Light-emitting diode epitaxial wafer based on a silicon-based buffer layer and preparation method thereof

Abstract

The present invention relates to the field of semiconductor technology, and specifically discloses a light-emitting diode epitaxial wafer based on a silicon-based buffer layer and a preparation method thereof, including: providing a silicon substrate; sequentially depositing a buffer layer, an undoped GaN layer, an n-type GaN layer, a light-emitting layer, an electron blocking layer, and a p-type GaN layer on the silicon substrate along the epitaxial direction; the buffer layer includes a SiN layer, an Al x Si 1‑x N transition layer, an AlN layer, and a low-temperature Al y Ga 1‑y N buffer layer / high-temperature Al y Ga 1‑y N buffer layer superlattice structure; the growth atmosphere of the buffer layer is NH3 / N2. The preparation method of the present invention can effectively reduce the lattice mismatch and thermal mismatch between the silicon substrate and GaN, reduce the defect density, improve the crystal quality of GaN, reduce the cracks on the epitaxial wafer, and improve the light-emitting efficiency of the light-emitting diode.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular, to a light-emitting diode epitaxial wafer based on a silicon-based buffer layer and a preparation method thereof. Background Art

[0002] One of the ultimate goals of the development of GaN-based LEDs is to be applied to general lighting. Compared with traditional light sources (incandescent lamps, fluorescent lamps), LED light sources have obvious advantages. The biggest highlight of GaN-based LEDs is energy saving. The luminous efficiency of incandescent lamps is only 10 - 15 lm / W; while the luminous efficiency of fluorescent lamps is only 60 - 80 lm / W; currently, the luminous efficiency of commercially available LED lamps has basically exceeded 100 lm / W, and with the continuous progress of technology, the lighting efficiency of LED lamps is expected to break through 200 lm / W. In the future of resource shortage and the advocacy of energy conservation and environmental protection, LED lighting has a bright future.

[0003] The key difficulty in growing GaN on a silicon substrate by MOCVD growth technology lies in: the lattice mismatch between wurtzite-structured GaN(0001) and diamond-structured silicon(111) substrate reaches 20.4%, and there is a thermal mismatch as high as 56%. Moreover, Ga will react with Si to damage the substrate surface. Therefore, it is very difficult to grow GaN with high crystal quality on a Si substrate. However, the crystal quality of GaN is still an important factor because defects will also affect the luminous efficiency and reliability of GaN-based LEDs to a certain extent, and the thermal mismatch will cause the epitaxial wafer to bend and crack, making it difficult to prepare an epitaxial wafer without cracks on the surface. Summary of the Invention

[0004] The purpose of the present invention is to provide a light-emitting diode epitaxial wafer based on a silicon-based buffer layer and a preparation method thereof for the existing technical status quo. The preparation method of the present invention can effectively reduce the lattice mismatch and thermal mismatch between the silicon substrate and GaN, reduce the defect density, improve the crystal quality of GaN, reduce the cracks of the epitaxial wafer, and improve the luminous efficiency of the light-emitting diode.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A preparation method of a light-emitting diode epitaxial wafer based on a silicon-based buffer layer, comprising:

[0007] Providing a silicon substrate;

[0008] Sequentially depositing a buffer layer, an undoped GaN layer, an n-type GaN layer, a light-emitting layer, an electron blocking layer, and a p-type GaN layer on the silicon substrate along the epitaxial direction;

[0009] The buffer layer includes a SiN layer and an Al x Si 1-xN transition layer, AlN layer and low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure;

[0010] The growth atmosphere of the buffer layer is NH3 / N2.

[0011] Preferably, the preparation steps of the buffer layer are as follows:

[0012] Under the NH3 / N2 growth atmosphere, deposit an SiN layer, an Al x Si 1-x N transition layer and an AlN layer on the silicon substrate in sequence;

[0013] Under the temperature condition of 1000 - 1300 °C, introduce H2 to process the AlN layer;

[0014] Under the NH3 / N2 growth atmosphere, deposit a low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure on the processed AlN layer.

[0015] Preferably, it further includes:

[0016] Under the temperature condition of 900 - 1100 °C, nitridize the silicon substrate.

[0017] Preferably, in the low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure, the Al component content decreases along the epitaxial direction.

