AlGaInPAs-based light emitting diode and preparation method thereof

Abstract

The invention discloses an AlGaInPAs-based light emitting diode and a preparation method thereof. The preparation method comprises the following steps: providing a composite substrate; sequentially growing an N-type semiconductor layer, an active layer and a P-type semiconductor layer on the composite substrate to obtain an AlGaInPAs-based light emitting diode epitaxial wafer; at least removing the composite substrate of the AlGaInPAs-based light emitting diode epitaxial wafer, and respectively depositing an N electrode and a P electrode on the N-type semiconductor layer and the P-type semiconductor layer to obtain an AlGaInPAs-based light emitting diode; wherein the materials of the N-type semiconductor layer, the active layer and the P-type semiconductor layer are AlxGayIn (1-x-y) PZAs (1-z), 0 < = x < = 1, 0 < = y < = 1, 0 < = x + y < = 1, and 0 < = z < = 1; the composite substrate is formed by bonding a sapphire substrate and a GaAs substrate. According to the invention, the mechanical strength of the composite substrate can be improved, the thickness of the GaAs substrate can be reduced, and the cost can be saved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an AlGaInPAs-based light emitting diode and a preparation method thereof. Background Art

[0002] The AlGaInPAs-based LED epitaxial wafer structure usually includes a GaAs substrate and an N-type semiconductor layer, an active layer, and a P-type semiconductor layer deposited in sequence. When used for the epitaxy of AlGaInPAs materials, GaAs substrates have the advantages of high lattice matching, high electron mobility, and good process compatibility, but their mechanical strength is weak and they are prone to cracking and breaking during mass production; secondly, the production technology threshold of GaAs substrates is high, resulting in relatively high prices. GaAs substrates are usually peeled off or thinned in subsequent chip manufacturing processes. In order to meet the mechanical strength requirements of epitaxial growth, the thickness of GaAs substrates used for AlGaInPAs epitaxial growth is usually about 360μm. Although thinning the thickness of the GaAs substrate can reduce costs, it will increase the probability of cracking and breaking during epitaxial high-temperature growth. Although sapphire materials have the advantages of high mechanical strength, good chemical stability, and low price and cost, their crystal structure and lattice constant are very different from those of AlGaInPAs materials, making it difficult to directly use them as substrate materials for epitaxial growth of AlGaInPAs structures. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an AlGaInPAs-based light emitting diode and a preparation method thereof, which can improve the mechanical strength of the composite substrate while reducing the thickness of the GaAs substrate and saving costs.

[0004] In order to solve the above problems, the present invention discloses a method for preparing an AlGaInPAs-based light-emitting diode, comprising the following steps:

[0005] providing a composite substrate;

[0006] An N-type semiconductor layer, an active layer and a P-type semiconductor layer are sequentially grown on the composite substrate to obtain an AlGaInPAs-based light-emitting diode epitaxial wafer;

[0007] At least the composite substrate of the AlGaInPAs-based light-emitting diode epitaxial wafer is removed, and an N electrode and a P electrode are deposited on the N-type semiconductor layer and the P-type semiconductor layer respectively to obtain an AlGaInPAs-based light-emitting diode;

[0008] The materials of the N-type semiconductor layer, the active layer and the P-type semiconductor layer are Al x Ga y In (1-x-y) P Z As (1-z), 0≤x≤1, 0≤y≤1, 0≤x+y≤1, 0≤z≤1;

[0009] The composite substrate is formed by bonding a sapphire substrate and a GaAs substrate.

[0010] As an improvement of the above technical solution, the thickness of the sapphire substrate is 200 μm to 2000 μm, and the thickness of the GaAs substrate is 50 μm to 350 μm.

[0011] As an improvement of the above technical solution, the thickness of the sapphire substrate is 200 μm to 600 μm, and the thickness of the GaAs substrate is 150 μm to 350 μm.

[0012] As an improvement of the above technical solution, the sapphire substrate and the GaAs substrate are bonded via a SiO2 bonding layer, and the thickness of the SiO2 bonding layer is 1 μm to 10 μm.

[0013] As an improvement of the above technical solution, the sapphire substrate is provided with through holes penetrating the upper and lower surfaces of the sapphire substrate.

