阅读说明：本技术 一种GaAs基大功率激光器及其制备方法 (GaAs-based high-power laser and preparation method thereof ) 是由 李志虎 张新 夏伟 金光勇 于 2020-06-30 设计创作，主要内容包括：本发明涉及一种GaAs基大功率激光器及其制备方法,属于光电子技术领域,包括在GaAs衬底上由下至上依次生长的GaAs低温缓冲层、Al-(x)Ga-(y)As下限制层、AlGaAs下波导层、量子阱发光区、AlGaAs上波导层、Al-(X)Ga-(Y)As上限制层和GaAs帽层,其中,0≤x,y≤1,0≤X,Y≤1；所述量子阱发光区包括交替生长的AlGaAs阱层-AlGaAs垒层和GaAsP阱层-AlGaAs垒层。本发明采用无铝材料GaAsP作为量子阱有源区,可以保证长期工作的可靠性。(The invention relates to a GaAs-based high-power laser and a preparation method thereof, belonging to the technical field of photoelectrons x Ga y An As lower limiting layer, an AlGaAs lower waveguide layer, a quantum well light emitting region, an AlGaAs upper waveguide layer, and Al X Ga Y The GaAs cap layer is arranged on the As upper limiting layer, wherein X is more than or equal to 0, Y is less than or equal to 1, X is more than or equal to 0, and Y is less than or equal to 1; the quantum well light emitting region comprises AlGaAs well layer-AlGaAs barrier layers and GaAsP well layer-AlGaAs barrier layers which are alternately grown. The invention adopts the aluminum-free material GaAsP as the quantum well active region, and can ensure the reliability of long-term operation.)

1. A GaAs-based high-power laser is characterized by comprising a GaAs low-temperature buffer layer and Al which are sequentially grown on a GaAs substrate from bottom to top_xGa_yAn As lower limiting layer, an AlGaAs lower waveguide layer, a quantum well light emitting region, an AlGaAs upper waveguide layer, and Al_XGa_YThe GaAs cap layer is arranged on the As upper limiting layer, wherein X is more than or equal to 0, Y is less than or equal to 1, X is more than or equal to 0, and Y is less than or equal to 1;

the quantum well light emitting region comprises AlGaAs well layer-AlGaAs barrier layers and GaAsP well layer-AlGaAs barrier layers which are alternately grown.

2. The GaAs-based high power laser as claimed in claim 1, wherein one AlGaAs well layer and one AlGaAs barrier layer of the AlGaAs well layer-AlGaAs barrier layer constitute a pair of quantum wells, one GaAsP well layer and one AlGaAs barrier layer of the GaAsP well layer-AlGaAs barrier layer constitute a pair of quantum wells, and the number of pairs of quantum wells is 2-10;

preferably, the number of quantum well pairs is 2, i.e., 1 pair each of the AlGaAs well layer-AlGaAs barrier layer and the GaAsP well layer-AlGaAs barrier layer.

3. The GaAs-based high power laser as claimed in claim 2, wherein the thickness of the well layer in the quantum well light emitting region is 6-15 nm, and the thickness of the barrier layer is 10-100 nm.

4. A method for preparing a GaAs-based high power laser according to claim 3, comprising the steps of:

(1) placing the GaAs substrate in a growth chamber of MOCVD equipment in H₂Heating to 780 +/-30 ℃ in the environment, baking for 30-50 minutes, and introducing AsH₃Removing water and oxygen on the surface of the GaAs substrate to finish surface heat treatment;

(2) slowly reducing the temperature to 700 +/-20 ℃, and continuously introducing TMGa and AsH₃Growing a GaAs low-temperature buffer layer with the thickness of 50-1000nm on a GaAs substrate;

(3) keeping the temperature at 700 +/-20 ℃, and continuously introducing TMGa, TMAl and AsH₃Growing Al on the GaAs low-temperature buffer layer in the step (2)_xGa_yAn As lower limiting layer, wherein x is more than or equal to 0, and y is less than or equal to 1;

