AsH3 flow regulation-based strain compensation type VCSEL epitaxial structure and preparation method thereof

Abstract

The invention discloses an epitaxial structure of a strain compensation type VCSEL (Vertical Cavity Surface Emitting Laser) based on AsH3 flow regulation and control and a preparation method thereof. The epitaxial structure comprises a substrate, and a buffer layer, an N-type DBR (Distributed Bragg Reflector) layer, an active layer, a P-type oxidation limiting layer, a P-type DBR layer and a surface highly-doped GaAs layer are sequentially arranged on the substrate; the N-type DBR layer comprises an N-type high-Al component layer, an Al component transition layer and a low-Al component layer, the P-type DBR layer comprises a P-type high-Al component layer, an Al component transition layer and a low-Al component layer, the active layer comprises a quantum well layer and a quantum barrier layer, the quantum well layer and the quantum barrier layer periodically grow to form the active layer, the quantum well layer is a quantum well layer with compressive strain, and the quantum barrier layer is a quantum well layer with compressive strain. The quantum barrier layer is a tensile strain layer for realizing strain compensation, and the quantum well layer and the quantum barrier layer are alternately arranged to form a periodic structure; the As / P proportion can be accurately controlled to achieve dynamic strain compensation, the As component of the barrier layer is progressively increased to form gradient tensile strain, well layer compression strain is offset, atom mutual diffusion is restrained, P atoms are restrained from diffusing to the well layer, threshold current is reduced, slope efficiency is improved, and characteristic temperature is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor optoelectronic device technology, specifically to an epitaxial structure design and fabrication method for a 660nm vertical cavity surface-emitting laser (VCSEL), and particularly to an innovative scheme for achieving strain compensation by introducing arsine (AsH3) flux gradient modulation in a quantum well barrier layer. Background Technology

[0002] Semiconductor lasers, also known as laser diodes, are lasers that use semiconductor materials as their working medium. Due to differences in material structure, the specific processes by which different types of lasers generate lasers are quite unique. VCSELs, short for Vertical Cavity Surface Emitting Lasers, offer advantages such as vertically emitted circular low-divergence beams, ease of integration into two-dimensional arrays, low power consumption, and small size; however, thermal management remains a key area for continuous optimization. Applications heavily rely on the biocompatibility and specific material absorption characteristics of 660nm red light: in the medical field, it is used for photodynamic therapy (activating tumor photosensitizers), low-intensity phototherapy (promoting wound healing), blood oxygen monitoring (light source for smart wearable devices), and fluorescence excitation in flow cytometry; industrial applications include plastic welding (matching polymer absorption peaks), fluorescence sensing, and machine vision lighting; in display technology, it serves as a red light source for laser projection and AR / VR; furthermore, it holds potential in atomic sensing (such as rubidium atom pumping). This technology has already been commercialized by companies such as Trumpf and Osram, driving the development of portable medical devices, new displays, and precision machining. The core technological breakthrough of 660nm VCSELs lies in overcoming the inherent challenges of the traditional AlGaInP material system. The technical difficulties are concentrated in material growth and structural design: AlGaInP quantum wells require precise control to achieve red light emission, but the material has low internal quantum efficiency, carriers easily overflow, and there is a lattice mismatch (approximately 0.3%) between the quantum well (InGaP / AlGaInP) and the GaAs substrate, causing the well layer to experience biaxial compressive strain. Furthermore, the existing structure leads to: ① Critical thickness limitation (<15nm) restricts the number of quantum wells and their gain; ② Severe carrier leakage occurs at high temperatures, and the characteristic temperature T0 is low (usually <100K). ③ Increased nonradiative recombination leads to decreased slope efficiency (typical value <1.0 W / A). In the epitaxial structure of traditional VCSELs, response speed is important in traditional structures focused on data optical communication. However, when developing high-power packages for sensors, optical output and voltage efficiency are important characteristics. However, in existing traditional VCSEL structures, it is not easy to simultaneously improve both optical output and voltage efficiency.

