Asymmetric hetero waveguide 808 nm semiconductor laser structure and preparation method thereof

Abstract

The application relates to an asymmetric semiconductor laser structure; a conventional n-p side waveguide layer adopts a homogenous semiconductor, the energy band structure between the waveguide layer and the confinement layer is relatively fixed, loss in a carrier transport process is caused, and working voltage and output power are affected, the application provides an asymmetric hetero waveguide 808nm semiconductor laser structure and a preparation method thereof; the asymmetric hetero waveguide structure can regulate and control light field distribution, reduces light loss, and can also optimize carrier transport capacity, can solve the problems of serious carrier light absorption loss in an epitaxial structure and large energy loss in a transport process, reduces light loss and leakage current in working, reduces series resistance and working voltage, and improves the output power and electro-optical conversion efficiency of the laser.

Description

Technical Field

[0001] This invention relates to asymmetric semiconductor laser structures, and more specifically, to an asymmetric heterostructure waveguide 808nm semiconductor laser structure and its fabrication method. Background Technology

[0002] The waveguide layer is a crucial component of an 808 nm semiconductor laser, playing a key role in its output characteristics. Waveguide structures typically employ asymmetric waveguides, with optical losses reduced by adjusting the waveguide thickness. However, conventional np-side waveguide layers usually utilize homogeneous semiconductors, resulting in a relatively fixed band structure between the waveguide and confinement layers. This can lead to losses in carrier transport, affecting operating voltage and output power. In fact, the band structure is closely related to operating voltage and series resistance; therefore, optimizing the epitaxial structure to reduce n-side energy loss is extremely important.

[0003] High carrier loss and high operating voltage leading to high energy loss are key scientific problems affecting the high power and high electro-optical conversion efficiency output of 808 nm semiconductor lasers. Traditional waveguides use homogeneous AlGaAs material on both the n and p sides, with relatively fixed band structures between epitaxial layers. Asymmetric waveguide structures optimize the optical field distribution by adjusting the thickness of the n-type and p-type waveguides to reduce optical loss, considering only the electrical and thermal conductivity of each layer. Furthermore, carrier loss during transmission increases the operating voltage of the 808 nm semiconductor laser, reducing its electro-optical conversion efficiency. This is a major factor limiting the high performance of 808 nm semiconductor lasers. The InGaAsP material system provides a smaller conduction band gap and a larger valence band gap, which is beneficial for electron injection in the conduction band and the formation of a higher potential barrier for holes in the valence band. Using an asymmetric heterogeneous waveguide structure with n-type InGaAsP and p-type AlGaAs, electrons and holes are confined separately, thereby reducing the voltage drop and improving the injection efficiency and output power. Therefore, designing asymmetric heterostructure waveguides for high-power semiconductor lasers is of great significance for reducing carrier loss and improving the electrical performance of semiconductor lasers. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an asymmetric heterostructure waveguide 808nm semiconductor laser structure and its fabrication method. This invention can not only control the optical field distribution and reduce optical loss, but also optimize carrier transport capability and reduce interface carrier loss, thereby reducing series resistance and operating voltage, and achieving the goal of improving output power and electro-optical conversion efficiency.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An asymmetric heteroguide 808nm semiconductor laser structure includes an n-GaAs substrate and n-In atoms arranged sequentially along the epitaxial growth direction. x Ga 1-x As 1-y Py confinement layer, n-In x Ga 1-x As 1-y P y waveguide layer, n-In x Ga 1-x As 1-y P y Barrier layer, In x Ga 1-x As 1-y P y Quantum well layer, p-GaAs 1-x P x Barrier layer, p-Al x Ga 1-x As waveguide layer, p-Al x Ga 1-x As confinement layer, p-GaAs contact layer, wherein: n-GaAs substrate is grown on the crystal plane, n-In x Ga 1-x As 1-y P y The confinement layer is grown on an n-GaAs substrate; n-In x Ga 1-x As 1-y P y waveguide layer in n-In x Ga 1-x As 1-y P y Growth on confinement layers; n-In x Ga 1-x As 1-y P y Barrier layer in n-In x Ga 1-x As 1-y P y Growth on waveguide layer, In x Ga 1-x As 1-y P y Quantum well layers in n-Ga 1-x In x As 1-y P y Growth on barrier layer; p-GaAs 1-x P x Barrier layer in In x Ga 1-x As 1-y Py Growth on quantum well layers; p-Al x Ga 1-x As waveguide layer in p-GaAs 1-x P x Growth on barrier layer; p-Al x Ga 1-x As confinement layer in p-Al x Ga 1-x p-GaAs waveguide layer grown on p-Al; p-GaAs contact layer grown on p-Al x Ga 1-x Growth on As confinement layer.