(4) the temperature is reduced to 650 +/-20 ℃ at Al_xGa_yGrowing an n-type AlGaAs lower waveguide layer on the As lower limiting layer;

(5) keeping the temperature at 650 +/-20 ℃, growing a quantum well light emitting region on the AlGaAs lower waveguide layer in the step (4), and introducing TMIn;

the quantum well light emitting region comprises AlGaAs well layer-AlGaAs barrier layers and GaAsP well layer-AlGaAs barrier layers which are alternately grown, one AlGaAs well layer and one AlGaAs barrier layer of the AlGaAs well layer-AlGaAs barrier layers form a pair of quantum wells, one GaAsP well layer and one AlGaAs barrier layer of the GaAsP well layer-AlGaAs barrier layers form a pair of quantum wells, the number of quantum well pairs is 2, namely the number of the AlGaAs well layer-AlGaAs barrier layers and the number of the GaAsP well layer-AlGaAs barrier layers are respectively 1 pair;

(6) keeping the temperature at 650 +/-20 ℃, and growing a p-type AlGaAs upper waveguide layer on the light emitting region of the quantum well;

(7) increasing the temperature to 700 +/-20 ℃, and continuously introducing TMGa, TMAl and AsH₃Growing Al on the AlGaAs upper waveguide layer_XGa_YUpper limit of AsPreparing a layer, wherein X is more than or equal to 0, and Y is less than or equal to 1;

(8) the temperature is reduced to 550 +/-20 ℃, and TMGa and AsH are continuously introduced₃In Al_XGa_YGrowing a GaAs cap layer on the As upper limiting layer;

(9) and after the epitaxial material grows, manufacturing a finished product LD device by using a conventional LD packaging technology.

5. The method for preparing GaAs-based high-power laser as claimed in claim 4, wherein the thickness of the GaAs low-temperature buffer layer is 100-300nm, and the doping concentration is 1E17-5E18 atoms/cm³；

Preferably, the GaAs low-temperature buffer layer has the thickness of 200nm and the doping concentration of 1E18 atoms/cm³；

Preferably, the doping concentration of AlGaAs in the step (3) is 1E17-5E18 atoms/cm³X is 0.3-0.5, y is 0.5-0.7;

preferably, the doping concentration of AlGaAs in the step (3) is 5E17 atoms/cm³X is 0.35, y is 0.65, Al_xGa_yThe thickness of the As lower limiting layer was 0.3. mu.m.

6. The method of claim 4, wherein the AlGaAs lower waveguide layer in the step (4) has a thickness of 0.5-3 μm and a doping concentration of 1E16-5E19 atoms/cm³；

Preferably, the AlGaAs lower waveguide layer comprises two layers, namely an early-grown waveguide layer and a later-grown SiAlGaAs layer or a TeAlGaAs layer, the AlGaAs lower waveguide layer has a thickness of 2 μm, the early-grown waveguide layer has a thickness of 1 μm, and the doping concentration is 1E17 atoms/cm³The later grown SiAlGaAs layer or teagaas layer is 1 μm thick and is an undoped layer.

7. The method for preparing a GaAs-based high-power laser device according to claim 4, wherein a thickness of a light emitting region of the quantum well In the step (5) is 0.1 to 0.3 μm, a logarithm of the quantum well is 2 to 10 pairs, and a molar ratio of In is 1 to 10%;

preferably, the thickness of the quantum well light emitting region is 0.1 μm, the number of quantum well pairs is 2, namely, one AlGaAs well layer-AlGaAs barrier layer and one GaAsP well layer-AlGaAs barrier layer, and the In molar ratio is 5% -7%.

8. The method of claim 4, wherein the AlGaAs upper waveguide layer in the step (6) has a thickness of 0.1 to 3 μm and a doping concentration of 1E18 to 5E18 atoms/cm³；

Preferably, the AlGaAs upper waveguide layer has a thickness of 1 μm and the doping concentration at 1/2 a away from the light emitting region of the quantum well is 1E17 atoms/cm³The 1/2 thickness near the light emitting region of the quantum well is undoped.