[0003] Therefore, there is an urgent need for epitaxial structures with more perfect quantum well stress compensation designs to solve the above problems. Summary of the Invention

[0004] This invention aims to overcome the test obstruction caused by the aforementioned heat sink structure. It provides an epitaxial structure and preparation method of a strain-compensated VCSEL based on AsH3 flow rate control. By introducing AsH3 flow rate gradient control technology into the AlGaAsP barrier layer, dynamic strain compensation is achieved by precisely controlling the As / P ratio: the As composition increases from bottom to top in the barrier layer, forming a gradient tensile strain to offset the compressive strain of the well layer; and atomic interdiffusion is suppressed: a high AsH3 flow rate forms an arsenic-rich transition region at the barrier / well interface, suppressing the diffusion of P atoms into the well layer, reducing the threshold current, improving the slope efficiency, and improving the characteristic temperature.

[0005] This invention also provides a method for preparing an epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation.

[0006] The technical solution of this invention is as follows: An epitaxial structure of a strain-compensated VCSEL based on AsH3 flow regulation includes a substrate, on which a buffer layer, an N-type DBR layer, an active layer, a P-type oxide confinement layer, a P-type DBR layer, and a surface-doped GaAs layer are sequentially disposed. The N-type DBR layer comprises, from bottom to top, an N-type high-Al composition layer, an N-type Al composition transition layer, and an N-type low-Al composition layer, wherein the N-type high-Al composition layer is Al 0.92 Ga 0.08 As, N-type low-Al composition layer is Al 0.5 Ga 0.5 As, the N-type Al component transition layer is composed of Al 0.92 Ga 0.08 As linear uniformly gradually changes to Al 0.5 Ga 0.5 As; The P-type DBR layer comprises, from bottom to top, a P-type high-Al composition layer, a P-type Al composition transition layer, and a P-type low-Al composition layer. The P-type high-Al composition layer is composed of Al... 0.92 Ga 0.08 As, the low-Al composition layer of the P-type is Al 0.5 Ga 0.5 As, the transition layer of the p-type Al component is composed of Al 0.92 Ga 0.08 As linear uniformly gradually changes to Al 0.5 Ga 0.5 As; The active layer includes a quantum well layer and a quantum barrier layer. The quantum well layer and the quantum barrier layer are periodically grown to form the active layer. The quantum well layer is a GaInP quantum well layer with compressive strain, and the quantum barrier layer is an AlGaInPAs quantum well layer. The quantum barrier layer is a tensile strain layer that achieves strain compensation based on precise control of AsH3 flow rate. The quantum well layer and the quantum barrier layer are arranged alternately to form a periodic structure. The buffer layer is a GaAs layer; The P-type oxide confinement layer is an AlGaInP layer.

[0007] The thickness of the buffer layer is 0.5-0.8 μm; The N-type DBR layer has a high Al content layer thickness of 580-620 nm, an Al content transition layer thickness of 80-120 nm, and a low Al content layer thickness of 540-560 nm. The three different material layers are arranged alternately to form a periodic structure. The active layer has a thickness of 0.03 μm to 0.04 μm; The thickness of the P-type oxide confinement layer is 3000 Å; The P-type DBR layer has a P-type high Al composition layer thickness of 600 nm, a P-type Al composition transition layer thickness of 80-120 nm, and a P-type low Al composition layer thickness of 550 nm. The three different material layers are arranged alternately to form a periodic structure.

[0008] The method for fabricating an epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation includes the following steps: S1: Growth buffer layer; S2: Growth of N-type DBR layer; S3: Formation of an active layer; S4: Formation of a P-type oxide confinement layer; S5: Obtain the P-type DBR layer; S6: Forms a highly doped surface layer of GaAs.

[0009] The specific steps of step S1 are as follows: The substrate is placed in the reaction chamber of a metal-organic chemical vapor deposition (MOCVD) apparatus. The reaction chamber pressure is set to 50-60 mbar and the temperature to 700-800 °C. Simultaneously, 100-120 sccm of TMGa is introduced into the reaction chamber for 4-6 minutes to grow a buffer layer.

