An AlGaInP red light semiconductor laser device with a strained superlattice structure and its preparation method

Abstract

The present invention relates to an AlGaInP red light semiconductor laser device with a strained superlattice structure and a preparation method thereof, which comprises, from bottom to top, a substrate, a buffer layer, a lower transition layer, a lower confinement layer, a lower waveguide layer, (Al a1 Ga 1‑a1 ) b1 In 1‑b1 P / (Al a1 Ga 1‑a1 ) b2 In 1‑b2 P strained superlattice, first quantum well, barrier layer, second quantum well, upper waveguide layer, first upper confinement layer, corrosion stop layer, second upper confinement layer, upper transition layer and GaAs cap layer; after the AlGaInP graded waveguide layer of the present invention is grown, the strained superlattice structure is inserted to improve the material growth quality, inhibit interface non-radiative recombination, thereby reducing the threshold current and improving the aging characteristics.

Description

Technical Field

[0001] The invention relates to an AlGaInP red light semiconductor laser device with a strained superlattice structure and a preparation method thereof, belonging to the technical field of optoelectronics. Background Art

[0002] AlGaInP red semiconductor lasers are characterized by their small size, light weight, low power consumption, direct modulation, high efficiency, and reliability. They hold broad application prospects in plastic optical fiber transmission for short-range all-optical networks, medical aesthetics, laser displays, and industrial measurement. However, the maximum conduction band energy gap in the AlGaInP laser material structure is only 270 meV, resulting in poor electron confinement. This leads to severe electron overflow from the active region into the P-type confinement layer, particularly as operating temperature increases. This electron overflow worsens, leading to an increase in threshold current, a decrease in slope efficiency, and ultimately an increase in operating current, which generates more waste heat. Thermal saturation, however, limits further increases in output power.

[0003] The IEEE Journal of Selected Topics in Quantum Electronics, Vol. 17(6), 2011, Pg 1723–1726, points out that reducing the threshold current density helps suppress carrier overflow. Using AlInP as the confinement layer maximizes the optical confinement factor, thereby reducing the threshold current density. Red semiconductor lasers typically use strained GaInP quantum wells or low-Al content AlGaInP quantum wells to achieve lasing wavelengths of 615-710 nm. The optimal growth conditions for the confinement layer and quantum well are different.

[0004] The Journal of Crystal Growth, Vol. 310, 2008, pp. 5175–5177, notes that the optimal processes for improving GaInP and AlGaInP growth quality differ. To improve material growth quality and achieve optimal performance, different growth conditions are required. However, process variations during growth, particularly temperature fluctuations, can easily induce stress or defects, as the matching flux and temperature at different temperatures is not strictly linear. This can lead to poor material growth quality, increased non-radiative recombination, and reduced threshold current density.

[0005] The literature Applied Physics Letters, Vol 58(17), 1991, Pg 1822–1824, points out that inserting a superlattice structure on both sides of the active region can effectively suppress non-radiative recombination at the interface and improve the quality of material growth. However, the original paper used AlInP / GaInP superlattice, which has Al component diffusion, such as growth at the quantum well interface, affecting the laser emission wavelength.

[0006] The IEEE photonics technology letters, Vol 3(5), 1991, Pg 397–399, states that the waveguide layer gradient and the addition of a low-Al composition stabilization layer to the waveguide layer at the quantum well can help lower the threshold and improve electrical parameters. However, the original paper stated that the waveguide stabilization layer had a stable composition and did not use a superlattice structure to improve material growth quality. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides an AlGaInP red light semiconductor laser device with a strained superlattice structure;

[0008] The present invention also provides a method for preparing the AlGaInP red light semiconductor laser.

[0009] Explanation of terms

[0010] MOCVD is a new vapor phase epitaxial growth technology developed on the basis of vapor phase epitaxy (VPE).

[0011] The technical solutions of the present invention are as follows:

[0012] In a first aspect, the present invention provides an AlGaInP red light semiconductor laser device with a strained superlattice structure.

[0013] An AlGaInP red light semiconductor laser device with a strained superlattice structure, comprising, from bottom to top, a GaAs substrate, a GaAs buffer layer, a GaAs 0.5 In 0.5 P lower transition layer, Al 0.5 In 0.5 P lower confinement layer, (Al 1-x1 Ga x1 ) y1 In 1-y1 P lower waveguide layer, (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice, Ga 1-x2 In x2 P first quantum well, (Al 1- x3 Ga x3 ) y2 In 1-y2 P barrier layer, Ga 1-x4 In x4 P second quantum well, (Al1-x5 Ga x5 ) y3 In 1-y3 P upper waveguide layer, Al 0.5 In 0.5 P first upper confinement layer, Ga 1-x6 In x6 P corrosion stop layer, Al 0.5 In 0.5 P second upper confinement layer, Ga 0.5 In 0.5 P upper transition layer and GaAs cap layer;

[0014] Among them, 0.05≤x1≤0.6, 0.4≤y1≤0.6; 0.5≤x2≤0.7; 0.3≤x3≤0.6, 0.4≤y2≤0.6; 0.5≤x4≤0.7; 0.05≤x5≤0.6, 0.4≤y3≤0.6; 0.4≤x6≤0.5; 0.25≤a1≤0.4, 0.4≤b1≤0.45; 0.55≤b2≤0.6.

[0015] The low Al content reduces the diffusion of Al between the AlGaInP and GaInP quantum wells, which affects the lasing wavelength. The Al content a1 in the superlattice remains unchanged, while b1 is greater than 0.5 and b2 is less than 0.5. The combined growth of tensile and compressive strain improves material growth quality and suppresses interfacial non-radiative recombination.