[0014] As an improvement of the above technical solution, the sapphire substrate and the GaAs substrate are bonded by adopting the following steps:

[0015] Preparing a first SiO2 bonding layer on the upper surface of the sapphire substrate, with a thickness of 1 μm to 4 μm;

[0016] Preparing a second SiO2 bonding layer on the lower surface of the GaAs substrate, with a thickness of 1 μm to 4 μm;

[0017] Grinding and polishing the first SiO2 bonding layer and the second SiO2 bonding layer;

[0018] The first SiO2 bonding layer and the second SiO2 bonding layer after grinding and polishing are aligned, and the SiO2 bonding layer is formed after hot pressing and bonding.

[0019] As an improvement of the above technical solution, the bonding temperature of the thermal compression bonding is 300° C. to 500° C., and the bonding pressure is 0.1 MPa to 0.4 MPa.

[0020] As an improvement of the above technical solution, the N-type semiconductor layer is prepared by the following steps: an N-type buffer layer, an N-type cutoff layer, an N-type contact layer, an N-type extension layer, an N-type electron layer and an N-type electron blocking layer are sequentially grown on the composite substrate;

[0021] The P-type semiconductor layer is prepared by adopting the following steps: a P-type hole blocking layer, a P-type hole layer, a P-type transition layer, a P-type window layer and a P-type contact layer are grown in sequence on the active layer.

[0022] As an improvement of the above technical solution, the composite substrate, the N-type buffer layer and the N-type cut-off layer of the AlGaInPAs-based light-emitting diode epitaxial wafer are removed.

[0023] Correspondingly, the present invention also discloses an AlGaInPAs-based light-emitting diode, which is prepared by the above-mentioned preparation method.

[0024] The implementation of the present invention has the following beneficial effects: the present invention epitaxially grows AlGaInPAs material on a composite substrate formed by bonding a sapphire substrate and a GaAs substrate, which can ensure lattice matching between the GaAs substrate and the AlGaInPAs epitaxial layer material, and the growth quality of the epitaxial layer material is good. The sapphire substrate can also improve the mechanical strength of the composite substrate, and accordingly, the thickness of the GaAs substrate can be reduced, saving costs, and ultimately achieving high-quality, low-cost manufacturing of AlGaInPAs-based light-emitting diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of an AlGaInPAs-based light-emitting diode epitaxial wafer provided by the present invention;

[0026] Figure 2 It is a schematic structural diagram of a sapphire substrate provided by the present invention and provided with a first SiO2 bonding layer;

[0027] Figure 3 It is a schematic structural diagram of a GaAs substrate provided by the present invention and provided with a second SiO2 bonding layer;

[0028] Figure 4 is a schematic structural diagram of a composite substrate provided by the present invention;

[0029] Figure 5 The present invention provides a process flow chart for preparing an AlGaInPAs-based light-emitting diode. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0031] See also Figure 1 and Figure 5 The present invention provides a method for preparing an AlGaInPAs-based light-emitting diode, comprising the following steps:

[0032] S100, providing a composite substrate; specifically, the composite substrate 100 is formed by bonding a sapphire substrate 101 and a GaAs substrate 103. In some embodiments, the thickness of the sapphire substrate 101 is 200μm to 2000μm, and is exemplarily 300μm, 500μm, 800μm, 1000μm, 1500μm or 1800μm, but not limited thereto. If the thickness of the sapphire substrate 101 is too small, it is not conducive to improving the mechanical strength of the composite substrate, and if the thickness of the sapphire substrate 101 is too large, it will cause waste of materials. Preferably, the thickness of the sapphire substrate 101 is 200μm to 600μm. The thickness of the GaAs substrate 103 is 50μm to 350μm, and is exemplarily 60μm, 80μm, 150μm, 200μm, 250μm or 300μm, but not limited thereto. If the thickness of the GaAs substrate 103 is too small, it is not conducive to matching with the subsequent epitaxial material. If the thickness of the GaAs substrate 103 is too large, it will increase the cost. Preferably, the thickness of the GaAs substrate is 150μm to 350μm. The substrate of the conventional AlGaInPAs-based light-emitting diode epitaxial wafer is a GaAs substrate. Although GaAs and AlGaInPAs-based epitaxial materials have a high degree of matching, in order to meet the mechanical strength requirements of epitaxial growth, the thickness of the general GaAs substrate is about 360μm. However, the cost of GaAs is relatively high. Although thinning the substrate can reduce the cost, the mechanical strength is difficult to meet the requirements of epitaxial growth, which ultimately leads to an increase in the probability of cracks and fragments during epitaxial high-temperature growth. The present invention composites a sapphire substrate with high mechanical strength and a GaAs substrate with a high degree of matching with the epitaxial layer material to obtain a composite substrate that can significantly improve the quality of epitaxy.