[0010] Step S2 specifically involves: 1) Set the reaction chamber pressure to 50 mbar and the temperature to 700℃. Simultaneously, introduce 600 sccm of AsH3, 350 sccm of TMAl, and 5 sccm of TMGa into the reaction chamber to grow Al. 0.92 Ga0.08 The As layer is an N-type high Al composition layer; By controlling the aluminum and gallium sources to change uniformly, the TMAl source is gradually varied from 350 sccm to 150 sccm to grow an N-type Al composition transition layer; then, TMAl at 150 sccm and TMGa at 30 sccm are introduced to grow Al. 0.5 Ga 0.5 The As layer is an N-type low-Al composition layer; 2) Then control the aluminum source and gallium source to change uniformly, and gradually change TMAl from 150 sccm to 350 sccm, alternating growth for 65-75 minutes to form 50 groups of 3-layer DBRs on the buffer layer. 3) Al 0.92 Ga 0.08 An 8 sccm layer of Si₂H₆ is introduced into the As layer to achieve a Si doping concentration of 1E⁺¹⁸ atoms / cm². 3 Al 0.5 Ga 0.5 The As layer is saturated with 25 sccm of Si₂H₆ to achieve a Si doping concentration of 3E⁺¹⁸ atoms / cm². 3 By introducing a linearly gradually varying amount of Si2H6, the doping of the N-type Al composition transition layer is completed, resulting in the N-type DBR layer.

[0011] Step S3 is as follows: AsH3 flow rate is reduced and introduced into the barrier layer, while maintaining a PH3 atmosphere and introducing 900 sccm, the quantum well layer and quantum barrier layer of the multi-quantum well active region are grown alternately. The thickness of the active region layer is 0.05 μm. The quantum well layer is GaInP, with 900 sccm of In and 35 sccm of Ga introduced. The quantum barrier layer is AlGaInPAs. Each growth of the quantum well layer and quantum barrier layer constitutes one cycle. The active layer is formed through multiple cycles. A pH 3 atmosphere was maintained at 900 sccm, with AsH 3 introduced only into the quantum barrier layer, and the flow rate was controlled to increase uniformly from 20 sccm to 40 sccm. Five growth cycles were performed, each lasting 5 minutes. The quantum well layer was GaInP, with In introduced at 900 sccm and Ga at 35 sccm. The quantum barrier layer was AlGaInPAs, with Al composition. 0.5 GaInPAs are fed with 900 sccm of In, 100 sccm of Al, and 20 sccm of Ga. The quantum barrier layer is fed with AsH3 starting at 20 sccm and gradually increasing to 40 sccm. Each growth of the quantum well layer and the quantum barrier layer constitutes one cycle. The GaInP / AlGaInPAs cycle number is 5, forming the active layer.

[0012] Step S4 is as follows: After the active layer growth is completed, the temperature of the reaction chamber is set to 700℃ and the flow of PH3 is stopped. The flow is then switched to 450 sccm of AsH3, and the flow rate of TMAl is 350 sccm. The flow rate of TMGa is 2 sccm. The growth is continued for 1 minute to form a P-type oxide confinement layer.

[0013] Step S5 is as follows: 1) Maintain the temperature at 700℃, and simultaneously introduce 600 sccm of AsH3, 350 sccm of TMAl, and 5 sccm of TMGa into the reaction chamber to grow Al. 0.92 Ga 0.08 The As layer is a P-type high Al composition layer; By controlling the aluminum and gallium sources to change uniformly, the TMAl source is uniformly and gradually changed from 350 sccm to 150 sccm to grow a P-type Al composition transition layer. Al was grown by introducing 150 sccm of TMAl and 30 sccm of TMGa. 0.5 Ga 0.5 The As layer is a p-type low Al composition layer; 2) Then control the aluminum source and gallium source to change uniformly, and TMAl gradually changes from 150 sccm to 350 sccm, alternating growth for 65 minutes to form 30 groups of 3-layer DBRs on the buffer layer. 3)Al 0.92 Ga 0.08 A layer of CBr4 with a flux of 35-45 sccm is introduced into the As layer to achieve a C doping concentration of 1E+18 atoms / cm. 3 Al 0.5 Ga 0.5 A layer of CBr4 with a flux of 75-85 sccm is introduced into the As layer to achieve a C doping concentration of 3E+18 atoms / cm. 3 By introducing a linearly gradually varying amount of CBr4, the doping of the Al composition transition layer is completed, resulting in a P-type DBR layer.

[0014] Step S6 is as follows: The reaction chamber temperature was set to 600℃ and the pressure to 50mbar. 400sccm of AsH3 and 70sccm of TMGa were introduced into the reaction chamber. The doping concentration of CBr4 was 5E+19atom / cm3. The process was continued for 1 minute to form a highly doped surface layer of GaAs.