[0016] A second aspect of the present invention provides a method for preparing the AlGaInP red semiconductor laser device with a strained superlattice structure, the method comprising the following steps:

[0017] S1, placing the GaAs substrate in a growth chamber of an MOCVD device, heating the H2 environment to 720±10°C, and introducing AsH3 to perform surface heat treatment on the GaAs substrate;

[0018] S2, slowly lowering the temperature to 680±10°C at a cooling rate of no more than 30°C / min, continuing to introduce TMGa and AsH3 to grow the GaAs buffer layer on the GaAs substrate; the purpose is to prevent defects from propagating from the substrate into the confinement layer, provide a fresh growth interface, and improve the quality of material growth;

[0019] S3, maintaining the temperature at 680±10°C, pausing the growth on the GaAs buffer layer, introducing PH3, and achieving a growth pause by suspending the Group V source (99.9999% AsH3) and the Group III source (TMGa) for 3-30 seconds to deplete the As atoms in the growth chamber of the MOCVD equipment;

[0020] S4, the temperature is maintained at 680±10°C, TMGa, TMIn and PH3 are introduced, and the GaAs buffer layer is grown on the GaAs buffer layer. 0.5 In 0.5 P lower transition layer; its purpose is to reduce the band gap mutation and increase the electron migration rate;

[0021] S5, the temperature is slowly changed to 700±10℃, the heating rate is not higher than 60℃ / min, TMAl, TMIn, TMGa and PH3 are introduced, and the Ga 0.5 In 0.5 The n-type Al is grown on the P lower transition layer. 0.5 In 0.5 P lower limiting layer;

[0022] S6, the temperature is slowly changed to 650±10℃, the cooling rate is not higher than 60℃ / min, TMAl, TMIn, TMGa and PH3 are introduced, and the n-type Al 0.5 In 0.5 The (Al 1-x1 Ga x1 ) y1 In 1-y1 P lower waveguide layer;

[0023] S7, the temperature is maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and the 1-x1 Ga x1 ) y1 In 1- y1 The (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strain superlattice, by changing the flow of TMAl and TMGa, the flow of TMIn remains unchanged, the ratio of Al and Ga remains unchanged, and the low Al component is maintained, while the In ratio is adjusted to achieve component changes, thereby achieving tensile strain and compressive strain (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice growth;

[0024] S8, the temperature is maintained at 650±10℃, TMIn, TMGa and PH3 are continuously introduced, and the (Al a1 Ga 1-a1 ) b1 In 1- b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 The GaN-P strained superlattice is grown on the 1-x2 In x2 P first quantum well;

[0025] S9, the temperature is maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and the Ga 1-x2 In x2 The (Al 1-x3 Ga x3 ) y2 In 1-y2 P barrier layer;

[0026] S10, the temperature is maintained at 650±10℃, TMIn, TMGa and PH3 are continuously introduced, and in the (Al 1-x3 Ga x3 ) y2 In 1- y2 The Ga 1-x4 In x4 P second quantum well;

[0027] S11, the temperature is slowly changed to 700±10℃, the heating rate is not higher than 60℃ / min, and TMAl, TMIn, TMGa and PH3 are continuously introduced. 1-x4 In x4 The (Al 1-x5 Ga x5 ) y3 In 1-y3 The waveguide layer on P; a too high heating rate will cause great damage to the equipment, and at the same time affect the stress release caused by slight mismatch during the growth process, so the heating and cooling rates are generally not too fast.

[0028] S12, the temperature is maintained at 700±10℃, TMAl, TMIn and PH3 are continuously introduced, and the (Al 1-x5 Ga x5 ) y3 In 1- y3 The P-type Al 0.5 In 0.5P first upper confinement layer;

[0029] S13, the temperature is maintained at 700±10℃, TMGa, TMIn and PH3 are continuously introduced, and the P-type Al 0.5 In 0.5 The P-type Ga 1-x6 In x6 P corrosion stop layer;

[0030] S14, the temperature is maintained at 700±10℃, TMAl, TMIn and PH3 are continuously introduced, and the P-type Ga 1-x6 In x6 The P-type Al 0.5 In 0.5 P second upper confinement layer;

[0031] S15, the temperature is gradually changed to 680±10℃, the cooling rate is not higher than 60℃ / min, TMIn, TMGa and AsH3 are introduced, and the P-type Al 0.5 In 0.5 The second upper confinement layer of P is grown on the Ga 0.5 In 0.5 P upper transition layer;

[0032] S16, lower the temperature to 540±10℃, with the cooling rate not exceeding 40℃ / min, continue to introduce TMGa and AsH3, and 0.5 In 0.5 A GaAs cap layer is grown on the P upper transition layer.

[0033] Further preferably, in step S6, the cooling rate is 40°C / min. If the cooling rate is too fast, it may easily cause In incorporation differences and form mismatch.

[0034] Further preferably, in step S7, in the (Al 1-x1 Ga x1 ) y1 In 1-y1 The (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice, the specific implementation process is:

[0035] First, the TMIn flow rate is fixed, and the flow rate is greater than the matching flow rate during the growth of Al#1 and Ga#1 to form tensile strain;

[0036] Then, turn off Al#1 and Ga#1, switch to Al#2 and Ga#2 growth, the flow rate is less than the matching flow rate, forming a compressive strain material; alternating growth, thus forming tensile strain and compressive strain (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice.

[0037] According to the preferred embodiment of the present invention, in step S7, the (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strain superlattice, where 0.25≤a1≤0.4, 0.4≤b1≤0.45, compressive strain thickness is 13-23 angstroms; 0.55≤b2≤0.6, tensile strain thickness is 17-26 angstroms, with a total of 3-7 pairs.

[0038] More preferably, a1=0.35, b1=0.4, the compressive strain thickness is 17 angstroms, b2=0.6, the tensile strain thickness is 23 angstroms, and there are 5 pairs in total.