[0033] In one embodiment, the sapphire substrate 101 is provided with a through hole 111 penetrating the upper and lower surfaces of the sapphire substrate 101. In the subsequent preparation process, the composite substrate 100 needs to be removed, and the provision of the through hole 111 can accelerate the etching rate of the GaAs substrate 103, thereby improving the preparation efficiency.

[0034] In one embodiment, the sapphire substrate 101 and the GaAs substrate 103 are bonded via a SiO2 bonding layer 102, and the thickness of the SiO2 bonding layer 102 is 1 μm to 10 μm, and is exemplarily 2 μm, 4 μm, 5 μm, 6 μm, 8 μm or 9 μm, but is not limited thereto.

[0035] Specifically, the sapphire substrate and the GaAs substrate are bonded by the following steps:

[0036] S101, preparing a first SiO2 bonding layer 102a on the upper surface of the sapphire substrate 101, with a thickness of 1 μm to 4 μm; specifically, the first SiO2 bonding layer 102a can be prepared by evaporation, chemical vapor deposition, etc.;

[0037] S102, preparing a second SiO2 bonding layer 102b on the lower surface of the GaAs substrate 103, with a thickness of 1 μm to 4 μm; specifically, the second SiO2 bonding layer 102b can be prepared by evaporation, chemical vapor deposition, etc.;

[0038] S103, grinding and polishing the first SiO2 bonding layer 102a and the second SiO2 bonding layer 102b; the thickness of the first SiO2 bonding layer 102a after grinding and polishing is 0.6 μm to 3 μm, and the thickness of the second SiO2 bonding layer 102b after grinding and polishing is 0.6 μm to 3 μm;

[0039] S104, aligning the first SiO2 bonding layer 102a and the second SiO2 bonding layer 102b after grinding and polishing, and performing thermocompression bonding to form the SiO2 bonding layer 102. Specifically, the thermocompression bonding has a bonding temperature of 300°C to 500°C and a bonding pressure of 0.1MPa to 0.4MPa.

[0040] In one embodiment, the process further includes grinding, rough polishing and fine polishing the GaAs surface of the composite substrate after thermal compression bonding to obtain a flat and smooth surface required for epitaxial growth of AlGaInPAs.

[0041] S200, sequentially growing an N-type semiconductor layer 200, an active layer 300 and a P-type semiconductor layer 400 on the composite substrate 100 to obtain an AlGaInPAs-based light-emitting diode epitaxial wafer;

[0042] The materials of the N-type semiconductor layer 200, the active layer 300 and the P-type semiconductor layer 400 are Al x Ga y In (1-x-y) P Z As (1-z) , 0≤x≤1, 0≤y≤1, 0≤x+y≤1, 0≤z≤1;

[0043] Specifically, the following steps are included:

[0044] S201, depositing an N-type buffer layer on the composite substrate;

[0045] In one embodiment, the N-type buffer layer 201 is a Si-doped GaAs buffer layer, and the Si doping concentration is 1×10 19 cm -3 ~1×1021 cm -3 , with a thickness of 100nm to 400nm. The specific deposition process is: control the reaction chamber temperature to 650℃ to 700℃, the reaction chamber pressure to 40mbar to 80mbar, use TMGa as Ga source, AsH3 as As source, and Si2H6 as dopant. The Si-doped GaAs buffer layer can effectively improve the lattice defects caused by lattice mismatch and thermal mismatch between the subsequently grown epitaxial layer and the substrate.

[0046] S202, depositing an N-type cutoff layer on the N-type buffer layer;

[0047] In one embodiment, the N-type cutoff layer 202 is a Si-doped GaInP cutoff layer, and the Si doping concentration is 1×10 18 cm -3 ~1×10 20 cm -3 The thickness is 100nm~1000nm. The specific deposition process is: control the reaction chamber temperature to 650℃~750℃, the reaction chamber pressure to 40mbar~80mbar, use TMGa as Ga source, TMIn as In source, PH3 as P source, and Si2H6 as dopant.