[0015] The beneficial effects of this invention are: 1. The epitaxial structure and preparation method of strain-compensated VCSEL based on AsH3 flow rate regulation of the present invention, by introducing AsH3 flow rate gradient regulation technology into the AlGaAsP barrier layer, can precisely control the As / P ratio to achieve dynamic strain compensation, so that the As composition of the barrier layer increases from bottom to top, forming gradient tensile strain to offset the compressive strain of the well layer; by forming an arsenic-rich transition region at the barrier / well interface through high AsH3 flow rate and suppressing the diffusion of P atoms into the well layer, the interdiffusion of atoms can be suppressed; the present invention can reduce the threshold current, improve the slope efficiency, and improve the characteristic temperature. This paper addresses the shortcomings of existing technologies. While 660nm VCSELs typically employ an lGaInP / GaAs material system, the quantum well (InGaP / AlGaInP) and GaAs substrate exhibit lattice mismatch (approximately 0.3%). Traditional strain compensation techniques introduce tensile strain into the barrier layer (e.g., increasing the P composition in AlGaAsP), but this results in low high-temperature decomposition efficiency of the P source (PH3), poor composition control precision, and overcompensation can introduce dislocations, degrading crystal quality. Furthermore, it fails to address the interface blurring issue caused by As / P atomic interdiffusion. The paper also resolves the issue that in existing VCSEL epitaxial structures used for high-power sensor packaging, both light output and voltage efficiency are crucial characteristics, yet current VCSEL structures cannot simultaneously improve both.

[0016] 2. The epitaxial structure and preparation method of strain-compensated VCSEL based on AsH3 flow rate regulation of the present invention are compatible with existing production lines, requiring only adjustment of MOCVD gas flow parameters without the need for additional equipment.

[0017] 3. This invention has a dynamic gradient compensation function, and the linear change of AsH3 flow rate achieves a smooth strain transition, avoiding interface mismatch and dislocation.

[0018] 4. This invention has a dual-effect synergy, which can simultaneously solve the two major problems of strain accumulation and atomic interdiffusion.

[0019] 5. This invention uses the AsH3 / P source mass flow controller (MFC) with precision calibration (error < ±0.5 sccm) to prevent overcompensation from causing barrier layer lattice relaxation, thus reliably mitigating risks. Attached Figure Description Figure 1 This is a schematic diagram of the epitaxial structure of the strain-compensated VCSEL based on AsH3 flow regulation in Example 1. Figure 2 The process flow diagram for preparing the VCSEL epitaxial structure in Example 1 is shown.

[0020] Figure 3 This is a schematic diagram showing the amount of V-group source used in the active layer of the VCSEL epitaxial structure in Example 1.

[0021] Figure 4 This is a schematic diagram showing the amount of V-group source in the active layer of the VCSEL epitaxial structure in Comparative Example 1.

[0022] In the figure, 1 is the substrate, 2 is the buffer layer, 3 is the N-type high Al content layer, 4 is the N-type Al content transition layer, 5 is the N-type low Al content layer, 6 is the active layer with strain compensation, 7 is the P-type oxide confinement layer, 8 is the P-type high Al content layer, 9 is the P-type Al content transition layer, 10 is the P-type low Al content layer, and 11 is the surface highly doped layer. Detailed Implementation The present invention will be further described below with reference to embodiments and accompanying drawings, but is not limited thereto.

[0023] Example 1 An epitaxial structure of a strain-compensated VCSEL based on AsH3 flow regulation, combined with Figure 1 The substrate includes a substrate 1, on which a buffer layer 2, an N-type DBR layer, an active layer 6 with strain compensation, a P-type oxide confinement layer 7, a P-type DBR layer, and a highly doped surface layer 11 GaAs are sequentially disposed. The N-type DBR layer includes, from bottom to top, an N-type high Al composition layer 3, an N-type Al composition transition layer 4, and an N-type low Al composition layer 5. The high Al composition layer is Al0.92Ga0.08As, the low Al composition layer is Al0.5Ga0.5As, and the Al composition transition layer is linearly and uniformly changed from Al0.92Ga0.08As to Al0.5Ga0.5As. The P-type DBR layer includes, from bottom to top, a P-type high Al composition layer 8, a P-type Al composition transition layer 9, and a P-type low Al composition layer 10. The high Al composition layer is Al0.92Ga0.08As, the low Al composition layer is Al0.5Ga0.5As, and the Al composition transition layer is linearly and uniformly gradiented from Al0.92Ga0.08As to Al0.5Ga0.5As. The active layer includes a quantum well layer and a quantum barrier layer. The quantum well layer and the quantum barrier layer are periodically grown to form the active layer. The quantum well layer is a GaInP quantum well layer with compressive strain, and the quantum barrier layer is AlGaInPAs. The quantum barrier layer is a tensile strain layer that achieves strain compensation based on precise control of AsH3 flow rate. The quantum well layer and the quantum barrier layer are arranged alternately to form a periodic structure. One quantum well layer and one quantum barrier layer constitute one period, and the number of periods is 5. The thickness of the active layer is 0.03μm-0.04μm.