[0006] Furthermore, the thickness of the n-GaAs substrate is 1000~3000 nm, and the doping concentration of the n-GaAs substrate is 5×10⁻⁶. 18 ~1×10 19 cm -3 The thickness of the p-GaAs contact layer is 100~500nm, and the constant doping concentration of the p-GaAs contact layer is 5×10⁻⁶. 19 ~1×10 20 cm -3 .

[0007] Furthermore, In x Ga 1-x As 1-y P y The quantum well layer thickness is 3~10 nm, the In composition satisfies 0 < x < 0.10, and the P composition satisfies 0 < y < 0.15. x Ga 1-x As 1-y P y The quantum well layer is undoped.

[0008] Furthermore, n-Ga 1-x In x As 1-y P y The barrier layer thickness is 10~20 nm, with In composition satisfying 0.4 < x < 0.55 and P composition satisfying 0.8 < y < 0.95; p-GaAs 1-x P x Barrier layer thickness and n-Ga 1-x In x As 1-y P y With the same barrier layer thickness, the P composition satisfies 0.2 < x < 0.7; n-Ga 1-x In x As 1-y P y Barrier layer and p-GaAs 1-x P x The barrier layers are all undoped.

[0009] Furthermore, n-In x Ga 1-x As 1-y P y The waveguide layer thickness is 300~700nm, with In and P components gradually varying. The maximum value of the In component is related to n-In. x Ga 1-x As 1-y P y The In components in the confined layer are identical, and the minimum In component value is greater than 0; n-In x Ga 1-x As 1-y P y The waveguide layer has a gradually changing doping concentration, with the maximum doping concentration being less than n-In. x Ga 1-x As 1-y P y Doping concentration of the confinement layer; p-Al x Ga 1-x The thickness of the As waveguide layer is 300~700nm, and the Al composition gradually changes. The maximum value of the Al composition is related to p-Al. x Ga 1-x The Al composition in the As confinement layer is the same, and the minimum Al composition value is greater than 0; p-Al x Ga 1-x The doping concentration of the As waveguide layer gradually changes, and the maximum doping concentration is less than that of p-Al. x Ga 1-x As confinement layer doping concentration.

[0010] Furthermore, n-In x Ga 1-x As 1-y P y The confinement layer thickness is 1000~1500nm, and the doping concentration is the same as that of the n-GaAs substrate, n-In x Ga 1-x As 1-y P y In the confinement layer, the In component x satisfies 0.4 < x < 0.55, and the P component satisfies 0.8 < y < 0.95. With In and P components fixed, n-In... x Ga 1-x As 1-y P y The In and P components in the confinement layer are respectively related to n-In x Ga 1-x As 1-y P y The maximum values ​​of the In and P components in the waveguide layer are the same; p-Al x Ga 1-xThe As confinement layer thickness is 1000~1500nm, and the doping concentration is the same as that of the p-GaAs contact layer. x Ga 1-x In the As confinement layer, the Al component satisfies 0.4 < x < 0.6, the Al component is fixed, and it is related to p-Al x Ga 1-x The maximum values ​​of the Al component are the same in the As waveguide layer; n-In x Ga 1-x As 1-y P y Confinement layer and p-Al x Ga 1-x The doping concentration of the As confinement layer is fixed.