[0039] Among them, a1 uses a low Al component to reduce the impact of Al component diffusion between AlGaInP and GaInP quantum wells on the lasing wavelength; by adjusting the In component ratio, a combined superlattice of compressive strain and tensile strain is realized, the material growth quality is optimized, the impact of process switching on the subsequent quantum well growth is avoided, the interface scattering effect is reduced, and the threshold current density is reduced.

[0040] According to the preferred embodiment of the present invention, in step S2, the doping source of the GaAs buffer layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm 3 , thickness of 0.1-0.3μm;

[0041] Further preferably, the thickness of the GaAs buffer layer is 0.2 μm, and the doping concentration is 2E18 atoms / cm 3 .

[0042] According to the preferred embodiment of the present invention, in step S4, the Ga 0.5 In 0.5 The doping source of the P lower transition layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm 3 , thickness of 0.1-0.3μm;

[0043] Further preferably, the Ga 0.5 In 0.5 The thickness of the P lower transition layer is 0.2 μm, and the doping concentration is 4E18 atoms / cm 3 .

[0044] According to the present invention, preferably, in step S5, the Al 0.5 In 0.5 The doping source of the P lower confinement layer is Si2H6, and the doping concentration is 7E17-2E18 atoms / cm 3 , thickness of 0.7-1.5μm;

[0045] Further preferably, the Al 0.5 In 0.5 The thickness of the P lower confinement layer is 1.2 μm, and the doping concentration is 1E18 atoms / cm 3 .

[0046] According to the present invention, preferably, in step S6, the (Al 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the waveguide layer under P is 0.05-0.15 μm, not intentionally doped, 0.05≤x1≤0.6, 0.4≤y1≤0.6;

[0047] More preferably, x1 is gradually changed from 0.05 to 0.5, the composition gradient growth time is 60s, y1=0.5, and the thickness is 0.1 μm. The temperature is lowered and V / III is adjusted in the waveguide layer to achieve the optimal growth process switching between AlInP and GaInP.

[0048] According to the preferred embodiment of the present invention, in step S8, the Ga 1-x2 In x2 The thickness of the P first quantum well is 4-7nm, it is not intentionally doped, and it is under compressive strain.

[0049] More preferably, x2=0.6, and the thickness is 6 nm.

[0050] According to the preferred embodiment of the present invention, in step S9, the (Al 1-x3 Ga x3 ) y2 In 1-y2 The thickness of the P barrier layer is 5-15 nm, is not intentionally doped, 0.3≤x3≤0.6, 0.4≤y2≤0.6; and is under tensile strain.

[0051] More preferably, x3=0.35, y2=0.53, and the thickness is 8 nm.

[0052] According to the preferred embodiment of the present invention, in step S10, the Ga 1-x4 In x4 The thickness of the P second quantum well is 4-7nm and is not intentionally doped; it is under compressive strain;

[0053] Further preferably, x4=0.6, and the thickness is 6 nm. Steps S8, S9, and S10 form a superlattice multi-quantum well barrier structure, and the strained layers are grown alternately to alleviate stress effects, improve material growth quality, reduce internal losses, and decrease threshold current.

[0054] According to the preferred embodiment of the present invention, in step S11, the (Al 1-x5 Ga x5 ) y3 In 1-y3 The thickness of the waveguide layer on P is 0.05-0.15 μm, unintentionally doped, 0.05≤x5≤0.6, 0.4≤y3≤0.6, the doping source is Cp2Mg or DEZn, half doped, and the doping concentration is 3E17-7E17 atoms / cm 3 ;

[0055] More preferably, x5 changes from 0.5 to 0.05, the composition gradient growth time is 60s, y3=0.5, the thickness is 0.1μm, and the distance from the Ga 1-x4 In x4 The second quantum well of P 1-x5 Ga x5 ) y3 In 1-y3 The 0.05μm doping of the P waveguide layer has a doping concentration of 4E17 atoms / cm 3 .

[0056] According to the preferred embodiment of the present invention, in step S12, the Al 0.5 In 0.5 The doping source of the first upper confinement layer of P is Cp2Mg or DEZn, and the doping concentration is 7E17-1.5E18 atoms / cm 3 , thickness of 0.1-0.3μm;

[0057] Further preferably, the Al 0.5 In 0.5 The thickness of the first upper confinement layer is 0.15 μm, and the doping concentration is 1E18 atoms / cm 3 .

[0058] According to the preferred embodiment of the present invention, in step S13, the Ga 1-x6 In x6 The doping source of the P corrosion stop layer is Cp2Mg or DEZn, and the doping concentration is 1.2E18-3E18 atoms / cm3 , 0.4≤x8≤0.5, thickness is 8-20nm;

[0059] Further preferably, the Ga 1-x6 In x6 The thickness of the P etch stop layer is 10 nm and the doping concentration is 1.5E18 atoms / cm 3 , x8=0.47.

[0060] According to the preferred embodiment of the present invention, in step S14, the Al 0.5 In 0.5 The doping source of the second upper confinement layer of P is Cp2Mg or DEZn, and the doping concentration is 7E17-1.5E18 atoms / cm 3 , thickness of 0.5-1.2μm;

[0061] Further preferably, the Al 0.5 In 0.5 The thickness of the second upper confinement layer is 0.7 μm, and the doping concentration is 1E18 atoms / cm 3 .

[0062] According to the preferred embodiment of the present invention, in step S15, the Ga 0.5 In 0.5 The doping source of the transition layer on P is Cp2Mg or DEZn, and the doping concentration is 1.2E18-3E18 atoms / cm 3 , thickness is 20-40nm;

[0063] Further preferably, the Ga 0.5 In 0.5 The thickness of the transition layer on P is 24 nm, and the doping concentration is 2E18 atoms / cm 3 .

[0064] According to the preferred embodiment of the present invention, in step S16, the thickness of the cap layer is 0.1-0.5 μm, the doping source is CBr4 or DEZn, and the doping concentration is 4E19-1E20 atoms / cm 3 ;

[0065] More preferably, the cap layer has a thickness of 0.2 μm and a doping concentration of 7E19 atoms / cm 3 .