[0024] The N-type DBR layer has a thickness of 580-620 nm for the N-type high-Al content layer, a thickness of 80-120 nm for the N-type Al content transition layer, and a thickness of 540-560 nm for the N-type low-Al content layer. The three different material layers are arranged alternately in an ABCABC pattern to form a periodic structure.

[0025] The number of cycles in the N-type DBR layer arrangement is 50-55.

[0026] In this invention, the N-type DBR layer improves the external quantum efficiency to 99.9%. Too much of it will affect the cost, while too little will reduce the reflection efficiency.

[0027] The buffer layer is a GaAs layer with a thickness of 0.5-0.8 μm.

[0028] The P-type oxide confinement layer is an AlGaInP layer with a thickness of 3000 Å.

[0029] The P-type DBR layer has a P-type high Al composition layer thickness of 600 nm, a P-type Al composition transition layer thickness of 80-120 nm, and a P-type low Al composition layer thickness of 550 nm. The three different material layers are arranged alternately in an ABCABC pattern to form a periodic structure with a period number of 30-35.

[0030] Example 2 A method for fabricating epitaxial structures of strain-compensated VCSELs based on AsH3 flow rate regulation, such as Figure 2 As shown, it includes the following steps: S1: Place the substrate into the reaction chamber of the metal-organic chemical vapor deposition equipment, set the reaction chamber pressure to 50 mbar and the temperature to 700 °C, and simultaneously introduce 100 sccm of trimethylgallium (TMGa) into the reaction chamber for 4 minutes to grow a buffer layer. In step S1, the specific steps for growing the buffer layer are as follows: Set the reaction chamber pressure to 50-60 mbar and the temperature to 700-800℃, while simultaneously introducing 100-120 sccm of trimethylgallium (TMGa) into the reaction chamber for 4-6 minutes to grow a buffer layer.