[0011] A method for fabricating an asymmetric heterostructure waveguide 808nm semiconductor laser structure, based on the above-mentioned asymmetric heterostructure waveguide 808nm semiconductor laser structure, specifically includes the following steps: Step 1. Clean the n-GaAs substrate surface with an off-angle: Introduce hydrogen gas and keep the reaction chamber temperature at 700-740 ℃ for 5-15 minutes to clean off particulate contaminants on the n-GaAs substrate surface and remove oxygen atoms from the n-GaAs substrate surface. Step 2. n-In x Ga 1-x As 1-y Py confinement layer growth: The reaction chamber temperature was reduced to 650-680 °C, the trimethylgallium flow rate was 45 sccm, the arsine flow rate was 800-1500 sccm, the phosphine flow rate was 300-500 sccm, and the trimethylindium flow rate was 240 sccm, to grow n-In on an n-GaAs substrate. x Ga 1-x As 1-y Py confinement layer; n-type doping concentration is 1×10⁻⁶ 19 cm -3 ; Step 3. n-In x Ga 1-x As 1-y P y Waveguide layer growth: The reaction chamber temperature was kept constant, the flow rate of trimethylgallium was 45 sccm, the flow rate of arsine was 800–1500 sccm, the flow rate of phosphine was 300–500 sccm, and the flow rate of trimethylindium was 240 sccm, in n-In x Ga 1-x As 1-y n-In grown on Py confinement layer x Ga 1-x As 1-y P yWaveguide layer; n-type doping concentration is 1×10 17 ~1×10 18 cm -3 ; Step 4. n-In x Ga 1-x As 1-y P y Barrier layer growth: The reaction chamber temperature was kept constant, the flow rate of trimethylgallium was 45 sccm, the flow rate of arsine was 800–1500 sccm, the flow rate of phosphine was 300–500 sccm, and the flow rate of trimethylindium was 240 sccm, in n-In x Ga 1-x As 1-y P y n-In grown on waveguide layer x Ga 1-x As 1-y P y Barrier layer; Step 5. In x Ga 1-x As 1-y P y Quantum well layer growth: The reaction chamber temperature was reduced to 550–650 °C, the trimethylgallium flow rate was 90 sccm, and the arsine flow rate was 440 sccm, in n-In x Ga 1-x As 1-y P y In growing on the barrier layer x Ga 1-x As 1-y P y Quantum well layer; Step 6. p-GaAs 1-x P x Barrier layer growth: The reaction chamber temperature is raised to 650–680 °C, the trimethylgallium flow rate is 45 sccm, the arsine flow rate is 800–1500 sccm, the phosphine flow rate is 300–500 sccm, and In… x Ga 1-x As 1-y P y p-GaAs grown on quantum well layers 1-x P x Barrier layer; Step 7. p-Al x Ga 1-x As waveguide layer growth: The reaction chamber temperature was kept constant, the flux density was 97 sccm for trimethylgallium, 28 sccm for trimethylaluminum, 1160 sccm for arsine, and 5-20 sccm for carbon tetrabromide, in p-GaAs... 1-x P x p-Al growing on barrier layer x Ga 1-x As waveguide layer, p-type doping concentration is 1×10⁻⁶ 17 ~1×10 18 cm -3 ; Step 8. p-Al x Ga 1-x As confinement layer growth: The reaction chamber temperature was kept constant, the flow rate of trimethylgallium was 75 sccm, the flow rate of trimethylaluminum was 70 sccm, the flow rate of arsine was 1160 sccm, and the flow rate of carbon tetrabromide was 5~20 sccm, in p-Al x Ga 1- x p-Al grown on As waveguide layer x Ga 1-x As confinement layer, p-type doping concentration 1×10 19 cm -3 ; Step 9. p-GaAs contact layer growth: The reaction chamber temperature remains constant, the trimethylgallium flow rate is 90 sccm, the arsine flow rate is 440 sccm, and the carbon tetrabromide flow rate is 10~25 sccm. In the p-Al... x Ga 1-x p-GaAs contact layers are grown on the As confinement layer.

[0012] Furthermore, the offset angle of the n-GaAs substrate is 0 to 1°.

[0013] In summary, the invention has the following beneficial effects: The asymmetric heterogeneous waveguide structure of this invention can modulate the optical field distribution, reduce optical loss, optimize carrier transport capability, and reduce interface carrier loss, thereby reducing series resistance and operating voltage, and achieving the goal of improving output power and electro-optical conversion efficiency. This invention solves the problems of severe carrier optical absorption loss and large energy loss during transport in epitaxial structures, reducing optical loss and leakage current during operation, thereby reducing the series resistance and operating voltage of the laser, and improving the laser's output power and electro-optical conversion efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the semiconductor laser of the present invention; Figure 2 This is a schematic diagram of the energy band structure along the epitaxial direction of the asymmetric heterostructure waveguide of the 808 nm semiconductor laser of the present invention. Figure 3 The diagram shows the IV curves of a traditional asymmetric waveguide structure and the asymmetric heterogeneous waveguide 808 nm semiconductor laser of this invention.

[0015] In the figure: 1. n-GaAs substrate, 2. n-In x Ga 1-x As 1-y Py confinement layers, 3, n-In x Ga 1-x As 1-y P y Waveguide layer, 4, n-In x Ga 1-x As 1-y P y Barrier layer, 5, In x Ga 1-x As 1-y P y Quantum well layer, 6, p-GaAs 1-x P x Barrier layer, 7, p-Al x Ga 1-x As waveguide layer, 8, p-Al x Ga 1-x As confinement layer, 9. p-GaAs contact layer. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings.

