confinement layer 13, GaAs ohmic contact layer 14; Where x1=0.6, x5=0.2, x8=0.2, and x12=0.65.

[0042] Experimental Example 1 Table 1 compares the electrical parameters of the embodiments and comparative examples under the same process conditions. The operating voltage of the present invention does not change significantly, the power is increased by 1W, the electro-optical conversion efficiency is increased by 7%, the slope efficiency is increased by 0.3W / A, the far-field divergence angle is reduced by 4°, and the threshold current is increased by 0.02A, indicating that the active region light confinement factor of the present invention is slightly reduced. By guiding the refractive index, the light field distribution is controlled, and the light field is further compressed to the N side, reducing absorption loss and increasing output power. The waveguide layer design can expand the near-field spot size, realize the base film lasing, and thus optimize the far-field divergence angle. The thin P-side design can reduce the diode resistance, ultimately achieving high output power and photoelectric conversion efficiency, and improving the overall photoelectric performance of the device.

[0043] Table 1. Comparison of electrical parameters between Comparative Example 1 and Example 1 under the same process. The spectral test results of the laser epitaxial wafer after packaging in Example 1 are as follows: Figure 3 As shown, by Figure 3 It can be seen that the laser epitaxial wafer of the present invention achieves 915nm laser output.

Claims

1. A high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure, characterized in that, From bottom to top, it includes: GaAs substrate, GaAs buffer layer, Al x1 Ga 1-x1 As N confinement layer, Al x2 Ga 1-x2 As N passive waveguide layer, Al x3 Ga 1-x3 As N anti-waveguide layer, Al x4 Ga 1-x4 As N active waveguide layer, Al x5 Ga 1-x5 As barrier layer, In (x6~x7) Ga (1-x6~1-x7) As quantum well layer, Al x8 Ga 1-x8 As barrier layer, Al x9 Ga 1-x9 As P active waveguide layer, Al x10 Ga 1-x10 As P extended waveguide layer, Al x11 Ga 1-x11 As P passive waveguide layer, Al x12 Ga 1-x12 As P confinement layer, GaAs ohmic contact layer; 0.4≤x1≤0.7, 0.2≤x2≤0.5, 0.5≤x3≤0.8, 0.2≤x4≤0.5, 0.1≤x5≤0.5, 0.1≤x6≤0.15, 0.15≤x7≤0.2, 0.1≤x8≤0.5, 0.2≤x9≤0.5, 0.1≤x10≤0.3, 0.2≤x11≤0.5, 0.5≤x12≤0.

8.

2. The high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 1, characterized in that, The thickness of the N-waveguide layer is greater than the thickness of the P-waveguide layer.

3. The high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 1, characterized in that, The In (x6~x7) Ga (1-x6~1-x7) As the In composition of the quantum well layer is close to Al x5 Ga 1-x5 As the direction of the barrier layer is from In x6 Ga 1-x6 As to In x7 Ga 1-x7 As increases linearly.

4. The high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 1, characterized in that, x1=0.6, x2=0.3, x3=0.5, x4=0.3, x5=0.2, x6=0.12, x7=0.18, x8=0.2, x9=0.45, x10=0.2, x11=0.45, x12=0.

65.

5. The high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 1, characterized in that, The thickness of the GaAs buffer layer is 100~300nm, preferably 200nm; the Al x1 Ga 1-x1 The thickness of the As N confinement layer is 0.7~1.5μm, preferably 0.9μm; the Al x2 Ga 1-x2 The thickness of the As N passive waveguide layer is 0.4~0.7μm, preferably 0.6μm; the Al x3 Ga 1-x3 The thickness of the As N anti-waveguide layer is 15~30nm, preferably 25nm; the Al x4 Ga 1-x4 The thickness of the As N active waveguide layer is 0.3~0.5μm, preferably 0.4μm; the Al x5 Ga 1-x5 The thickness of the As barrier layer is 15~30nm, preferably 20nm; the In (x6~x7) Ga (1-x6~1-x7) The thickness of the As quantum well layer is 6~11nm, preferably 8nm; the Al x8 Ga 1-x8 The thickness of the As barrier layer is 15~30nm, preferably 20nm; the Al x9 Ga 1-x9 The thickness of the As P active waveguide layer is 0.1~0.3μm, preferably 0.2μm; the Al x10 Ga 1-x10 The thickness of the As P extended waveguide layer is 0.1~0.2μm, preferably 0.15μm; the Al x11 Ga 1-x11 The thickness of the As P passive waveguide layer is 0.1~0.3μm, preferably 0.2μm; the Al x12 Ga 1-x12 The thickness of the As P confinement layer is 0.3~0.6μm, preferably 0.5μm; the thickness of the GaAs ohmic contact layer is 100~300nm, preferably 200nm.

6. A method for fabricating a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure as described in any one of claims 1-5, characterized in that, The steps include: performing surface heat treatment on the substrate in the MOCVD growth chamber, and epitaxially growing a GaAs buffer layer and an Al layer sequentially from bottom to top on the substrate using MOCVD technology. x1 Ga 1-x1 As N confinement layer, Al x2 Ga 1- x2 As N passive waveguide layer, Al x3 Ga 1-x3 As N anti-waveguide layer, Al x4 Ga 1-x4 As N active waveguide layer, Al x5 Ga 1-x5 As barrier layer, In (x6~x7) Ga (1-x6~1-x7) As quantum well layer, Al x8 Ga 1-x8 As barrier layer, Al x9 Ga 1-x9 As P active waveguide layer, Al x10 Ga 1- x10 As P extended waveguide layer, Al x11 Ga 1-x11 As P passive waveguide layer, Al x12 Ga 1-x12 As P confinement layer, GaAs ohmic contact layer.