[0018] Preferably, in the low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure includes periodically and alternately grown low-temperature Al y Ga 1-y N buffer layer and high-temperature Al y Ga 1-y N buffer layer, the period is 1 - 10, and in each period, the thickness of the low-temperature Al y Ga 1-y N buffer layer is 0.5 - 5 nm, and the thickness of the high-temperature Al y Ga 1-y N buffer layer is 1 - 10 nm; the low-temperature Al yGa 1-y The growth temperature of the AlGaN buffer layer is 750 - 900 °C, and the growth temperature of the high-temperature AlGaN buffer layer is y Ga 1-y 1000 - 1150 °C.

[0019] Preferably, in the AlSiN transition layer, the Al component content increases along the epitaxial direction, and the Si component content decreases along the epitaxial direction. x Si 1-x N transition layer, the Al component content increases from 0.01 - 0.1 to 0.5 - 0.8 along the epitaxial direction, and the Si component content decreases from 0.8 - 0.9 to 0.2 - 0.5 along the epitaxial direction;

[0020] Preferably, in the AlSiN transition layer, the Al component content increases from 0.01 - 0.1 to 0.5 - 0.8 along the epitaxial direction, and the Si component content decreases from 0.8 - 0.9 to 0.2 - 0.5 along the epitaxial direction; x Si 1-x N transition layer, the Al component content increases from 0.01 - 0.1 to 0.5 - 0.8 along the epitaxial direction, and the Si component content decreases from 0.8 - 0.9 to 0.2 - 0.5 along the epitaxial direction;

[0021] In the low-temperature AlGaN buffer layer / high-temperature AlGaN buffer layer superlattice structure, the Al component content decreases from 0.5 - 0.7 to 0.01 - 0.1 along the epitaxial direction. y Ga 1-y N buffer layer / high-temperature AlGaN buffer layer superlattice structure, the Al component content decreases from 0.5 - 0.7 to 0.01 - 0.1 along the epitaxial direction. y Ga 1-y N buffer layer / high-temperature AlGaN buffer layer superlattice structure, the Al component content decreases from 0.5 - 0.7 to 0.01 - 0.1 along the epitaxial direction.

[0022] Preferably, the thickness of the SiN layer is 0.5 - 5 nm, the thickness of the AlSiN transition layer is 1 - 10 nm, and the thickness of the AlN layer is 5 - 20 nm. x Si 1-x N transition layer is 1 - 10 nm, and the thickness of the AlN layer is 5 - 20 nm.

[0023] Preferably, the electron blocking layer is an AlInGaN layer, wherein the Al component content is 0.005 - 0.1, and the Al component content increases along the epitaxial direction, and the In component content is 0.01 - 0.2.

[0024] A light-emitting diode epitaxial wafer based on a silicon-based buffer layer is prepared according to the preparation method of the light-emitting diode epitaxial wafer based on a silicon-based buffer layer described above.

[0025] The beneficial effects of the present invention are as follows:

[0026] The present invention grows a buffer layer on a silicon substrate in an NH3 / N2 growth atmosphere, and the buffer layer is composed of a sequentially deposited SiN layer, an AlSiN transition layer, an AlN layer, and a low-temperature AlGaN buffer layer / high-temperature AlGaN buffer layer superlattice structure. x Si 1-x N transition layer, an AlN layer, and a low-temperature AlGaN buffer layer / high-temperature AlGaN buffer layer superlattice structure. y Ga 1-y N buffer layer / high-temperature AlGaN buffer layer superlattice structure. y Ga 1-yComposed of an N-buffer layer superlattice structure, it effectively blocks the diffusion of Si atoms on the silicon substrate, reduces the lattice mismatch and thermal mismatch between the silicon substrate and the subsequent GaN material layer, lowers the defect density, improves the crystal quality, reduces the cracks in the epitaxial wafer, and enhances the luminous efficiency of the light-emitting diode. Brief Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of a light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to the present invention.

[0028] Figure 2 It is a flowchart of a method for manufacturing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to the present invention.

[0029] Figure 3 It is a flowchart of a method for manufacturing a buffer layer according to the present invention. Detailed Description of the Invention

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below.