[0017] It should be noted that, for ease of description, the descriptions of direction in the following text are consistent with the directions in the accompanying drawings, but they do not limit the structure of the present invention.

[0018] like Figures 1-3 As shown, this invention discloses an asymmetric heteroguide 808nm semiconductor laser structure, in which InGaAsP serves as the n-type waveguide layer and confinement layer, and AlGaAs serves as the p-type waveguide layer and confinement layer. The key feature of this structure is that, without altering the active region, it can improve carrier confinement capability, reducing carrier loss and leakage throughout the epitaxial structure, thereby lowering the operating voltage and series resistance, and improving output power and electro-optic conversion efficiency. The structure includes an n-GaAs substrate 1 and n-InGaAs layers sequentially arranged along the epitaxial growth direction. x Ga 1-x As 1-y Py confinement layer 2, n-In x Ga 1-x As 1-y P y Waveguide layer 3, n-In x Ga 1- x As 1-y P y Barrier layer 4, In x Ga1-x As 1-y P y Quantum well layer 5, p-GaAs 1-x P x Barrier layer 6, p-Al x Ga 1-x As waveguide layer 7, p-Al x Ga 1-x As confinement layer 8, p-GaAs contact layer 9, wherein: n-GaAs substrate 1 is grown on a crystal plane, with a thickness of 1000~3000 nm and a doping concentration of 5×10⁻⁶. 18 ~1×10 19 cm -3 ;n-In x Ga 1-x As 1-y P y Confinement layer 2 is grown on n-GaAs substrate 1, n-In x Ga 1- x As 1-y P y The confinement layer 2 has a thickness of 1000~1500 nm and a doping concentration the same as that of the n-GaAs substrate 1, and n-In x Ga 1-x As 1-y P y In confinement layer 2, the In component x satisfies 0.4 < x < 0.55, and the P component satisfies 0.8 < y < 0.95. With In and P components fixed, n-In... x Ga 1- x As 1-y P y The In and P components in confinement layer 2 are respectively related to n-In x Ga 1-x As 1-y P y In waveguide layer 3, the maximum values ​​of the In and P components are the same; n-In x Ga 1-x As 1-y P y Waveguide layer 3 in n-In x Ga 1-x As 1-y P y Growth on confinement layer 2, n-In x Ga 1-x As 1-y P y Waveguide layer 3 has a thickness of 300~700nm, with In and P components that are gradually varied. The maximum value of the In component is related to n-In.x Ga 1-x As 1-y P y The In component in confinement layer 2 is the same, and the minimum In component value is greater than 0; n-In x Ga 1-x As 1-y P y Waveguide layer 3 has a gradually changing doping concentration, with the maximum doping concentration being less than n-In. x Ga 1-x As 1-y P y Doping concentration of confinement layer 2; n-In x Ga 1-x As 1-y P y Barrier layer 4 in n-In x Ga 1-x As 1-y P y n-Ga grown on waveguide layer 3 1-x In x As 1-y P y The barrier layer 4 has a thickness of 10-20 nm, with In composition satisfying 0.4 < x < 0.55 and P composition satisfying 0.8 < y < 0.95; In x Ga 1-x As 1-y P y Quantum well layer 5 in n-Ga 1-x In x As 1-y P y Growth on barrier layer 4, In x Ga 1-x As 1-y P y The quantum well layer 5 has a thickness of 3-10 nm, with In composition satisfying 0 < x < 0.10 and P composition satisfying 0 < y < 0.15. x Ga 1-x As 1-y P y Quantum well layer 5 is undoped; p-GaAs 1-x P x Barrier layer 6 in In x Ga 1-x As 1-y P y p-GaAs grown on quantum well layer 5 1-x P x The thickness of barrier layer 6 and n-Ga 1-x In x As 1-y P yThe barrier layer 4 has the same thickness, and the P composition satisfies 0.2 < x < 0.7; n-Ga 1-x In x As 1-y P y Barrier layer 4 and p-GaAs 1-x P x Barrier layer 6 is undoped; p-Al x Ga 1-x As waveguide layer 7 in p-GaAs 1-x P x p-Al grows on barrier layer 6 x Ga 1-x The thickness of the As waveguide layer 7 is 300~700nm, and the Al composition gradually changes. The maximum value of the Al composition is related to p-Al. x Ga 1-x The Al composition in As confinement layer 8 is the same, and the minimum Al composition value is greater than 0; p-Al x Ga 1-x The doping concentration of As waveguide layer 7 gradually changes, with the maximum doping concentration being less than that of p-Al. x Ga 1-x As confinement layer 8 doping concentration; p-Al x Ga 1-x As confinement layer 8 in p-Al x Ga 1-x p-Al grown on As waveguide layer 7 x Ga 1-x The As confinement layer 8 has a thickness of 1000~1500 nm and a doping concentration similar to that of the p-GaAs contact layer 9. The p-Al... x Ga 1-x In As confinement layer 8, the Al component satisfies 0.4 < x < 0.6, the Al component is fixed, and it is related to p-Al x Ga 1-x The maximum values ​​of the Al component are the same in waveguide layer 7, n-In x Ga 1-x As 1-y P y Confinement layer 2 and p-Al x Ga 1-x The doping concentration of As confinement layer 8 is fixed; p-GaAs contact layer 9 is in p-Al x Ga 1-x The p-GaAs contact layer 9, grown on the As confinement layer 8, has a thickness of 100–500 nm and a constant doping concentration of 5 × 10⁻⁶. 19 ~1×10 20 cm -3 .