7. The method for fabricating a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 6, characterized in that, Includes the following steps: (1) Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 710~730℃ and bake for 20~40 minutes, then introduce AsH3 to perform high-temperature heat treatment on the GaAs substrate to remove water and oxygen from the substrate surface. (2) Control the temperature of the reaction chamber to 660~680℃, and the cooling rate should not exceed 30℃ / min. Then introduce TMGa and AsH3 to grow a GaAs buffer layer on the GaAs substrate. (3) The reaction chamber temperature is maintained at 660~680℃, and TMAl, TMGa and AsH3 are introduced to grow Al on the GaAs buffer layer. x1 Ga 1-x1 As N confinement layer; (4) The reaction chamber temperature is maintained at 660~680℃, and TMAl, TMGa and AsH3 are introduced into the Al x1 Ga 1-x1 Al grown on N-confinement layer x2 Ga 1-x2 As N passive waveguide layer; (5) The reaction chamber temperature is controlled at 690~710℃, and TMAl, TMGa and AsH3 are introduced into Al x2 Ga 1-x2 Al grown on N passive waveguide layer x3 Ga 1-x3 As N anti-waveguide layer, unintentionally doped; (6) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x3 Ga 1-x3 Al grown on N-type anti-waveguide layer x4 Ga 1-x4 As N active waveguide layer, unintentionally doped; (7) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x4 Ga 1-x4 Al is grown on the N active waveguide layer. x5 Ga 1-x5 As a barrier layer, unintentionally doped; (8) The reaction chamber temperature is maintained at 660~680℃, and TMGa, TMIn, and AsH3 are introduced into Al. x5 Ga 1-x5 As barrier layer grows In (x6~x7) Ga (1-x6~1-x7) As a quantum well layer, the In composition changes linearly, and the In composition of the quantum well layer changes from In during its growth cycle. x6 Ga 1-x6 As to In x7 Ga 1-x7 As increases linearly, unintentional doping; (9) The reaction chamber temperature is maintained at 660~680℃, and TMAl, TMGa and AsH3 are introduced into In (x6~x7) Ga (1-x6~1-x7) Al grown on As quantum well layer x8 Ga 1-x8 As a barrier layer, unintentionally doped; (10) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x8 Ga 1-x8 Al grows on the As barrier layer x9 Ga 1-x9 As P active waveguide layer, unintentionally doped; (11) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x9 Ga 1-x9 Al is grown on the As P active waveguide layer x10 Ga 1-x10 As P extended waveguide layer, unintentionally doped; (12) The reaction chamber temperature is controlled at 660~680℃, and TMAl, TMGa and AsH3 are introduced into Al x10 Ga 1-x10 Al grown on As P extended waveguide layer x11 Ga 1-x11 As P passive waveguide layer, unintentionally doped; (13) The reaction chamber temperature is controlled at 690~710℃, and TMAl, TMGa and AsH3 are introduced into Al x11 Ga 1-x11 Al grown on P passive waveguide layer x12 Ga 1-x12 As P confinement layer; (14) Lower the reaction chamber temperature to 540~560℃, introduce TMGa and AsH3, and in Al x12 Ga 1-x12 GaAs ohmic contact layers are grown on As P confinement layers.

8. The method for fabricating a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 7, characterized in that, In step (1), heat the oven to 720℃ and bake for 30 minutes; In step (2), the reaction chamber temperature is controlled at 670℃, and the doping concentration is 1E18~5E18 atoms / cm³. 3 Preferably 2E18 atoms / cm 3 The doping source is Si2H6; In step (3), the reaction chamber temperature is controlled at 670℃, and the doping concentration is 6E17~1E19 atoms / cm³. 3 Preferably 8E17 atoms / cm 3 The doping source is Si2H6; In step (4), the reaction chamber temperature is controlled at 670℃, and the doping concentration is 2E17~1E18 atoms / cm³. 3 Preferably, 5E17 atoms / cm 3 The doping source is Si2H6.

9. The method for fabricating a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 7, characterized in that, In step (5), the temperature of the reaction chamber is controlled at 700℃; In step (6), the temperature of the reaction chamber is controlled at 670℃; In step (7), the temperature of the reaction chamber is controlled at 670℃; In step (8), the temperature of the reaction chamber is controlled at 670℃; In step (9), the temperature of the reaction chamber is controlled at 670℃; In step (10), the temperature of the reaction chamber is controlled at 670℃; In step (11), the temperature of the reaction chamber is controlled at 670℃; In step (12), the temperature of the reaction chamber is controlled at 670℃.

10. The method for fabricating a high-power, low-divergence-angle 915nm semiconductor laser epitaxial wafer with a refractive index modulation structure according to claim 7, characterized in that, In step (13), the reaction chamber temperature is controlled at 700℃, and the doping concentration is 7E17~2E18 atoms / cm³. 3 Preferably 8E17 atoms / cm 3 The doping source is CBr4; In step (14), the reaction chamber temperature is controlled at 550℃, and the doping concentration is 9E18~5E19 atoms / cm³. 3 Preferably, 4E19 atoms / cm 3 The doping source is CBr4.

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