[0031] Please refer to Figure 1 and Figure 2 As shown, the present invention discloses a method for manufacturing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer, including:

[0032] Provide a silicon substrate 1;

[0033] Deposit a buffer layer 2, an undoped GaN layer 3, an n-type GaN layer 4, a light-emitting layer 5, an electron blocking layer 6, and a p-type GaN layer 7 on the silicon substrate 1 in the epitaxial direction in sequence;

[0034] The buffer layer 2 includes a SiN layer 21, an Al x Si 1-x N transition layer 22, an AlN layer 23, and a low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24 deposited in sequence along the epitaxial direction;

[0035] The growth atmosphere of the buffer layer 2 is NH3 / N2.

[0036] Since it is difficult to form a flat surface when the AlN layer 23 is directly deposited on the silicon substrate 1, in the present invention, a SiN layer 21 and an Al x Si 1-x N transition layer 22 are provided between the silicon substrate 1 and the AlN layer 23. By the Al x Si 1-x N transition layer 22, the lattice mismatch between the SiN layer 21 and the AlN layer 23 is reduced. Through the SiN layer 21 and the Alx Si 1-x The setting of the SiN transition layer 22 promotes the two-dimensional growth of the AlN layer 23, which is beneficial to the formation of a dense and flat AlN layer 23, effectively blocks the diffusion of Si atoms on the silicon substrate 1, avoids the problem of the crystal quality degradation of the epitaxial layer caused by the diffusion of Si atoms on the silicon substrate 1, and provides a good growth platform for the growth of the subsequent epitaxial layer. The low-temperature AlyGa1-yN buffer layer 2 / high-temperature AlyGa1-yN buffer layer 2 superlattice structure 24 can further alleviate the lattice mismatch between the AlN layer 23 and the GaN material layer. Among them, the low-temperature Al y Ga 1-y N buffer layer 2 is beneficial to stress release and dislocation reduction. The high-temperature Al y Ga 1-y N buffer layer 2 can improve the atomic mobility and increase the lateral epitaxial growth ability of the high-temperature Al y Ga 1-y N buffer layer 2, improve the crystal quality, and provide a two-dimensional plane with high crystal quality for the subsequently deposited epitaxial layer. The growth atmosphere of the buffer layer 2 is NH3 / N2. On the one hand, it avoids the formation of Si-H impurities by Si and H, which is beneficial to the formation of a high-quality SiN layer 21. On the other hand, it avoids the decrease in the Al incorporation efficiency caused by the parasitic reaction of Al and H2, and further improves the crystal quality of the Al x Si 1-x N transition layer 22 and the AlN layer 23.

[0037] In the present invention, the buffer layer 2 is grown on the silicon substrate 1 in an NH3 / N2 growth atmosphere, and the buffer layer 2 is composed of a sequentially deposited SiN layer 21, an Al x Si 1-x N transition layer 22, an AlN layer 23, and a low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24, effectively blocks the diffusion of Si atoms on the silicon substrate 1, reduces the lattice mismatch and thermal mismatch between the silicon substrate 1 and the subsequent GaN material layer, reduces the defect density, improves the crystal quality, reduces the cracks in the epitaxial wafer, and improves the light emission efficiency of the light-emitting diode.

[0038] In the present invention, the buffer layer 2 is prepared by using a medium-sized A7 MOCVD (Metal-organic Chemical Vapor Deposition, abbreviated as MOCVD) equipment. MOCVD can flexibly change the type or ratio of reactants through the rapid dead-zone-free switching of the gas source, is easy to control the composition and doping amount of the compound, and is more suitable for the preparation of the epitaxial wafer of the present invention.

[0039] Among them, the preparation steps of the buffer layer 2 are as follows:

[0040] In an NH3 / N2 growth atmosphere, a SiN layer 21 and an Al x Si 1-x N transition layer 22 and an AlN layer 23 are sequentially deposited on the silicon substrate 1;

[0041] Under the temperature condition of 1000 - 1300 °C, H2 is introduced to treat the AlN layer 23;

[0042] In an NH3 / N2 growth atmosphere, a low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24 is deposited on the treated AlN layer 23.

[0043] By means of high-temperature H2 treatment, the AlN layer 23 is recrystallized, which can effectively improve the crystal quality of the AlN layer 23 and provide a good growth platform for the subsequent low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24.