[0019] Depend on Figure 1and Figure 2 It can be seen that electrons travel from the n-type electrode through the n-In... x Ga 1-x As 1-y P y Restriction layer 2 and n-In x Ga 1-x As 1-y P y Waveguide layer 3 is injected into the active region, and holes travel from the p-type electrode through p-Al x Ga 1-x As confinement layer 8 and p-Al x Ga 1-x As waveguide layer 7 is injected into the active region, where it recombines to generate photons.

[0020] This invention selects a suitable InGaAsP material composition as the n-type waveguide layer and confinement layer, modulates the band structure, reduces the band step difference, and reduces carrier loss. This solves the problems of severe carrier optical absorption loss and large energy loss during transport in epitaxial structures, reduces optical loss and leakage current during operation, thereby reducing the series resistance and operating voltage of the laser, and improving the output power and electro-optical conversion efficiency of the laser.

[0021] This invention also discloses a method for fabricating an asymmetric heteroguide 808nm semiconductor laser structure, which, based on the aforementioned asymmetric heteroguide 808nm semiconductor laser structure, specifically includes the following steps: Step 1. Cleaning the surface of the n-GaAs substrate 1 with an off-angle: Introduce hydrogen gas and maintain the reaction chamber temperature at 700–740 °C for 5–15 minutes to remove particulate contaminants and oxygen atoms from the surface of the n-GaAs substrate 1. The off-angle of the n-GaAs substrate 1 is 0–1°.

[0022] Step 2. n-In x Ga 1-x As 1-y Py confinement layer 2 growth: The reaction chamber temperature was reduced to 650~680 ℃, the trimethylgallium flow rate was 45 sccm, the arsine flow rate was 800~1500 sccm, the phosphine flow rate was 300~500 sccm, and the trimethylindium flow rate was 240 sccm, and n-In was grown on n-GaAs substrate 1. x Ga 1-x As 1-y Py confinement layer 2; n-type doping concentration is 1×10⁻⁶ 19 cm -3 ;Use n-In x Ga 1-x As 1-y Py confinement layer 2 provides electrons and confines the distribution of the light field.

[0023] Step 3. n-In x Ga 1-x As 1-y P y Waveguide layer 3 growth: The reaction chamber temperature was kept constant, the flow rate of trimethylgallium was 45 sccm, the flow rate of arsine was 800–1500 sccm, the flow rate of phosphine was 300–500 sccm, and the flow rate of trimethylindium was 240 sccm, in n-In x Ga 1-x As 1-y n-In grown on Py confinement layer 2 x Ga 1-x As 1-y P y Waveguide layer 3; n-type doping concentration is 1×10 17 ~1×10 18 cm -3 ; via n-In x Ga 1-x As 1-y P y Waveguide layer 3 provides a site for photon reflection and propagation, and further restricts carrier leakage.

[0024] Step 4. n-In x Ga 1-x As 1-y P y Barrier layer 4 growth: The reaction chamber temperature was kept constant, the flow rate of trimethylgallium was 45 sccm, the flow rate of arsine was 800–1500 sccm, the flow rate of phosphine was 300–500 sccm, and the flow rate of trimethylindium was 240 sccm, in n-In x Ga 1-x As 1-y P y n-In grown on waveguide layer 3 x Ga 1-x As 1-y P y Barrier layer 4, n-In x Ga 1-x As 1-y P y Barrier layer 4 can confine holes in quantum wells.