[0066] The beneficial effects of the present invention are:

[0067] 1. Cooling growth of the AlGaInP graded waveguide layer enables switching between different growth processes for the AlInP confinement layer and the GaInP quantum well;

[0068] 2. After the AlGaInP graded waveguide layer is grown, a strained superlattice structure is inserted to improve the material growth quality, suppress interface non-radiative recombination, thereby reducing the threshold current and improving aging characteristics.

[0069] 3. The strained superlattice uses a low Al component to reduce the diffusion of Al components between AlGaInP and GaInP quantum wells, and the impact on the lasing wavelength. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a schematic diagram of the structure of a conventional laser device;

[0071] Figure 2 It is a schematic structural diagram of the laser device of the present invention;

[0072] FIG3( a ) is a schematic diagram showing the change in operating current of the laser device structure of the present invention during the aging process at 85° C. for 24 hours;

[0073] FIG3( b ) is a schematic diagram showing the change in operating current of a conventional laser device during the aging process at 85°C for 24 hours.

[0074] 1. GaAs substrate, 2. GaAs buffer layer, 3. Ga 0.5 In 0.5 P lower transition layer, 4, Al 0.5 In 0.5 P lower limiting layer, 5, (Al 1-x1 Ga x1 ) y1 In 1-y1 P lower waveguide layer, 6, (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice, 7, Ga 1-x2 In x2 P first quantum well, 8, (Al 1-x3 Ga x3 ) y2 In 1-y2 P barrier layer, 9, Ga 1-x4 In x4 P second quantum well, 10, (Al 1- x5 Ga x5 ) y3 In 1-y3 P upper waveguide layer, 11, Al 0.5 In 0.5 P first upper confinement layer, 12, Ga 1-x6In x6 P corrosion stop layer, 13, Al 0.5 In 0.5 P second upper confinement layer, 14, Ga 0.5 In 0.5 P upper transition layer, 15, GaAs cap layer. DETAILED DESCRIPTION

[0075] The present invention will be further defined below with reference to the accompanying drawings and embodiments, but is not limited thereto.

[0076] Example 1

[0077] An AlGaInP red light semiconductor laser device with a strained superlattice structure, such as Figure 2 As shown, from bottom to top, it includes GaAs substrate 1 (substrate angle 6-15°), GaAs buffer layer 2, GaAs 0.5 In 0.5 P lower transition layer 3, Al 0.5 In 0.5 P lower confinement layer 4, (Al 1-x1 Ga x1 ) y1 In 1-y1 P lower waveguide layer 5, (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice 6, Ga 1-x2 In x2 P first quantum well 7, (Al 1-x3 Ga x3 ) y2 In 1-y2 P barrier layer 8, Ga 1-x4 In x4 P second quantum well 9, (Al 1- x5 Ga x5 ) y3 In 1-y3 P upper waveguide layer 10, Al 0.5 In 0.5 P first upper confinement layer 11, Ga 1-x6 In x6 P corrosion stop layer 12, Al 0.5 In 0.5 P second upper confinement layer 13, Ga 0.5 In 0.5 P upper transition layer 14 and GaAs cap layer 15;

[0078] Among them, 0.05≤x1≤0.6, 0.4≤y1≤0.6; 0.5≤x2≤0.7; 0.3≤x3≤0.6, 0.4≤y2≤0.6; 0.5≤x4≤0.7; 0.05≤x5≤0.6, 0.4≤y3≤0.6; 0.4≤x6≤0.5; 0.25≤a1≤0.4, 0.4≤b1≤0.45; 0.55≤b2≤0.6.

[0079] The low Al content reduces the diffusion of Al between the AlGaInP and GaInP quantum wells, which affects the lasing wavelength. The Al content a1 in the superlattice remains unchanged, while b1 is greater than 0.5 and b2 is less than 0.5. The combined growth of tensile and compressive strain improves material growth quality and suppresses interfacial non-radiative recombination.

[0080] Figure 1 It is a schematic diagram of the structure of a conventional laser device. By comparing the structures, it can be seen that in this embodiment, after changing the growth process conditions of the lower waveguide layer, multiple pairs of (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice 6 improves material growth quality and suppresses interface non-radiative recombination, thereby reducing threshold current and improving aging characteristics. At the same time, it adopts a low Al component to reduce the impact of Al component diffusion on GaInP lasing wavelength.

[0081] Example 2

[0082] The method for preparing the AlGaInP red light semiconductor laser device with a strained superlattice structure described in Example 1 comprises the following steps:

[0083] S1, placing the GaAs substrate 1 in the growth chamber of the MOCVD equipment, heating the H2 environment to 720±10°C and baking, and introducing AsH3 to perform surface heat treatment on the GaAs substrate 1;

[0084] S2, slowly lowering the temperature to 680±10°C at a rate of no more than 30°C / min, continuing to introduce TMGa and AsH3 to grow a GaAs buffer layer 2 on the GaAs substrate 1; the purpose is to prevent defects from propagating from the substrate into the confinement layer, provide a fresh growth interface, and improve the quality of material growth;

[0085] S3, the temperature is maintained at 680±10°C, the growth is paused on the GaAs buffer layer 2, PH3 is introduced, and the growth pause is achieved by suspending the V group source (99.9999% AsH3) and the III group source (TMGa) for 3-30 seconds to deplete the As atoms in the growth chamber of the MOCVD equipment;

[0086] S4, the temperature is maintained at 680±10℃, TMGa, TMIn and PH3 are introduced, and Ga is grown on the GaAs buffer layer 2. 0.5 In 0.5 P lower transition layer 3; the purpose is to reduce the band gap mutation and increase the electron migration rate;