[0048] S203, depositing an N-type contact layer on the N-type cutoff layer;

[0049] In one embodiment, the N-type contact layer 203 is a Si-doped GaAs contact layer, and the Si doping concentration is 1×10 17 cm -3 ~1×10 19 cm -3 , with a thickness of 50nm to 200nm. The specific deposition process is: control the reaction chamber temperature to 650℃ to 700℃, the reaction chamber pressure to 40mbar to 80mbar, use TMGa as the Ga source, AsH3 as the As source, and Si2H6 as the dopant. The Si-doped GaAs contact layer is used to make ohmic contact with the N electrode when the light-emitting diode chip is subsequently prepared.

[0050] S204, depositing an N-type extension layer on the N-type GaAs contact layer;

[0051] In one embodiment, the N-type extension layer 204 is a Si-doped AlGaInP extension layer, and the Si doping concentration is 1×10 16 cm -3 ~1×10 18 cm -3, with a thickness of 1μm to 4μm. The specific deposition process is: control the reaction chamber temperature to 650℃ to 700℃, the reaction chamber pressure to 50mbar to 90mbar, use TMAl as Al source, TMGa as Ga source, TMIn as In source, PH3 as P source, and Si2H6 as dopant. The Si-doped N-type expansion layer can improve the N-type current expansion capability in the light-emitting diode chip.

[0052] S205, depositing an N-type electron layer on the N-type extension layer;

[0053] In one embodiment, the N-type electron layer 205 is a Si-doped AlInP electron layer, and the Si doping concentration is 1×10 17 cm -3 ~1×10 19 cm -3 The thickness is 100nm~400nm. The specific deposition process is: control the reaction chamber temperature to 650℃~700℃, the reaction chamber pressure to 50mbar~90mbar, use TMAl as Al source, TMIn as In source, PH3 as P source, and Si2H6 as dopant.

[0054] S206, depositing an N-type electron blocking layer on the N-type electron layer;

[0055] In one embodiment, the N-type electron blocking layer 206 is an AlGaInP electron blocking layer with a thickness of 20 nm to 200 nm. The specific deposition process is: controlling the reaction chamber temperature to 650° C. to 700° C., the reaction chamber pressure to 50 mbar to 100 mbar, using TMAl as the Al source, TMGa as the Ga source, TMIn as the In source, and PH3 as the P source.

[0056] S207, depositing an active layer on the N-type electron blocking layer;

[0057] In one embodiment, the active layer 300 includes 5 to 15 alternately stacked quantum well layers and quantum barrier layers, wherein the quantum well layer is a GaInP quantum well layer with a thickness of 3 nm to 7 nm, and the quantum barrier layer is an AlGaInP quantum barrier layer with a thickness of 5 nm to 9 nm.

[0058] The specific deposition process is:

[0059] S207a, depositing a GaInP quantum well layer;

[0060] The temperature of the reaction chamber is controlled to be 620° C. to 720° C., the pressure of the reaction chamber is 50 mbar to 100 mbar, TMGa is used as the Ga source, TMIn is used as the In source, and PH3 is used as the P source.

[0061] S207b, depositing an AlGaInP quantum barrier layer;

[0062] The temperature of the reaction chamber is controlled to be 650° C. to 750° C., the pressure of the reaction chamber is 40 mbar to 80 mbar, TMAl is used as the Al source, TMGa is used as the Ga source, TMIn is used as the In source, and PH3 is used as the P source.

[0063] S207c, alternately depositing the GaInP quantum well layer and the AlGaInP quantum barrier layer.

[0064] S208, depositing a P-type hole blocking layer on the active layer;

[0065] In one embodiment, the P-type hole blocking layer 401 is an AlGaInP hole blocking layer with a thickness of 20nm to 200nm. The specific deposition process is: controlling the reaction chamber temperature to 650°C to 700°C, the reaction chamber pressure to 50mbar to 90mbar, using TMAl as the Al source, TMGa as the Ga source, TMIn as the In source, and PH3 as the P source.

[0066] S209, depositing a P-type hole layer on the P-type hole blocking layer;

[0067] In one embodiment, the P-type vacancy layer 402 is a Mg-doped AlInP vacancy layer, and the Mg doping concentration is 1×10 17 cm -3 ~1×10 19 cm -3 The thickness is 150nm to 350nm. The specific deposition process is: control the reaction chamber temperature to 600℃ to 700℃, the reaction chamber pressure to 50mbar to 90mbar, use TMAl as Al source, TMIn as In source, PH3 as P source, and CP2Mg as dopant.