[0025] Step 5. In x Ga 1-x As 1-y P y Quantum well layer 5 growth: The reaction chamber temperature was reduced to 550–650 °C, the trimethylgallium flow rate was 90 sccm, and the arsine flow rate was 440 sccm, in n-In x Ga1-x As 1-y P y In grown on barrier layer 4 x Ga 1-x As 1-y P y Quantum well layer 5; in In x Ga 1-x As 1-y P y In quantum well layer 5, electrons and holes can recombine effectively to produce photons.

[0026] Step 6. p-GaAs 1-x P x Barrier layer 6 growth: The reaction chamber temperature was raised to 650–680 °C, the trimethylgallium flow rate was 45 sccm, the arsine flow rate was 800–1500 sccm, the phosphine flow rate was 300–500 sccm, and In… x Ga 1-x As 1-y P y p-GaAs grown on quantum well layer 5 1-x P x Barrier layer 6; utilizing p-GaAs 1-x P x The sixth barrier layer confines electrons within the quantum well.

[0027] Step 7. p-Al x Ga 1-x As waveguide layer 7 growth: The reaction chamber temperature remained constant, the flux density was 97 sccm for trimethylgallium, 28 sccm for trimethylaluminum, 1160 sccm for arsine, and 5-20 sccm for carbon tetrabromide, in p-GaAs... 1-x P x p-Al grown on barrier layer 6 x Ga 1-x As waveguide layer 7, p-type doping concentration is 1×10⁻⁶ 17 ~1×10 18 cm -3 ; via p-Al x Ga 1-x As waveguide layer 7 provides a place for photon reflection and propagation, and further restricts carrier leakage.

[0028] Step 8. p-Al x Ga 1-x As confinement layer 8 growth: The reaction chamber temperature was kept constant, the flow rate of trimethylgallium was 75 sccm, the flow rate of trimethylaluminum was 70 sccm, the flow rate of arsine was 1160 sccm, and the flow rate of carbon tetrabromide was 5~20 sccm, in p-Al x Ga1-x p-Al grown on As waveguide layer 7 x Ga 1-x As confinement layer 8, p-type doping concentration 1×10⁸ 19 cm -3 p-Al x Ga 1-x As confinement layer 8 provides holes, confines the optical field distribution and carrier leakage, and restricts photons and carriers from leaking into the epitaxial structure outside the confinement layer, thereby reducing carrier and photon losses.

[0029] Step 9. Growth of p-GaAs contact layer 9: The reaction chamber temperature remains constant, the flow rate of trimethylgallium is 90 sccm, the flow rate of arsine is 440 sccm, and the flow rate of carbon tetrabromide is 10~25 sccm. x Ga 1-x A p-GaAs contact layer 9 is grown on the As confinement layer 8, and an ohmic contact is formed between the p-GaAs contact layer 9 and the P motor.

[0030] The asymmetric waveguide epitaxial structure of this invention utilizes the difference in waveguide thickness on both the n and p sides to shift the peak center of the optical field distribution towards the n side, thereby reducing optical loss. However, conventional n- and p-side waveguide layers typically use homogeneous semiconductors, resulting in a relatively fixed band structure between the waveguide layer and the confinement layer. This can cause losses during carrier transport, thus affecting the operating voltage and output power. In contrast, the heterogeneous waveguide structure selects an InGaAsP material system with a small conduction band difference on the n side and an AlGaAs material system with a large conduction band difference on the p side. By optimizing the band structure, it reduces the voltage drop of the device and increases the confinement of the injected carriers, thereby improving the electrical characteristics of the device.