9. The method of claim 4, wherein the AlGaAs of step (7) is doped at a concentration of 1E17-5E18 atoms/cm³X is 0.3-0.5, Y is 0.5-0.7,

preferably, the doping concentration of AlGaAs of step (7) is 5E18 atoms/cm³X is 0.5, Y is 0.5, Al_XGa_YThe As upper limiting layer has a thickness of 1 μm.

10. The method for preparing GaAs-based high-power laser as claimed in claim 4, wherein the pressure of the MOCVD apparatus in the step (1) is 50-200 mbar;

the GaAs low-temperature buffer layer and the Al_xGa_yThe N-type doping sources of the As lower limiting layer and the AlGaAs lower waveguide layer are both Si₂H₆Or DETE; the AlGaAs upper waveguide layer and Al_XGa_YAn As upper limiting layer and a GaAs cap layer, and the doping sources are DEZn and CBr₄Or CP₂Mg; the doping source is introduced in a mode of firstly introducing AsH₃Then, continuously introducing the designed doping source flow, stopping introducing at intervals of 3-10 s, and continuously introducing in the rest time periods;

preferably, H₂The flow rate of the flow is 8000-50000 sccm; the purity of TMGa is 99.9999 percent, and the temperature of a constant temperature bath of the TMGa is (-5) to 15 ℃; the purity of the TMIn is 99.9999 percent, and the temperature of a constant temperature tank of the TMIn is 15 +/-5 ℃; of TMAlThe purity is 99.9999%, and the temperature of a thermostatic bath of TMAl is 10-28 ℃; AsH₃The purity of (2) is 99.9999%; si₂H₆The purity of (2) is 99.9999%; cp₂Mg purity of 99.9999%, Cp₂The temperature of the Mg thermostatic bath is 0-25 ℃, and CBr₄The temperature of the thermostatic bath is 0-10 ℃.

Technical Field

The invention relates to a GaAs-based high-power laser and a preparation method thereof, belonging to the technical field of photoelectrons.

Background

The high-power semiconductor laser has the advantages of small volume, light weight, high reliability, long service life and low cost, has more achievements, wide subject penetration and wide application range, and is widely applied to various fields of national economy such as laser processing, laser medical treatment, laser display and scientific research.

A GaAs-based high-power laser is one of semiconductor laser packaging structures, and the specific structure is that single Bar semiconductor lasers are uniformly distributed along the slow axis direction. The horizontal array packaging structure is commonly used as a pumping source of a solid laser, a plurality of semiconductor lasers with horizontal array structures are uniformly distributed around a crystal bar, the crystal bar is irradiated from different directions respectively, and high conversion efficiency can be realized. However, the reflected laser light may also directly irradiate the semiconductor laser chip, which may cause thermal damage to the chip, seriously affect the reliability and lifetime of the semiconductor laser, and put higher demands on the heat dissipation capability of the semiconductor laser chip.

Because the active region containing aluminum is easy to oxidize and generate dark line defects, the optical power density borne by the cavity surface is not high, so that the maximum power and the service life of the laser are reduced, and the influence on a high-power laser which needs to work for a long time is more serious. Compared with an aluminum-containing material, the aluminum-free material has higher thermal conductivity and electrical conductivity, so that the aluminum-free material has higher cavity surface optical catastrophe power density and is not easy to oxidize, thereby being beneficial to improving the power and the reliability of a device and being suitable for the field of high-performance application. Although the all-aluminum-free material structure has the advantages, the quantum well layer, the barrier and the upper limiting layer form a heterojunction, and the conduction band offset is small, so that strong carrier leakage is caused, the threshold current density is increased, the external quantum efficiency is reduced, the temperature characteristic is poor, and the application of the laser in certain environments and fields is limited.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the GaAs-based high-power laser and the preparation method thereof, and the non-aluminum material GaAsP is adopted as the quantum well active region, so that the reliability of long-term operation can be ensured.