[0031] S2: Growth of N-type DBR layer, the specific steps are as follows: 1) Set the reaction chamber pressure to 50 mbar and the temperature to 700℃. Simultaneously, introduce 600 sccm of AsH3, 350 sccm of trimethylaluminum (TMAl), and 5 sccm of trimethylgallium (TMGa) into the reaction chamber to grow an Al0.92Ga0.08As layer, which is an N-type high Al composition layer. By controlling the aluminum and gallium sources to change uniformly, TMAl is uniformly and gradually changed from 350 sccm to 150 sccm to grow an N-type Al composition transition layer; TMAl at 150 sccm and TMGa at 30 sccm are introduced to grow an Al0.5Ga0.5As layer, which is an N-type low Al composition layer. 2) Then control the aluminum source and gallium source to change uniformly, and gradually change TMAl from 150 sccm to 350 sccm, alternating growth for 65-75 minutes to form 50 groups of 3-layer DBRs on the buffer layer. 3) Al 0.92 Ga 0.08 An 8 sccm layer of Si₂H₆ is introduced into the As layer to achieve a Si doping concentration of 1E⁺¹⁸ atoms / cm². 3 Al 0.5 Ga 0.5 The As layer is saturated with 25 sccm of Si₂H₆ to achieve a Si doping concentration of 3E⁺¹⁸ atoms / cm². 3 By introducing a linearly gradually varying amount of Si2H6, the doping of the N-type Al composition transition layer is completed, resulting in an N-type DBR layer. S3: Forming the active layer, the specific steps are as follows: AsH3 flow rate is reduced and introduced into the barrier layer, while maintaining a PH3 atmosphere and introducing 900 sccm, the quantum well layer and quantum barrier layer of the multi-quantum well active region are grown alternately. The thickness of the active region layer is 0.05 μm. The quantum well layer is GaInP, with 900 sccm of In and 35 sccm of Ga introduced. The quantum barrier layer is AlGaInPAs. Each growth of the quantum well layer and quantum barrier layer constitutes one cycle. The active layer is formed through multiple cycles. A PH3 atmosphere is maintained at 900 sccm, and AsH3 is only introduced into the quantum barrier layer, with the flow rate controlled to increase uniformly from 20 sccm to 40 sccm. Five growth cycles are performed, each lasting 5 minutes. The quantum well layer is GaInP, requiring 900 sccm of In and 35 sccm of Ga. The quantum barrier layer is AlGaInPAs, with a composition of Al0.5GaInPAs, requiring 900 sccm of In, 100 sccm of Al, and 20 sccm of Ga. Most importantly, the quantum barrier layer is introduced with AsH3 at a starting flow rate of 20 sccm, which is then uniformly increased to 40 sccm. Each growth of the quantum well layer and the quantum barrier layer constitutes one cycle. The number of cycles for GaInP / AlGaInPAs is 5, forming the active layer. S4: Formation of a P-type oxide confinement layer, the specific steps are as follows: After the active layer growth is completed, the temperature of the reaction chamber is set to 700℃ and the PH3 flow is stopped. The flow rate is switched to 450 sccm of AsH3, and the flow rate of TMAl is 350 sccm. The flow rate of TMGa is 2 sccm. The growth is continued for 1 minute to form a P-type oxide confinement layer. S5: Obtain the P-type DBR layer. The specific steps are as follows: 1) The temperature is maintained at 700℃, and 600 sccm of AsH3, 350 sccm of trimethylaluminum (TMAl) and 5 sccm of trimethylgallium (TMGa) are introduced into the reaction chamber to grow an Al0.92Ga0.08As layer, which is a P-type high Al composition layer. By controlling the aluminum and gallium sources to change uniformly, the TMAl source is uniformly and gradually changed from 350 sccm to 150 sccm to grow a P-type Al composition transition layer. Al was grown by introducing 150 sccm of TMAl and 30 sccm of TMGa. 0.5 Ga 0.5 The As layer is a p-type low Al composition layer; 2) Then control the aluminum source and gallium source to change uniformly, and TMAl gradually changes from 150 sccm to 350 sccm, alternating growth for 65 minutes to form 30 groups of 3-layer DBRs on the buffer layer. 3)Al 0.92 Ga 0.08 A layer of CBr4 with a flux of 35-45 sccm is introduced into the As layer to achieve a C doping concentration of 1E+18 atoms / cm. 3 Al 0.5 Ga 0.5 A layer of CBr4 with a flux of 75-85 sccm is introduced into the As layer to achieve a C doping concentration of 3E+18 atoms / cm. 3 By introducing a linearly gradually varying amount of CBr4, the doping of the P-type Al composition transition layer is completed, thus obtaining the P-type DBR layer. S6: Forming a highly doped surface layer of GaAs, the specific steps are as follows: The reaction chamber temperature was set to 600℃ and the pressure to 50mbar. 400sccm of AsH3 and 70sccm of TMGa were introduced into the reaction chamber. The doping concentration of CBr4 was 5E+19atom / cm3. The process was continued for 1 minute to form a highly doped surface layer of GaAs.

[0032] Comparative Example 1 The existing vertical-cavity surface-emitting laser (VCSEL) epitaxial structure employs the following approach: no strain compensation optimization is performed in the active region; a PH3 atmosphere is maintained at 900 sccm throughout the S3 phase, while AsH3 is shut off; the well layer is GaInP, requiring a 900 sccm In and 35 sccm Ga atmosphere; the barrier layer is AlGaInPAs, with an Al composition. 0.5 GaInPAs only require 900 sccm of In, 100 sccm of Al, and 20 sccm of Ga; each growth of the well and barrier layers constitutes one cycle, and the number of cycles for GaInP / AlGaInPAs is 5; thus forming an active layer. Therefore, this differs from the epitaxial structure of Embodiment 1 of this invention. Figure 3 , Figure 4 As shown.

[0033] Experimental comparison In Example 1 and Comparative Example 1, three samples were used respectively to conduct comparative tests on various performance parameters under a certain operating current. The test results are shown in Table 1: Table 1

[0034] Experimental conclusions This invention achieves precise strain compensation in the barrier layer of a 660nm VCSEL by controlling the AsH3 flux gradient, overcoming the lattice mismatch limitation of traditional AlGaInP quantum wells. Experiments have confirmed that this scheme can improve slope efficiency by 100% and characteristic temperature by 94%, providing a feasible mass production path for high-power visible light VCSELs.