[0031] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An asymmetric heterostructure waveguide 808nm semiconductor laser structure, characterized in that: Includes an n-GaAs substrate (1) and n-In epitaxial growth directions arranged sequentially. x Ga 1-x As 1-y Py confinement layer (2), n-In x Ga 1-x As 1-y P y Waveguide layer (3), n-In x Ga 1-x As 1-y P y Barrier layer (4), In x Ga 1-x As 1-y P y Quantum well layer (5), p-GaAs 1-x P x Barrier layer (6), p-Al x Ga 1-x As waveguide layer (7), p-Al x Ga 1-x As confinement layer (8), p-GaAs contact layer (9), wherein: The n-GaAs substrate (1) is grown on a crystal plane, and n-In x Ga 1-x As 1-y P y The confinement layer (2) is grown on the n-GaAs substrate (1); n-In x Ga 1-x As 1-y P y Waveguide layer (3) in n-In x Ga 1-x As 1-y P y Growth on confinement layer (2); n-In x Ga 1-x As 1-y P y Barrier layer (4) in n-In x Ga 1-x As 1-y P y Grown on waveguide layer (3), In x Ga 1-x As 1-y P y Quantum well layer (5) in n-Ga 1-x In x As 1-y P y Growth on barrier layer (4); p-GaAs 1-x P x Barrier layer (6) in In x Ga 1-x As 1-y P y Growth on quantum well layer (5); p-Al x Ga 1- x As waveguide layer (7) in p-GaAs 1-x P x Growth on barrier layer (6); p-Al x Ga 1-x As confinement layer (8) in p-Al x Ga 1-x As waveguide layer (7) is grown on p-GaAs; p-GaAs contact layer (9) is grown on p-Al x Ga 1-x As confinement layer (8) grows; The n-In x Ga 1-x As 1-y P y The confinement layer (2) has a thickness of 1000~1500nm and a doping concentration the same as that of the n-GaAs substrate (1). x Ga 1-x As 1-y P y In the confinement layer (2), the In component x satisfies 0.4 < x < 0.55, and the P component satisfies 0.8 < y < 0.

95. With In and P components fixed, n-In... x Ga 1-x As 1-y P y The In and P components in the confinement layer (2) are respectively related to n-In x Ga 1-x As 1-y P y The maximum values ​​of In and P components in waveguide layer (3) are the same; p-Al x Ga 1-x The As confinement layer (8) has a thickness of 1000~1500 nm and a doping concentration that is the same as that of the p-GaAs contact layer (9). x Ga 1-x In the As confinement layer (8), the AL component satisfies 0.4 < x < 0.6, the AL component is fixed, and it is related to p-Al x Ga 1-x The maximum values ​​of the Al component are the same in the As waveguide layer (7); The n-In x Ga 1-x As 1-y P y Confinement layer (2) and p-Al x Ga 1-x The doping concentration of the As confinement layer (8) is fixed.

2. The asymmetric heterostructure waveguide 808nm semiconductor laser structure according to claim 1, characterized in that: The n-GaAs substrate (1) has a thickness of 1000~3000 nm and a doping concentration of 5×10⁻⁶. 18 ~1×10 19 cm -3 ; The thickness of the p-GaAs contact layer (9) is 100~500nm, and the constant doping concentration of the p-GaAs contact layer (9) is 5×10⁻⁶. 19 ~1×10 20 cm -3 .

3. The asymmetric heterostructure waveguide 808nm semiconductor laser structure according to claim 1, characterized in that: The In x Ga 1-x As 1-y P y The quantum well layer (5) has a thickness of 3~10 nm, with the In composition satisfying 0 < x < 0.10 and the P composition satisfying 0 < y < 0.

15. x Ga 1-x As 1-y P y The quantum well layer (5) is undoped.

4. The asymmetric heterostructure waveguide 808nm semiconductor laser structure according to claim 1, characterized in that: The n-Ga 1-x In x As 1-y P y The barrier layer (4) has a thickness of 10~20nm, the In composition satisfies 0.4<x<0.55, and the P composition satisfies 0.8<y<0.95; p-GaAs 1-x P x The thickness of the barrier layer (6) and n-Ga 1-x In x As 1-y P y The barrier layer (4) has the same thickness, and the P component satisfies 0.2 < x < 0.7; The n-Ga 1-x In x As 1-y P y Barrier layer (4) and p-GaAs 1-x P x The barrier layer (6) is undoped.

5. The asymmetric heteroguide 808nm semiconductor laser structure according to claim 1, characterized in that: The n-In x Ga 1-x As 1-y P y The waveguide layer (3) has a thickness of 300~700nm, and the In and P components are gradually varied. The maximum value of the In component is related to n-In. x Ga 1-x As 1-y P y The In components in the confinement layer (2) are the same, and the minimum value of the In component is greater than 0; n-In x Ga 1-x As 1-y P y The waveguide layer (3) has a gradually changing doping concentration, with the maximum doping concentration being less than n-In. x Ga 1-x As 1-y P y The doping concentration of the confinement layer (2); p-Al x Ga 1-x The thickness of the As waveguide layer (7) is 300~700nm, and the Al composition gradually changes. The maximum value of the Al composition is related to p-Al. x Ga 1- x The Al components in the As confinement layer (8) are the same, and the minimum Al component value is greater than 0; p-Al x Ga 1-x The As waveguide layer (7) has a gradually changing doping concentration, with the maximum doping concentration being less than that of p-Al. x Ga 1-x The doping concentration of the As confinement layer (8).