The invention adopts the following technical scheme:

a GaAs-based high-power laser comprises a GaAs low-temperature buffer layer and an Al layer sequentially grown on a GaAs substrate from bottom to top_xGa_yAn As lower limiting layer, an AlGaAs lower waveguide layer, a quantum well light emitting region, an AlGaAs upper waveguide layer, and Al_XGa_YUpper As limiting layer and GaAn As cap layer, wherein X is more than or equal to 0, Y is more than or equal to 1, X is more than or equal to 0, and Y is more than or equal to 1;

the quantum well light emitting region comprises AlGaAs well layer-AlGaAs barrier layers and GaAsP well layer-AlGaAs barrier layers which are alternately grown.

Preferably, one AlGaAs well layer and one AlGaAs barrier layer of the AlGaAs well layer-AlGaAs barrier layer form a pair of quantum wells, one GaAsP well layer and one AlGaAs barrier layer of the GaAsP well layer-AlGaAs barrier layer form a pair of quantum wells, and the number of pairs of quantum wells is 2-10;

preferably, the number of quantum well pairs is 2, and the AlGaAs well layer-AlGaAs barrier layer and the GaAsP well layer-AlGaAs barrier layer are each 1, i.e., one AlGaAs well layer-AlGaAs barrier layer and one GaAsP well layer-AlGaAs barrier layer, as shown in fig. 1, may be expressed as (well AlGaAs barrier AlGaAs) + (well GaAsP barrier AlGaAs).

Preferably, the thickness of the well layer (including the total thickness of the AlGaAs well layer and the GaAsP well layer) of the quantum well light-emitting region is 6-15 nm, and the thickness of the barrier layer (the total thickness of the AlGaAs barrier layer) is 10-100 nm.

In the present invention, the GaAsP ratio is related to the wavelength to be achieved, and can be determined according to the forbidden bandwidth.

A preparation method of the GaAs-based high-power laser comprises the following steps:

(1) placing the GaAs substrate in a growth chamber of MOCVD equipment in H₂Heating to 780 +/-30 ℃ in the environment, baking for 30-50 minutes, and introducing AsH₃Removing water and oxygen on the surface of the GaAs substrate to finish surface heat treatment;

AsH₃the flow is preferably 1000ccm-10000 ccm;

(2) slowly reducing the temperature to 700 +/-20 ℃, and continuously introducing TMGa and AsH₃Growing a GaAs low-temperature buffer layer with the thickness of 50-1000nm on a GaAs substrate;

the slow drop can be set according to the process, in the step, the gradient of the slow drop of the temperature is less than or equal to 45 degrees, and TMGa and AsH are introduced₃The flow rate of (C) is determined according to the growth thickness, and the ratio V/III is preferably 20 or more;

(3) keeping the temperature at 700 +/-20 ℃, and continuously introducing TMGa, TMAl and AsH₃Growing Al on the GaAs low-temperature buffer layer in the step (2)_xGa_yLower limit of AsPreparing a layer, wherein x is more than or equal to 0, and y is less than or equal to 1;

introducing TMGa, TMAl and AsH₃When the V/III ratio is more than 20, preferably 90, according to the SIMS test, the V/III ratio of 90 can inhibit the self-doping of C in the material and improve the crystal quality of the growth of the material;

(4) the temperature is reduced to 650 +/-20 ℃ at Al_xGa_yGrowing an n-type AlGaAs lower waveguide layer on the As lower limiting layer;

(5) keeping the temperature at 650 +/-20 ℃, growing a quantum well light emitting region on the AlGaAs lower waveguide layer In the step (4), introducing TMIn, and verifying by experiments that the molar flow of In accounts for 3-10%, preferably 4-6%, and the pressure strain amount is optimal;

the quantum well light-emitting region comprises AlGaAs well layer-AlGaAs barrier layers and GaAsP well layer-AlGaAs barrier layers which are alternately grown, namely the AlGaAs well layer-AlGaAs barrier layers and the aAsP well layer-AlGaAs barrier layers are alternately grown, one AlGaAs well layer and one AlGaAs barrier layer of the AlGaAs well layer-AlGaAs barrier layers form a pair of quantum wells, one GaAsP well layer and one AlGaAs barrier layer of the GaAsP well layer-AlGaAs barrier layers form a pair of quantum wells, the number of quantum well pairs is 2, namely the AlGaAs well layer-AlGaAs barrier layers and the GaAsP well layer-AlGaAs barrier layers are respectively 1 pair, namely (well AlGaAs and) + (GaAsP AsP AlGaAs) structures;