[0087] S5, the temperature is slowly changed to 700±10℃, the heating rate is not higher than 60℃ / min, TMAl, TMIn, TMGa and PH3 are introduced, and Ga 0.5 In 0.5 n-type Al is grown on the P lower transition layer 3 0.5 In 0.5 P lower confinement layer 4;

[0088] S6, the temperature is slowly changed to 650±10℃, the cooling rate is not higher than 60℃ / min, TMAl, TMIn, TMGa and PH3 are introduced, and the n-type Al 0.5 In 0.5 The growth of the P lower confinement layer 4 (Al 1-x1 Ga x1 ) y1 In 1-y1 P lower waveguide layer 5;

[0089] S7, the temperature is maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and (Al 1-x1 Ga x1 ) y1 In 1-y1 The P lower waveguide layer 5 is grown on (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strain superlattice 6, by changing the flow of TMAl and TMGa, the flow of TMIn remains unchanged, the ratio of Al and Ga remains unchanged, and the low Al component is maintained, while the In ratio is adjusted to achieve composition change, thereby achieving tensile strain and compressive strain (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga1-a1 ) b2 In 1-b2 P strained superlattice 6 growth;

[0090] S8, the temperature is maintained at 650±10℃, TMIn, TMGa and PH3 are continuously introduced, and (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 GaN growth on P strained superlattice 6 1-x2 In x2 P first quantum well 7;

[0091] S9, the temperature is maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and Ga 1-x2 In x2 P first quantum well 7 is grown (Al 1-x3 Ga x3 ) y2 In 1-y2 P barrier layer 8;

[0092] S10, the temperature is maintained at 650±10℃, TMIn, TMGa and PH3 are continuously introduced, and (Al 1-x3 Ga x3 ) y2 In 1-y2 Ga is grown on the P barrier layer 8 1-x4 In x4 P second quantum well 9;

[0093] S11, the temperature is slowly changed to 700±10℃, the heating rate is not higher than 60℃ / min, and TMAl, TMIn, TMGa and PH3 are continuously introduced. 1-x4 In x4 P second quantum well 9 is grown (Al 1-x5 Ga x5 ) y3 In 1-y3 The waveguide layer 10 on P; a too high heating rate will cause great damage to the equipment and affect the stress release caused by slight mismatch during the growth process, so the heating and cooling rates are generally not too fast.

[0094] S12, the temperature is maintained at 700±10℃, TMAl, TMIn and PH3 are continuously introduced, and (Al 1-x5 Ga x5 ) y3 In 1-y3 P-type Al is grown on the P upper waveguide layer 100.5 In 0.5 P first upper confinement layer 11;

[0095] S13, the temperature is kept at 700±10℃, TMGa, TMIn and PH3 are continuously introduced, and the P-type Al 0.5 In 0.5 P-type GaN is grown on the first upper confinement layer 11. 1-x6 In x6 P corrosion stop layer 12;

[0096] S14, the temperature is kept at 700±10℃, TMAl, TMIn and PH3 are continuously introduced, and the P-type Ga 1-x6 In x6 P-type Al is grown on the P etching stop layer 12 0.5 In 0.5 P second upper confinement layer 13;

[0097] S15, the temperature is gradually changed to 680±10℃, the cooling rate is not higher than 60℃ / min, TMIn, TMGa and AsH3 are introduced, and the P-type Al 0.5 In 0.5 The second upper confinement layer 13 grows Ga 0.5 In 0.5 P upper transition layer 14;

[0098] S16, lower the temperature to 540±10℃, with the cooling rate not exceeding 40℃ / min, and continue to introduce TMGa and AsH3. 0.5 In 0.5 A GaAs cap layer 15 is grown on the P upper transition layer 14 .

[0099] Example 3

[0100] The method for preparing the AlGaInP red semiconductor laser device with a strained superlattice structure according to Example 2 is different in that:

[0101] In step S6, the cooling rate is 40°C / min. If the cooling rate is too fast, it may cause a mismatch due to the difference in In incorporation.

[0102] In step S7, in (Al 1-x1 Ga x1 ) y1 In 1-y1 The P lower waveguide layer 5 is grown on (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2P strained superlattice 6, the specific implementation process is:

[0103] First, the TMIn flow rate is fixed, and the flow rate is greater than the matching flow rate during the growth of Al#1 and Ga#1 to form tensile strain;

[0104] Then, turn off Al#1 and Ga#1, switch to Al#2 and Ga#2 growth, the flow rate is less than the matching flow rate, forming a compressive strain material; alternating growth, thus forming tensile strain and compressive strain (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice6.

[0105] In step S7, (A1 a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strain superlattice 6, where 0.25≤a1≤0.4, 0.4≤b1≤0.45, compressive strain thickness 13-23 angstroms; 0.55≤b2≤0.6, tensile strain thickness 17-26 angstroms, a total of 3-7 pairs.

[0106] In step S2, the doping source of the GaAs buffer layer 2 is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm 3 , thickness of 0.1-0.3μm;

[0107] In step S4, Ga 0.5 In 0.5 The doping source of the P lower transition layer 3 is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm 3 , thickness of 0.1-0.3μm;

[0108] In step S5, A1 0.5 In 0.5 The doping source of the P lower confinement layer 4 is Si2H6, and the doping concentration is 7E17-2E18 atoms / cm 3 , thickness of 0.7-1.5μm;

[0109] In step S6, (A1 1-x1 Ga x1 ) y1 In 1-y1The thickness of the P lower waveguide layer 5 is 0.05-0.15 μm, it is not intentionally doped, 0.05≤x1≤0.6, 0.4≤y1≤0.6;

[0110] In step S8, Ga 1-x2 In x2 The thickness of the P first quantum well 7 is 4-7 nm, and it is not intentionally doped; it is under compressive strain.