[0035] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

[0036] Furthermore, it is understood that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

Claims

1. An epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation, comprising a substrate, characterized in that, The substrate is sequentially provided with a buffer layer, an N-type DBR layer, an active layer, a P-type oxide confinement layer, a P-type DBR layer, and a surface-highly doped GaAs layer. The N-type DBR layer comprises, from bottom to top, an N-type high-Al composition layer, an N-type Al composition transition layer, and an N-type low-Al composition layer, wherein the N-type high-Al composition layer is Al 0.92 Ga 0.08 As, N-type low-Al composition layer is Al 0.5 Ga 0.5 As, the N-type Al component transition layer is composed of Al 0.92 Ga 0.08 As linear uniformly gradually changes to Al 0.5 Ga 0.5 As; The P-type DBR layer comprises, from bottom to top, a P-type high-Al composition layer, a P-type Al composition transition layer, and a P-type low-Al composition layer. The P-type high-Al composition layer is composed of Al... 0.92 Ga 0.08 As, the low-Al composition layer of the P-type is Al 0.5 Ga 0.5 As, the transition layer of the p-type Al component is composed of Al 0.92 Ga 0.08 As linear uniformly gradually changes to Al 0.5 Ga 0.5 As; The active layer includes a quantum well layer and a quantum barrier layer. The quantum well layer and the quantum barrier layer are periodically grown to form the active layer. The quantum well layer is a GaInP quantum well layer with compressive strain, and the quantum barrier layer is an AlGaInPAs quantum well layer. The quantum barrier layer is a tensile strain layer that achieves strain compensation based on precise control of AsH3 flow rate. The quantum well layer and the quantum barrier layer are arranged alternately to form a periodic structure. The buffer layer is a GaAs layer; The P-type oxide confinement layer is an AlGaInP layer.

2. The epitaxial structure of the strain-compensated VCSEL based on AsH3 flow regulation according to claim 1, characterized in that, The thickness of the buffer layer is 0.5-0.8 μm; The N-type DBR layer has a high Al content layer thickness of 580-620 nm, an Al content transition layer thickness of 80-120 nm, and a low Al content layer thickness of 540-560 nm. The three different material layers are arranged alternately to form a periodic structure. The active layer has a thickness of 0.03 μm to 0.04 μm; The thickness of the P-type oxide confinement layer is 3000 Å; The P-type DBR layer has a P-type high Al composition layer thickness of 600 nm, a P-type Al composition transition layer thickness of 80-120 nm, and a P-type low Al composition layer thickness of 550 nm. The three different material layers are arranged alternately to form a periodic structure.

3. The method for fabricating the epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation as described in claim 2, characterized in that, Includes the following steps: S1: Growth buffer layer; S2: Growth of N-type DBR layer; S3: Formation of an active layer; S4: Formation of a P-type oxide confinement layer; S5: Obtain the P-type DBR layer; S6: Forms a highly doped surface layer of GaAs.

4. The method for fabricating the epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation as described in claim 3, characterized in that, The specific steps of step S1 are as follows: The substrate is placed in the reaction chamber of a metal-organic chemical vapor deposition (MOCVD) apparatus. The reaction chamber pressure is set to 50-60 mbar and the temperature to 700-800 °C. Simultaneously, 100-120 sccm of TMGa is introduced into the reaction chamber for 4-6 minutes to grow a buffer layer.

5. The method for fabricating the epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation as described in claim 3, characterized in that, Step S2 specifically involves: 1) Set the reaction chamber pressure to 50 mbar and the temperature to 700℃. Simultaneously, introduce 600 sccm of AsH3, 350 sccm of TMAl, and 5 sccm of TMGa into the reaction chamber to grow Al. 0.92 Ga 0.08 The As layer is an N-type high Al composition layer; By controlling the aluminum and gallium sources to change uniformly, the TMAl source is uniformly and gradually changed from 350 sccm to 150 sccm to grow an N-type Al composition transition layer. Al was grown by introducing 150 sccm of TMAl and 30 sccm of TMGa. 0.5 Ga 0.5 The As layer is an N-type low-Al composition layer; 2) Then control the aluminum source and gallium source to change uniformly, and gradually change TMAl from 150 sccm to 350 sccm, alternating growth for 65-75 minutes to form 50 groups of 3-layer DBRs on the buffer layer. 3) Al 0.92 Ga 0.08 An 8 sccm layer of Si₂H₆ is introduced into the As layer to achieve a Si doping concentration of 1E⁺¹⁸ atoms / cm². 3 Al 0.5 Ga 0.5 The As layer is saturated with 25 sccm of Si₂H₆ to achieve a Si doping concentration of 3E⁺¹⁸ atoms / cm². 3 By introducing a linearly gradually varying amount of Si2H6, the doping of the N-type Al composition transition layer is completed, resulting in the N-type DBR layer.