(6) keeping the temperature at 650 +/-20 ℃, and growing a p-type AlGaAs upper waveguide layer on the light emitting region of the quantum well;

(7) increasing the temperature to 700 +/-20 ℃, and continuously introducing TMGa, TMAl and AsH₃Growing Al on the AlGaAs upper waveguide layer_XGa_YAn upper As limiting layer, wherein X is more than or equal to 0, and Y is less than or equal to 1;

introducing TMGa, TMAl and AsH₃When the V/III ratio is more than 20, preferably 90, according to the SIMS test, the V/III ratio of 90 can inhibit the self-doping of C in the material and improve the crystal quality of the growth of the material;

(8) the temperature is reduced to 550 +/-20 ℃, and TMGa and AsH are continuously introduced₃(the ratio V/III is preferably 20 or more), in the case of Al_XGa_YGrowing a GaAs cap layer on the As upper limiting layer;

(9) and after the epitaxial material grows, manufacturing a finished product LD device by using a conventional LD packaging technology.

Preferably, the thickness of the GaAs low-temperature buffer layer is 100-300nm, and the doping concentration is 1E17-5E18 atoms/cm³；

Preferably, the GaAs low-temperature buffer layer has the thickness of 200nm and the doping concentration of 1E18 atoms/cm³；

Preferably, the doping concentration of AlGaAs in the step (3) is 1E17-5E18 atoms/cm³X is 0.3-0.5, y is 0.5-0.7;

preferably, the doping concentration of AlGaAs in the step (3) is 5E17 atoms/cm³X is 0.35, y is 0.65, Al_xGa_yThe thickness of the As lower limiting layer was 0.3. mu.m.

Preferably, the thickness of the AlGaAs lower waveguide layer in the step (4) is 0.5-3 μm, and the doping concentration is 1E16-5E19 atoms/cm³；

Preferably, the AlGaAs lower waveguide layer comprises two layers, namely an early-grown waveguide layer and a later-grown SiAlGaAs layer or a TeAlGaAs layer, the AlGaAs lower waveguide layer has a thickness of 2 μm, the early-grown waveguide layer has a thickness of 1 μm, and the doping concentration is 1E17 atoms/cm³The later grown SiAlGaAs layer or teagaas layer is 1 μm thick and is an undoped layer.

Preferably, the thickness of the light emitting region of the quantum well In the step (5) is 0.1-0.3 μm, the logarithm of the quantum well is 2-10 pairs, and the molar ratio of In is 1% -10%;

preferably, the thickness of the quantum well light emitting region is 0.1 μm, the number of quantum well pairs is 2, namely, one AlGaAs well layer-AlGaAs barrier layer and one GaAsP well layer-AlGaAs barrier layer, and the In molar ratio is 5% -7%.

Preferably, the AlGaAs upper waveguide layer in the step (6) has a thickness of 0.1-3 μm and a doping concentration of 1E18-5E18 atoms/cm³；

Preferably, the AlGaAs upper waveguide layer has a thickness of 1 μm and the doping concentration at 1/2 a away from the light emitting region of the quantum well (i.e., 0.5 μm away from the light emitting region of the quantum well) is 1E17 atoms/cm³The 1/2 thickness near the light emitting region of the quantum well (i.e., 0.5 μm near the light emitting region of the quantum well) is undoped, which can increase the current spreading of the carrier concentration, and the operating voltage can be reduced by 5 under the same conditions％-15％。

Preferably, the AlGaAs doping concentration of the step (7) is 1E17-5E18 atoms/cm³X is 0.3-0.5, Y is 0.5-0.7,

preferably, the doping concentration of AlGaAs of step (7) is 5E18 atoms/cm³X is 0.5, Y is 0.5, Al_XGa_YThe As upper limiting layer has a thickness of 1 μm.