[0111] In step S9, (A1 1-x3 Ga x3 ) y2 In 1-y2 The thickness of the P barrier layer 8 is 5-15 nm, is not intentionally doped, 0.3≤x3≤0.6, 0.4≤y2≤0.6; and is subjected to tensile strain.

[0112] In step S10, Ga 1-x4 In x4 The thickness of the P second quantum well 9 is 4-7nm and is not intentionally doped; it is under compressive strain;

[0113] In step S11, (A1 1-x5 Ga x5 ) y3 In 1-y3 The thickness of the waveguide layer 10 on P is 0.05-0.15 μm, and it is not intentionally doped. 0.05≤x5≤0.6, 0.4≤y3≤0.6, and the doping source is Cp2Mg or DEZn, half doped, with a doping concentration of 3E17-7E17 atoms / cm 3 ;

[0114] In step S12, A1 0.5 In 0.5 The doping source of the first upper confinement layer 11 is Cp2Mg or DEZn, and the doping concentration is 7E17-1.5E18 atoms / cm 3 , thickness of 0.1-0.3μm;

[0115] In step S13, Ga 1-x6 In x6 The doping source of the P etch stop layer 12 is Cp2Mg or DEZn, and the doping concentration is 1.2E18-3E18 atoms / cm 3 , 0.4≤x8≤0.5, thickness is 8-20nm;

[0116] In step S14, A1 0.5 In 0.5 The doping source of the second upper confinement layer 13 is Cp2Mg or DEZn, and the doping concentration is 7E17-1.5E18 atoms / cm 3 , thickness of 0.5-1.2μm;

[0117] In step S15, Ga 0.5 In 0.5 The doping source of the P upper transition layer 14 is Cp2Mg or DEZn, and the doping concentration is 1.2E18-3E18 atoms / cm 3 , thickness is 20-40nm;

[0118] In step S16, the thickness of the cap layer is 0.1-0.5 μm, the doping source is CBr4 or DEZn, and the doping concentration is 4E19-1E20 atoms / cm 3 ;

[0119] Example 4

[0120] The method for preparing the AlGaInP red semiconductor laser device with a strained superlattice structure according to Example 2 is different in that:

[0121] In step S7, a1=0.35, b1=0.4, the compressive strain thickness is 17 angstroms, b2=0.6, the tensile strain thickness is 23 angstroms, and there are 5 pairs in total.

[0122] Among them, a1 uses a low Al component to reduce the impact of Al component diffusion between AlGaInP and GaInP quantum wells on the lasing wavelength; by adjusting the In component ratio, a combined superlattice of compressive strain and tensile strain is realized, the material growth quality is optimized, the impact of process switching on the subsequent quantum well growth is avoided, the interface scattering effect is reduced, and the threshold current density is reduced.

[0123] In step S2, the thickness of the GaAs buffer layer 2 is 0.2 μm and the doping concentration is 2E18 atoms / cm 3 .

[0124] In step S4, Ga 0.5 In 0.5 The thickness of the P lower transition layer 3 is 0.2 μm, and the doping concentration is 4E18 atoms / cm 3 .

[0125] In step S5, A1 0.5 In 0.5 The thickness of the P lower confinement layer 4 is 1.2 μm, and the doping concentration is 1E18 atoms / cm 3 .

[0126] In step S6, x1 is gradually changed from 0.05 to 0.5, the composition gradient growth time is 60s, y1 = 0.5, and the thickness is 0.1μm. The temperature in the waveguide layer is lowered and V / III is adjusted to achieve the optimal growth process switching between AlInP and GaInP.

[0127] In step S8, x2=0.6, and the thickness is 6 nm.

[0128] In step S9 , x3=0.35, y2=0.53, and the thickness is 8 nm.

[0129] In step S10, x4=0.6, and the thickness is 6nm. Steps S8, S9, and S10 form a superlattice multi-quantum well barrier structure, and the strained layers are grown alternately to alleviate stress effects, improve material growth quality, reduce internal losses, and decrease threshold current.

[0130] In step S11, x5 is gradually changed from 0.5 to 0.05, the composition gradient growth time is 60s, y3=0.5, the thickness is 0.1μm, and the distance from Ga 1-x4 In x4 The second quantum well 9 of P 1-x5 Ga x5 ) y3 In 1-y3 The 0.05 μm doping of the waveguide layer 10 on P is performed with a doping concentration of 4E17 atoms / cm 3 .

[0131] In step S12, A1 0.5 In 0.5 The thickness of the first upper confinement layer 11 is 0.15 μm, and the doping concentration is 1E18 atoms / cm 3 .

[0132] In step S13, Ga 1-x6 In x6 The thickness of the P etching stop layer 12 is 10 nm and the doping concentration is 1.5E18 atoms / cm 3 , x8=0.47.

[0133] In step S14, A1 0.5 In 0.5 The thickness of the second upper confinement layer 13 is 0.7 μm, and the doping concentration is 1E18 atoms / cm 3 .

[0134] In step S15, Ga 0.5 In 0.5 The thickness of the P upper transition layer 14 is 24 nm, and the doping concentration is 2E18 atoms / cm 3 .

[0135] In step S16, the thickness of the cap layer is 0.2 μm and the doping concentration is 7E19 atoms / cm 3 .

[0136] Figure 3(a) shows the change in operating current during aging at 85°C for 24 hours for the laser device structure of this embodiment; Figure 3(b) shows the change in operating current during aging at 85°C for 24 hours for a conventional laser device structure. In Figures 3(a) and 3(b), the horizontal axis represents the aging time in hours, and the vertical axis represents the operating current at an output power of 5mW in mA. The comparison results show that the operating current of the laser device of this embodiment changes little during aging, and the TO threshold current is lower than that of the conventional structure (operating current at the onset of aging). This indicates that the insertion of a strained superlattice structure in the present invention helps reduce the threshold current and improve aging characteristics.