[0068] S210, depositing a P-type transition layer on the P-type hole layer;

[0069] In one embodiment, the P-type transition layer 403 is a P-type AlInP transition sublayer, a P-type AlGaInP transition sublayer and a P-type GaInP transition sublayer deposited in sequence, and the Mg doping concentration of the P-type AlInP transition sublayer is 5×10 17 cm -3 ~5×10 18 cm -3 , with a thickness of 2nm to 10nm; the Mg doping concentration of the AlGaInP transition sublayer is 5×10 18 cm -3 ~5×10 19 cm -3, with a thickness of 5nm to 40nm; the Mg doping concentration of the P-type GaInP transition sublayer is 5×10 19 cm -3 ~5×10 20 cm -3 The thickness is 2nm to 10nm. The specific deposition process is: control the reaction chamber temperature to 600℃ to 700℃, the reaction chamber pressure to 50mbar to 90mbar, use TMAl as Al source, TMGa as Ga source, TMIn as In source, PH3 as P source, and CP2Mg as dopant.

[0070] S211, depositing a P-type window layer on the P-type transition layer;

[0071] In one embodiment, the P-type window layer 404 is a GaP window layer, and the Mg doping concentration may be 1×10 18 cm -3 ~1×10 21 cm -3 , with a thickness of 0.1μm to 8μm. The specific deposition process is: control the reaction chamber temperature to 660℃ to 760℃, the reaction chamber pressure to 40mbar to 80mbar, use TMGa as Ga source, PH3 as P source, and CP2Mg as Mg source.

[0072] S212, depositing a P-type contact layer on the P-type window layer;

[0073] In one embodiment, the P-type contact layer 405 is a C-doped GaP layer, and the C doping concentration is 1×10 20 cm -3 ~1×10 22 cm -3 The thickness is 50nm to 200nm. The specific deposition process is: control the reaction chamber temperature to 550℃ to 700℃, the reaction chamber pressure to 50mbar to 90mbar, use TMGa as Ga source, and PH3 as P source.

[0074] S300, removing at least the composite substrate 100 of the AlGaInPAs-based light-emitting diode epitaxial wafer, and depositing an N electrode and a P electrode on the N-type semiconductor layer 200 and the P-type semiconductor layer 400, respectively, to obtain an AlGaInPAs-based light-emitting diode;

[0075] In one embodiment, the composite substrate 100, N-type buffer layer 201 and N-type cutoff layer 202 of the AlGaInPAs-based light-emitting diode epitaxial wafer are removed, and an N electrode and a P electrode are deposited on the N-type contact layer 203 and the P-type contact layer 405 respectively to obtain an AlGaInPAs-based light-emitting diode.

[0076] The present invention will be further described below with specific embodiments:

[0077] Example 1

[0078] This embodiment provides a method for preparing an AlGaInPAs-based light-emitting diode, comprising the following steps:

[0079] S100, providing a composite substrate; the composite substrate is formed by bonding a sapphire substrate and a GaAs substrate;

[0080] Specifically, the sapphire substrate and the GaAs substrate are bonded using the following steps:

[0081] S101, vapor-depositing a first SiO2 bonding layer on the upper surface of the sapphire substrate, the thickness of the sapphire substrate is 800 μm, and the thickness of the first SiO2 bonding layer is 3 μm;

[0082] S102, evaporating a second SiO2 bonding layer on the lower surface of the GaAs substrate, the thickness of the GaAs substrate is 100 μm, and the thickness of the second SiO2 bonding layer is 3 μm;

[0083] S103, grinding and polishing the first SiO2 bonding layer and the second SiO2 bonding layer; the thickness of the first SiO2 bonding layer after grinding and polishing is 2.5 μm, and the thickness of the second SiO2 bonding layer after grinding and polishing is 2.5 μm;

[0084] S104, aligning the first SiO2 bonding layer and the second SiO2 bonding layer after grinding and polishing, and performing hot pressing bonding to form a SiO2 bonding layer. Specifically, the bonding temperature of the hot pressing bonding is 400° C., and the bonding pressure is 0.25 MPa.

[0085] S200, sequentially growing an N-type semiconductor layer, an active layer and a P-type semiconductor layer on the composite substrate to obtain an AlGaInPAs-based light-emitting diode epitaxial wafer;

[0086] S300, at least removing the composite substrate of the AlGaInPAs-based light-emitting diode epitaxial wafer, depositing an N electrode and a P electrode on the N-type semiconductor layer and the P-type semiconductor layer respectively, to obtain an AlGaInPAs-based light-emitting diode.