6. A method for fabricating an asymmetric heteroguide 808nm semiconductor laser structure, based on the asymmetric heteroguide 808nm semiconductor laser structure according to any one of claims 1 to 5, characterized in that, Specifically, the following steps are included: Step 1. Clean the surface of the n-GaAs substrate (1) with an off-angle: Introduce hydrogen gas and keep the reaction chamber temperature at 700-740 °C for 5-15 minutes to clean off particulate contaminants on the surface of the n-GaAs substrate (1) and remove oxygen atoms from the surface of the n-GaAs substrate (1). Step 2. n-In x Ga 1-x As 1-y Py confinement layer (2) growth: The reaction chamber temperature was reduced to 650~680 ℃, the flow rate of trimethylgallium was 45 sccm, the flow rate of arsine was 800~1500 sccm, the flow rate of phosphine was 300~500 sccm, and the flow rate of trimethylindium was 240 sccm. n-In was grown on the n-GaAs substrate (1). x Ga 1-x As 1-y Py confinement layer (2); n-type doping concentration is 1×10⁻⁶ 19 cm -3 ; Step 3. n-In x Ga 1-x As 1-y P y Waveguide layer (3) growth: The temperature in the reaction chamber remained constant, the flow rate of trimethylgallium was 45 sccm, the flow rate of arsine was 800-1500 sccm, the flow rate of phosphine was 300-500 sccm, and the flow rate of trimethylindium was 240 sccm, in n-In x Ga 1-x As 1-y n-In grown on Py confinement layer (2) x Ga 1-x As 1-y P y Waveguide layer (3); n-type doping concentration is 1×10 17 ~1×10 18 cm -3 ; Step 4. n-In x Ga 1-x As 1-y P y Barrier layer (4) growth: The reaction chamber temperature remained constant, the flow rate of trimethylgallium was 45 sccm, the flow rate of arsine was 800–1500 sccm, the flow rate of phosphine was 300–500 sccm, and the flow rate of trimethylindium was 240 sccm. x Ga 1-x As 1-y P y n-In grown on waveguide layer (3) x Ga 1-x As 1-y P y Barrier layer (4); Step 5. In x Ga 1-x As 1-y P y Quantum well layer (5) growth: The reaction chamber temperature was reduced to 550~650 ℃, the trimethylgallium flow rate was 90 sccm, the arsine flow rate was 440 sccm, and the n-In x Ga 1-x As 1-y P y In grows on barrier layer (4) x Ga 1-x As 1-y P y Quantum well layer (5); Step 6. p-GaAs 1-x P x Barrier layer (6) growth: The reaction chamber temperature is raised to 650-680 ℃, the trimethylgallium flow rate is 45 sccm, the arsine flow rate is 800-1500 sccm, the phosphine flow rate is 300-500 sccm, and the In x Ga 1-x As 1-y P y p-GaAs grown on quantum well layer (5) 1-x P x Barrier layer (6); Step 7. p-Al x Ga 1-x As waveguide layer (7) growth: The reaction chamber temperature remained constant, the flow rate of trimethylgallium was 97 sccm, the flow rate of trimethylaluminum was 28 sccm, the flow rate of arsine was 1160 sccm, and the flow rate of carbon tetrabromide was 5~20 sccm. 1-x P x p-Al grows on barrier layer (6) x Ga 1-x As waveguide layer (7), p-type doping concentration is 1×10 17 ~1×10 18 cm -3 ; Step 8. p-Al x Ga 1-x As confinement layer (8) growth: The reaction chamber temperature remained constant, the flow rate of trimethylgallium was 75 sccm, the flow rate of trimethylaluminum was 70 sccm, the flow rate of arsine was 1160 sccm, and the flow rate of carbon tetrabromide was 5~20 sccm. x Ga 1-x p-Al grown on As waveguide layer (7) x Ga 1-x As confinement layer (8), p-type doping concentration 1×10 19 cm -3 ; Step 9. p-GaAs contact layer (9) growth: The reaction chamber temperature remains constant, the trimethylgallium flow rate is 90 sccm, the arsine flow rate is 440 sccm, and the carbon tetrabromide flow rate is 10~25 sccm. x Ga 1-x A p-GaAs contact layer (9) is grown on the As confinement layer (8).

7. The method for fabricating the asymmetric heteroguide 808nm semiconductor laser structure according to claim 6, characterized in that, The n-GaAs substrate (1) has an offset angle of 0 to 1°.

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