Preferably, the pressure of the MOCVD equipment in the step (1) is 50-200 mbar;

the GaAs low-temperature buffer layer and the Al_xGa_yThe N-type doping sources of the As lower limiting layer and the AlGaAs lower waveguide layer are both Si₂H₆Or DETE; the AlGaAs upper waveguide layer and Al_XGa_YAn As upper limiting layer and a GaAs cap layer, and the doping sources are DEZn and CBr₄Or CP₂Mg; the doping source is introduced in a mode of firstly introducing AsH₃Then, continuously introducing the designed doping source flow, stopping introducing at intervals of 3-10 s (preferably 5s), and continuously introducing for the rest time periods;

preferably, H₂The flow rate of the flow is 8000-50000 sccm; the purity of TMGa is 99.9999 percent, and the temperature of a constant temperature bath of the TMGa is (-5) to 15 ℃; the purity of the TMIn is 99.9999 percent, and the temperature of a constant temperature tank of the TMIn is 15 +/-5 ℃; the purity of TMAl is 99.9999%, and the temperature of a thermostatic bath of TMAl is 10-28 ℃; AsH₃The purity of (2) is 99.9999%; si₂H₆The purity of (2) is 99.9999%; cp₂Mg purity of 99.9999%, Cp₂The temperature of the Mg thermostatic bath is 0-25 ℃, and CBr₄The temperature of the thermostatic bath is 0-10 ℃.

The present invention is not described in detail, and the prior art can be adopted.

The invention has the beneficial effects that:

the invention adopts aluminum-free material GaAsP as a part of the quantum well active region, AlGaAs with low aluminum component as the upper waveguide layer and the lower waveguide layer, and Al with larger waveguide band order and containing high aluminum component material_xGa_yAs and Al_XGa_YAs is used As a lower limiting layer and an upper limiting layer, the active region structure is made of aluminum-free materials, and the reliability of long-term operation is guaranteed. Due to volumeThe larger conduction band steps between the light emitting region of the sub-well and the waveguide layer and between the light emitting region of the quantum well and the upper limiting layer can prevent the overflow of carriers, reduce the threshold current density and enable the laser to work at high temperature.

The GaAsP/AlGaAs quantum well is tensile strain in the junction plane, when the strain is large enough and the quantum effect of the well is not strong, the light hole of the valence band moves above the heavy hole, the output laser is TM polarized, and the TM mode LD can be used for crystals with special requirements on pump light.

In addition, relaxation of the GaAsP/AlGaAs tensile strained quantum well at the end faces forms a non-absorbing window, which can reduce absorption of photons by the end faces.

Drawings

FIG. 1 is a schematic structural diagram of a GaAs-based high-power laser device of the present invention;

wherein, the 1-GaAs low-temperature buffer layer is 2-Al_xGa_yA lower As limiting layer, a lower 3-AlGaAs waveguide layer, a 4-quantum well light emitting region, an upper 5-AlGaAs waveguide layer, and 6-Al_XGa_YAn As upper limiting layer and a 7-GaAs cap layer.

The specific implementation mode is as follows:

in order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific examples, but not limited thereto, and the present invention is not described in detail and is in accordance with the conventional techniques in the art.

Example 1:

a GaAs-based high-power laser comprises a GaAs low-temperature buffer layer 1 and an Al layer sequentially grown on a GaAs substrate from bottom to top_xGa_yAn As lower limiting layer 2, an AlGaAs lower waveguide layer 3, a quantum well light emitting region 4, an AlGaAs upper waveguide layer 5, and Al_XGa_YAn As upper limiting layer 6 and a GaAs cap layer 7, wherein X is more than or equal to 0, Y is more than or equal to 1, X is more than or equal to 0, and Y is more than or equal to 1;