Claims

1. An AlGaInP red light semiconductor laser device with a strained superlattice structure, characterized in that: From bottom to top, it includes GaAs substrate, GaAs buffer layer, Ga 0.5 In 0.5 P lower transition layer, Al 0.5 In 0.5 P lower confinement layer, (Al 1-x1 Ga x1 ) y1 In 1-y1 P lower waveguide layer, (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice, Ga 1-x2 In x2 P first quantum well, (Al 1-x3 Ga x3 ) y2 In 1-y2 P barrier layer, Ga 1-x4 In x4 P second quantum well, (Al 1-x5 Ga x5 ) y3 In 1-y3 P upper waveguide layer, Al 0.5 In 0.5 P first upper confinement layer, Ga 1-x6 In x6 P corrosion stop layer, Al 0.5 In 0.5 P second upper confinement layer, Ga 0.5 In 0.5 P upper transition layer and GaAs cap layer; Among them, 0.05≤x1≤0.6, 0.4≤y1≤0.6; 0.5≤x2≤0.7; 0.3≤x3≤0.6, 0.4≤y2≤0.6; 0.5≤x4≤0.7; 0.05≤x5≤0.6, 0.4≤y3≤0.6; 0.4≤x6≤0.5; 0.25≤a1≤0.4, 0.4≤b1≤0.45; 0.55≤b2≤0.6; a1 is less than 0.4, b1 is greater than 0.5, and b2 is less than 0.

5.

2. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 1, characterized in that: The following steps are involved: S1, placing the GaAs substrate in a growth chamber of an MOCVD device, heating the H2 environment to 720±10°C, and introducing AsH3 to perform surface heat treatment on the GaAs substrate; S2, slowly lowering the temperature to 680±10° C. at a cooling rate of no more than 30° C. / min, continuing to introduce TMGa and AsH 3 to grow the GaAs buffer layer on the GaAs substrate; S3, maintaining the temperature at 680±10°C, pausing the growth on the GaAs buffer layer, introducing PH3, and achieving a growth pause by suspending the V group source and the III group source for 3-30 seconds to deplete the As atoms in the growth chamber of the MOCVD equipment; S4, the temperature is maintained at 680±10°C, TMGa, TMIn and PH3 are introduced, and the GaAs buffer layer is grown on the GaAs buffer layer. 0.5 In 0.5 P lower transition layer; S5, the temperature is slowly changed to 700±10℃, the heating rate is not higher than 60℃ / min, TMAl, TMIn, TMGa and PH3 are introduced, and the Ga 0.5 In 0.5 The Al is grown on the P lower transition layer. 0.5 In 0.5 P lower limiting layer; S6, the temperature is slowly changed to 650±10℃, the cooling rate is not higher than 60℃ / min, TMAl, TMIn, TMGa and PH3 are introduced, and the Al 0.5 In 0.5 The (Al 1-x1 Ga x1 ) y1 In 1-y1 P lower waveguide layer; S7, the temperature is maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and the 1-x1 Ga x1 ) y1 In 1-y1 The (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strain superlattice, by changing the flow of TMAl and TMGa, the flow of TMIn remains unchanged, the ratio of Al and Ga remains unchanged, and the low Al component is maintained, while the In ratio is adjusted to achieve component changes, thereby achieving tensile strain and compressive strain (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice growth; S8, the temperature is maintained at 650±10℃, TMIn, TMGa and PH3 are continuously introduced, and the (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 The GaN-P strained superlattice is grown on the 1-x2 In x2 P first quantum well; S9, the temperature is maintained at 650±10℃, TMAl, TMIn, TMGa and PH3 are introduced, and the Ga 1-x2 In x2 The (Al 1-x3 Ga x3 ) y2 In 1-y2 P barrier layer; S10, the temperature is maintained at 650±10℃, TMIn, TMGa and PH3 are continuously introduced, and in the (Al 1-x3 Ga x3 ) y2 In 1-y2 The Ga 1-x4 In x4 P second quantum well; S11, the temperature is slowly changed to 700±10℃, the heating rate is not higher than 60℃ / min, and TMAl, TMIn, TMGa and PH3 are continuously introduced. 1-x4 In x4 The (Al 1-x5 Ga x5 ) y3 In 1-y3 P upper waveguide layer; S12, the temperature is maintained at 700±10℃, TMAl, TMIn and PH3 are continuously introduced, and the (Al 1-x5 Ga x5 ) y3 In 1-y3 The Al 0.5 In 0.5 P first upper confinement layer; S13, the temperature is maintained at 700±10℃, TMGa, TMIn and PH3 are continuously introduced, and the Al 0.5 In 0.5 The P-type Ga 1-x6 In x6 P corrosion stop layer; S14, the temperature is kept at 700±10℃, TMAl, TMIn and PH3 are continuously introduced, and the P-type Ga 1-x6 In x6 The P-type Al is grown on the P corrosion stop layer. 0.5 In 0.5 P second upper confinement layer; S15, the temperature is gradually changed to 680±10℃, the cooling rate is not higher than 60℃ / min, TMIn, TMGa and AsH3 are introduced, and the P-type Al 0.5 In 0.5 The second upper confinement layer of P is grown on the Ga 0.5 In 0.5 P upper transition layer; S16, lower the temperature to 540±10℃, with the cooling rate not exceeding 40℃ / min, continue to introduce TMGa and AsH3, and 0.5 In 0.5 A GaAs cap layer is grown on the P upper transition layer.

3. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 2, characterized in that: In step S7, in the (Al 1-x1 Ga x1 ) y1 In 1-y1 The (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice, the specific implementation process is: First, the TMIn flow rate is fixed, and the flow rate is greater than the matching flow rate during the growth of Al#1 and Ga#1 to form tensile strain; Then, turn off Al#1 and Ga#1, switch to Al#2 and Ga#2 growth, the flow rate is less than the matching flow rate, forming a compressive strain material; alternating growth, thus forming tensile strain and compressive strain (Al a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strained superlattice.

4. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 2, wherein: In step S7, the (A1 a1 Ga 1-a1 ) b1 In 1-b1 P / (Al a1 Ga 1-a1 ) b2 In 1-b2 P strain superlattice, where 0.25≤a1≤0.4, 0.4≤b1≤0.45, and compressive strain thickness 13-23 angstroms; 0.55≤b2≤0.6, tensile strain thickness 17-26 angstroms, 3-7 pairs in total.

5. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 4, characterized in that: a1=0.35, b1=0.4, compressive strain thickness 17 angstroms, b2=0.6, tensile strain thickness 23 angstroms, a total of 5 pairs.

6. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 2, wherein: In step S6, the cooling rate is 40°C / min; In step S2, the doping source of the GaAs buffer layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm 3 , thickness is 0.1-0.3μm.

7. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 6, characterized in that: The thickness of the GaAs buffer layer is 0.2 μm and the doping concentration is 2E18 atoms / cm 3 .

8. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 2, wherein: In step S4, the Ga 0.5 In 0.5 The doping source of the P lower transition layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm 3 , thickness is 0.1-0.3μm.

9. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 8, characterized in that: The Ga 0.5 In 0.5 The thickness of the P lower transition layer is 0.2 μm, and the doping concentration is 4E18 atoms / cm 3 .

10. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 2, wherein: In step S5, the Al 0.5 In 0.5 The doping source of the P lower confinement layer is Si2H6, and the doping concentration is 7E17-2E18 atoms / cm 3 , thickness is 0.7-1.5μm.

11. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 10, characterized in that: The Al 0.5 In 0.5 The thickness of the P lower confinement layer is 1.2 μm, and the doping concentration is 1E18 atoms / cm 3 ; In step S6, the (A1 1-x1 Ga x1 ) y1 In 1-y1 The thickness of the P lower waveguide layer is 0.05-0.15 μm, is not intentionally doped, and has a value of 0.05≤x1≤0.6 and 0.4≤y1≤0.

6.

12. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 10, characterized in that: x1 gradually changes from 0.05 to 0.5, the component gradient growth time is 60s, y1=0.5, and the thickness is 0.1μm.

13. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 2, wherein: In step S8, the Ga 1-x2 In x2 The thickness of the P first quantum well is 4-7nm and is not intentionally doped.

14. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 13, characterized in that: x2 = 0.6, thickness is 6nm; In step S9, the (Al 1-x3 Ga x3 ) y2 In 1-y2 The thickness of the P barrier layer is 5-15 nm, is not intentionally doped, and is 0.3≤x3≤0.6 and 0.4≤y2≤0.

6.

15. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 13, characterized in that: x3=0.35, y2=0.53, thickness is 8nm.

16. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to claim 2, wherein: In step S10, the Ga 1-x4 In x4 The thickness of the P second quantum well is 4-7nm and is not intentionally doped; In step S11, the (Al 1-x5 Ga x5 ) y3 In 1-y3 The thickness of the waveguide layer on P is 0.05-0.15 μm, unintentionally doped, 0.05≤x5≤0.6, 0.4≤y3≤0.6, the doping source is Cp2Mg or DEZn, half doped, and the doping concentration is 3E17-7E17 atoms / cm 3 ; In step S12, the Al 0.5 In 0.5 The doping source of the first upper confinement layer of P is Cp2Mg or DEZn, and the doping concentration is 7E17-1.5E18 atoms / cm 3 , thickness of 0.1-0.3μm; In step S13, the Ga 1-x6 In x6 The doping source of the P corrosion stop layer is Cp2Mg or DEZn, and the doping concentration is 1.2E18-3E18 atoms / cm 3 , 0.4≤x8≤0.5, thickness is 8-20nm; In step S14, the Al 0.5 In 0.5 The doping source of the second upper confinement layer of P is Cp2Mg or DEZn, and the doping concentration is 7E17-1.5E18 atoms / cm 3 , thickness of 0.5-1.2μm; In step S15, the Ga 0.5 In 0.5 The doping source of the transition layer on P is Cp2Mg or DEZn, and the doping concentration is 1.2E18-3E18 atoms / cm 3 , thickness is 20-40nm; In step S16, the thickness of the cap layer is 0.1-0.5 μm, the doping source is CBr4 or DEZn, and the doping concentration is 4E19-1E20 atoms / cm 3 .

17. The method for preparing an AlGaInP red light semiconductor laser device with a strained superlattice structure according to any one of claims 2 to 16, characterized in that: In step S10, x4=0.6, thickness is 6 nm; In step S11, x5 is gradually changed from 0.5 to 0.05, the composition gradient growth time is 60s, y3=0.5, the thickness is 0.1μm, and the distance from the Ga 1-x4 In x4 The second quantum well of P 1-x5 Ga x5 ) y3 In 1-y3 The 0.05μm doping of the P waveguide layer has a doping concentration of 4E17 atoms / cm 3 ; In step S12, the Al 0.5 In 0.5 The thickness of the first upper confinement layer is 0.15 μm, and the doping concentration is 1E18 atoms / cm 3 ; In step S13, the Ga 1-x6 In x6 The thickness of the P etch stop layer is 10 nm and the doping concentration is 1.5E18 atoms / cm 3 , x8=0.47; In step S14, the Al 0.5 In 0.5 The thickness of the second upper confinement layer of P is 0.7 μm, and the doping concentration is 1E18 atoms / cm 3 ; In step S15, the Ga 0.5 In 0.5 The thickness of the transition layer on P is 24 nm, and the doping concentration is 2E18 atoms / cm 3 ; In step S16, the thickness of the cap layer is 0.2 μm and the doping concentration is 7E19 atoms / cm 3 .

Images