[0087] Example 2

[0088] This embodiment provides a method for preparing an AlGaInPAs-based light-emitting diode, which differs from the first embodiment in that the thickness of the sapphire substrate is 400 μm, and the thickness of the GaAs substrate is 300 μm. The rest is the same as the first embodiment.

[0089] Example 3

[0090] This embodiment provides a method for preparing an AlGaInPAs-based light-emitting diode, which differs from Embodiment 2 in that a through hole penetrating the upper and lower surfaces of the sapphire substrate is provided on the sapphire substrate. The rest is the same as Embodiment 2.

[0091] Comparative Example 1

[0092] This comparative example provides a method for preparing an AlGaInPAs-based light-emitting diode, which differs from Example 1 in that the substrate is a GaAs substrate with a thickness of 360 μm. The rest is the same as Example 1.

[0093] Performance Test:

[0094] The AlGaInPAs-based light-emitting diodes prepared in Examples 1 to 3 and Comparative Example 1 were tested for photoelectric performance at a current of 20 mA, and the light efficiency improvement of Examples 1 to 3 relative to Comparative Example 1 was calculated, and the results are shown in Table 1.

[0095] Lighting effect improvement Example 1 2.4％ Example 2 2.8％ Example 3 3.2％

[0096] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A method for preparing an AlGaInPAs-based light-emitting diode, characterized in that: The following steps are involved: providing a composite substrate; An N-type semiconductor layer, an active layer and a P-type semiconductor layer are sequentially grown on the composite substrate to obtain an AlGaInPAs-based light-emitting diode epitaxial wafer; At least the composite substrate of the AlGaInPAs-based light-emitting diode epitaxial wafer is removed, and an N electrode and a P electrode are deposited on the N-type semiconductor layer and the P-type semiconductor layer respectively to obtain an AlGaInPAs-based light-emitting diode; The materials of the N-type semiconductor layer, the active layer and the P-type semiconductor layer are Al x Ga y In (1-x-y) P Z As (1-z) , 0≤x≤1, 0≤y≤1, 0≤x+y≤1, 0≤z≤1; The composite substrate is formed by bonding a sapphire substrate and a GaAs substrate.

2. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 1, characterized in that: The thickness of the sapphire substrate is 200 μm to 2000 μm, and the thickness of the GaAs substrate is 50 μm to 350 μm.

3. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 2, characterized in that: The thickness of the sapphire substrate is 200 μm to 600 μm, and the thickness of the GaAs substrate is 150 μm to 350 μm.

4. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 1, characterized in that: The sapphire substrate and the GaAs substrate are bonded via a SiO2 bonding layer, and the thickness of the SiO2 bonding layer is 1 μm to 10 μm.

5. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 1, characterized in that: The sapphire substrate is provided with through holes penetrating the upper and lower surfaces of the sapphire substrate.

6. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 4, characterized in that: The sapphire substrate and the GaAs substrate are bonded by the following steps: Preparing a first SiO2 bonding layer on the upper surface of the sapphire substrate, with a thickness of 1 μm to 4 μm; Preparing a second SiO2 bonding layer on the lower surface of the GaAs substrate, with a thickness of 1 μm to 4 μm; Grinding and polishing the first SiO2 bonding layer and the second SiO2 bonding layer; The first SiO2 bonding layer and the second SiO2 bonding layer after grinding and polishing are aligned, and the SiO2 bonding layer is formed after hot pressing and bonding.

7. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 6, characterized in that: The bonding temperature of the thermal compression bonding is 300° C. to 500° C., and the bonding pressure is 0.1 MPa to 0.4 MPa.

8. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 1, characterized in that: The N-type semiconductor layer is prepared by the following steps: an N-type buffer layer, an N-type cutoff layer, an N-type contact layer, an N-type extension layer, an N-type electron layer and an N-type electron blocking layer are sequentially grown on the composite substrate; The P-type semiconductor layer is prepared by adopting the following steps: a P-type hole blocking layer, a P-type hole layer, a P-type transition layer, a P-type window layer and a P-type contact layer are grown in sequence on the active layer.

9. The method for preparing an AlGaInPAs-based light-emitting diode according to claim 8, characterized in that: The composite substrate, the N-type buffer layer and the N-type cut-off layer of the AlGaInPAs-based light-emitting diode epitaxial wafer are removed.

10. An AlGaInPAs-based light-emitting diode, characterized in that: The method is as described in any one of claims 1 to 9.

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