the quantum well light emitting region comprises AlGaAs well layer-AlGaAs barrier layers and GaAsP well layer-AlGaAs barrier layers which are alternately grown, one AlGaAs well layer and one AlGaAs barrier layer of the AlGaAs well layer-AlGaAs barrier layers form a pair of quantum wells, one GaAsP well layer and one AlGaAs barrier layer of the GaAsP well layer-AlGaAs barrier layers form a pair of quantum wells, the number of quantum well pairs is 2, and the AlGaAs well layer-AlGaAs barrier layers and the GaAsP well layer-AlGaAs barrier layers are 1 pair respectively, namely one AlGaAs well layer-AlGaAs barrier layer and one GaAsP well layer-AlGaAs barrier layer, which can be represented as (well AlGaAs barrier AlGaAs) + (well GaAsP barrier AlGaAs) as shown in FIG. 1;

the thickness of the well layer (including the total thickness of the AlGaAs well layer and the GaAsP well layer) of the quantum well light-emitting region is 6-15 nm, and the thickness of the barrier layer (the total thickness of the AlGaAs barrier layer) is 10-100 nm.

Example 2:

a preparation method of a GaAs-based high-power laser comprises the following steps:

(1) placing the GaAs substrate in a growth chamber of MOCVD equipment in H₂Heating to 780 +/-30 ℃ in the environment, baking for 30-50 minutes, and introducing AsH₃Removing water and oxygen on the surface of the GaAs substrate to finish surface heat treatment;

AsH₃the flow is 1000ccm-10000 ccm;

(2) slowly reducing the temperature to 700 +/-20 ℃, and continuously introducing TMGa and AsH₃Growing a GaAs low-temperature buffer layer 1 with the thickness of 50-1000nm on a GaAs substrate;

(3) keeping the temperature at 700 +/-20 ℃, and continuously introducing TMGa, TMAl and AsH₃Growing Al on the GaAs low-temperature buffer layer 1 of the step (2)_xGa_yAn As lower limiting layer 2, wherein x is more than or equal to 0 and y is less than or equal to 1;

(4) the temperature is reduced to 650 +/-20 ℃ at Al_xGa_yAn n-type AlGaAs lower waveguide layer 3 grows on the As lower limiting layer 2;

(5) keeping the temperature at 650 +/-20 ℃, growing a quantum well light emitting region 4 on the AlGaAs lower waveguide layer 3 In the step (4), and introducing TMIn, wherein the molar flow of In accounts for 4-6%;

the quantum well light emitting region comprises AlGaAs well layer-AlGaAs barrier layers and GaAsP well layer-AlGaAs barrier layers which are alternately grown, namely the AlGaAs well layer-AlGaAs barrier layers and the aAsP well layer-AlGaAs barrier layers are alternately grown, one AlGaAs well layer and one AlGaAs barrier layer of the AlGaAs well layer-AlGaAs barrier layers form a pair of quantum wells, one GaAsP well layer and one AlGaAs barrier layer of the GaAsP well layer-AlGaAs barrier layers form a pair of quantum wells, the number of quantum well pairs is 2, namely the AlGaAs well layer-AlGaAs barrier layers and the GaAsP well layer-AlGaAs barrier layers are respectively 1 pair, namely (well AlGaAs and) + (GaAsP AsP AlGaAs) structures, as shown in FIG. 1;

(6) keeping the temperature at 650 +/-20 ℃, and growing a p-type AlGaAs upper waveguide layer 5 on the light emitting region of the quantum well;

(7) increasing the temperature to 700 +/-20 ℃, and continuously introducing TMGa, TMAl and AsH₃Growing Al on the AlGaAs upper waveguide layer_XGa_YAn upper As limiting layer, wherein X is more than or equal to 0, and Y is less than or equal to 1;

(8) the temperature is reduced to 550 +/-20 ℃, and TMGa and AsH are continuously introduced₃In Al_XGa_YGrowing a GaAs cap layer on the As upper limiting layer;

(9) and after the epitaxial material grows, manufacturing a finished product LD device by using a conventional LD packaging technology.