6. The method for fabricating the epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation as described in claim 3, characterized in that, Step S3 is as follows: AsH3 flow rate is reduced and introduced into the barrier layer, while maintaining a PH3 atmosphere and introducing 900 sccm, the quantum well layer and quantum barrier layer of the multi-quantum well active region are grown alternately. The thickness of the active region layer is 0.05 μm. The quantum well layer is GaInP, with 900 sccm of In and 35 sccm of Ga introduced. The quantum barrier layer is AlGaInPAs. Each growth of the quantum well layer and quantum barrier layer constitutes one cycle. The active layer is formed through multiple cycles. A pH 3 atmosphere was maintained at 900 sccm, with AsH 3 introduced only into the quantum barrier layer, and the flow rate was controlled to increase uniformly from 20 sccm to 40 sccm. Five growth cycles were performed, each lasting 5 minutes. The quantum well layer was GaInP, with In introduced at 900 sccm and Ga at 35 sccm. The quantum barrier layer was AlGaInPAs, with Al composition. 0.5 GaInPAs are fed with 900 sccm of In, 100 sccm of Al, and 20 sccm of Ga. The quantum barrier layer is fed with AsH3 starting at 20 sccm and gradually increasing to 40 sccm. Each growth of the quantum well layer and the quantum barrier layer constitutes one cycle. The GaInP / AlGaInPAs cycle number is 5, forming the active layer.

7. The method for fabricating the epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation as described in claim 3, characterized in that, Step S4 is as follows: After the active layer growth is completed, the temperature of the reaction chamber is set to 700℃ and the flow of PH3 is stopped. The flow is then switched to 450 sccm of AsH3, and the flow rate of TMAl is 350 sccm. The flow rate of TMGa is 2 sccm. The growth is continued for 1 minute to form a P-type oxide confinement layer.

8. The method for fabricating the epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation as described in claim 3, characterized in that, Step S5 is as follows: 1) Maintain the temperature at 700℃, and simultaneously introduce 600 sccm of AsH3, 350 sccm of TMAl, and 5 sccm of TMGa into the reaction chamber to grow Al. 0.92 Ga 0.08 The As layer is a P-type high Al composition layer; By controlling the aluminum and gallium sources to change uniformly, the TMAl source is uniformly and gradually changed from 350 sccm to 150 sccm to grow a P-type Al composition transition layer. Al was grown by introducing 150 sccm of TMAl and 30 sccm of TMGa. 0.5 Ga 0.5 The As layer is a p-type low Al composition layer; 2) Then control the aluminum source and gallium source to change uniformly, and TMAl gradually changes from 150 sccm to 350 sccm, alternating growth for 65 minutes to form 30 groups of 3-layer DBRs on the buffer layer. 3)Al 0.92 Ga 0.08 A layer of CBr4 with a flux of 35-45 sccm is introduced into the As layer to achieve a C doping concentration of 1E+18 atoms / cm. 3 Al 0.5 Ga 0.5 A layer of CBr4 with a flux of 75-85 sccm is introduced into the As layer to achieve a C doping concentration of 3E+18 atoms / cm. 3 By introducing a linearly gradually varying amount of CBr4, the doping of the Al composition transition layer is completed, resulting in a P-type DBR layer.

9. The method for fabricating the epitaxial structure of a strain-compensated VCSEL based on AsH3 flow rate regulation as described in claim 3, characterized in that, Step S6 is as follows: The reaction chamber temperature was set to 600℃ and the pressure to 50mbar. 400sccm of AsH3 and 70sccm of TMGa were introduced into the reaction chamber. The doping concentration of CBr4 was 5E+19atom / cm3. The process was continued for 1 minute to form a highly doped surface layer of GaAs.

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