Example 3:

a preparation method of a GaAs-based high-power laser is disclosed in example 2, except that the GaAs low-temperature buffer layer 1 has a thickness of 200nm and a doping concentration of 1E18 atoms/cm³；

The doping concentration of AlGaAs in the step (3) is 5E17 atoms/cm³X is 0.35, y is 0.65, Al_xGa_yThe thickness of the As lower limiting layer 2 is 0.3 μm;

the AlGaAs lower waveguide layer 3 comprises two layers, namely a waveguide layer grown firstly and a SiAlGaAs layer or a TeAlGaAs layer grown later, the thickness of the AlGaAs lower waveguide layer is 2 mu m, the thickness of the waveguide layer grown firstly is 1 mu m, and the doping concentration is 1E17 atoms/cm³The later grown SiAlGaAs layer or teagaas layer is 1 μm thick and is an undoped layer.

The thickness of the quantum well light emitting region 4 is 0.1 μm, the number of quantum well pairs is 2, namely, one AlGaAs well layer-AlGaAs barrier layer and one GaAsP well layer-AlGaAs barrier layer, and the In molar ratio is 5-7%.

The AlGaAs upper waveguide layer 5 has a thickness of 1 μm and a doping concentration of 1E17 atoms/cm at 1/2 thicknesses away from the light emitting region of the quantum well (i.e., 0.5 μm away from the light emitting region of the quantum well)³The 1/2 thickness near the quantum-well light emitting region (i.e., 0.5 μm near the quantum-well light emitting region) is undoped.

The doping concentration of AlGaAs of the step (7) is 5E18 atoms/cm³X is 0.5, Y is 0.5, Al_XGa_YThe As upper limiting layer 6 has a thickness of 1 μm.

Example 4:

a preparation method of a GaAs-based high-power laser, as shown in example 2, except that the pressure of the MOCVD equipment in the step (1) is 50-200 mbar;

GaAs Low temperature buffer layer 1, Al_xGa_yThe N-type doping sources of the As lower limiting layer 2 and the AlGaAs lower waveguide layer 3 are both Si₂H₆Or DETE; AlGaAs upper waveguide layer 5, Al_XGa_YAn As upper limiting layer 6 and a GaAs cap layer 7, and the doping sources are DEZn and CBr₄Or CP₂Mg; the doping source is introduced in a mode of firstly introducing AsH₃Then, continuously introducing the designed doping source flow, stopping introducing at an interval of 5s, and continuously introducing in the rest time periods;

H₂the flow rate of the flow is 8000-50000 sccm; the purity of TMGa is 99.9999 percent, and the temperature of a constant temperature bath of the TMGa is (-5) to 15 ℃; the purity of the TMIn is 99.9999 percent, and the temperature of a constant temperature tank of the TMIn is 15 +/-5 ℃; the purity of TMAl is 99.9999%, and the temperature of a thermostatic bath of TMAl is 10-28 ℃; AsH₃The purity of (2) is 99.9999%; si₂H₆The purity of (2) is 99.9999%; cp₂Mg purity of 99.9999%, Cp₂The temperature of the Mg thermostatic bath is 0-25 ℃, and CBr₄The temperature of the thermostatic bath is 0-10 ℃.

It is noted that GaAs and GaAsP materials of the present invention are lattice mismatched heteroepitaxial materials, and only when the epitaxial layer is thin enough, the energy of elastic strain is kept lower than the energy of dislocation formation. Therefore, when designing GaAsP quantum well material, the critical thickness h determined by the mismatch stress caused by different lattice constants needs to be considered first_cThe thickness of the epitaxial layer is required to be less than the critical thickness h_c。

Critical thickness h_cCan be estimated by a mechanical equilibrium model of Matthews and is used for describing the relation between the critical thickness and the mismatch degree f in the elastic strain range, as shown in a formula (1-1), wherein a is the lattice constant of the strain layer, the mismatch degree f is delta a/a,ν is Poisson's ratio ν is C11/(C11+ C12), C11 and C12 are elastic coefficients of the material, and the dependence of the critical thickness and the lattice mismatch can be theoretically calculated according to the formula;

however, in the actual production process, due to the influence of other factors in the epitaxial growth, such as the fluctuation of the quantum well thickness, the actual critical thickness is much smaller than the theoretical calculation value h_cIn an actual process experiment, a theoretical calculation result can provide a basic basis for structure design and provide a directional reference for designing growth thickness.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.