[0044] Among them, it also includes:

[0045] Under the temperature condition of 900 - 1100 °C, the silicon substrate 1 is nitrided. After the silicon substrate 1 is nitrided by high-temperature NH3, Si-N bonds are formed on the surface of the silicon substrate 1, improving the ability to form N-Si bonds on the substrate and preparing for the subsequent deposition of the AlN layer. In addition, the nitriding treatment can reduce the deep defect density, avoid the formation of an oxide layer, be beneficial to improving the crystal quality of the epitaxial layer, and improving the luminous efficiency of the light-emitting diode.

[0046] Among them, in the low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24, the Al component content decreases along the epitaxial direction, thereby increasing the lattice matching between the low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24 and the GaN material layer, effectively reducing the dislocation density and crack density, and further improving the crystal quality of the subsequent epitaxial layer.

[0047] Among them, in the low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Aly Ga 1-y The AlGaN buffer layer 2 superlattice structure 24 includes a low-temperature AlGaN buffer layer 2 and a high-temperature AlGaN buffer layer 2 that are periodically and alternately grown in sequence. y Ga 1-y N buffer layer 2 and high-temperature Al y Ga 1-y N buffer layer 2, with a period of 1 to 10. Exemplarily, the period is 1, 3, 6, 8, or 10, but not limited thereto. Preferably, the period is 2 to 10. By alternately stacking multiple periods between the high-AlGaN buffer layer 2 and the low-AlGaN buffer layer 2, thermal stress is fully released, dislocation defects caused by thermal stress are reduced, and the lattice quality of the subsequent epitaxial layer is improved. In each period, the thickness of the low-temperature AlGaN buffer layer 2 is 0.5 to 5 nm, and the thickness of the high-temperature AlGaN buffer layer 2 is 1 to 10 nm. y Ga 1-y N buffer layer 2 and low-Al y Ga 1- y N buffer layer 2, completely releasing thermal stress, reducing dislocation defects caused by thermal stress, and improving the lattice quality of the subsequent epitaxial layer; in each period, the thickness of the low-temperature AlGaN buffer layer 2 is 0.5 to 5 nm, and the thickness of the high-temperature AlGaN buffer layer 2 is 1 to 10 nm. Exemplarily, the thickness of the low-temperature AlGaN buffer layer 2 is 0.5 nm, 1 nm, 2 nm, 2.5 nm, 3 nm, 4 nm, or 5 nm, but not limited thereto. If the thickness of the low-temperature AlGaN buffer layer 2 is too thin, the stress release effect is insufficient; if the thickness is too thick, the defect density is likely to increase. The thickness of the high-temperature AlGaN buffer layer 2 is 1 nm, 3 nm, 5 nm, 7 nm, 9 nm, or 10 nm, but not limited thereto. If the thickness of the high-temperature AlGaN buffer layer 2 is too thin, it is not conducive to forming a flat material layer, and the density of defects increases. y Ga 1-y N buffer layer 2, and the thickness of the high-temperature AlGaN buffer layer 2 is 1 to 10 nm. y Ga 1-y N buffer layer 2. Exemplarily, the thickness of the low-temperature AlGaN buffer layer 2 is 0.5 nm, 1 nm, 2 nm, 2.5 nm, 3 nm, 4 nm, or 5 nm, but not limited thereto. y Ga 1-y N buffer layer 2. If the thickness of the low-temperature AlGaN buffer layer 2 is too thin, the stress release effect is insufficient; if the thickness is too thick, the defect density is likely to increase. y Ga 1-y N buffer layer 2. If the thickness of the high-temperature AlGaN buffer layer 2 is too thin, it is not conducive to forming a flat material layer, and the density of defects increases. y Ga 1-y N buffer layer 2. Exemplarily, the thickness of the high-temperature AlGaN buffer layer 2 is 1 nm, 3 nm, 5 nm, 7 nm, 9 nm, or 10 nm, but not limited thereto. y Ga 1-y N buffer layer 2. If the thickness of the high-temperature AlGaN buffer layer 2 is too thin, it is not conducive to forming a flat material layer, and the density of defects increases. y Ga 1-y The growth temperature of the low-temperature AlGaN buffer layer 2 is 750 to 900 °C. y Ga 1-y N buffer layer 2. If the growth temperature of the low-temperature AlGaN buffer layer 2 is too low, the defect density is likely to increase; if the growth temperature is too high, the stress release effect is poor. y Ga 1-y The growth temperature of the high-temperature AlGaN buffer layer 2 is 1000 to 1150 °C. y Ga 1-y N buffer layer 2. If the growth temperature of the high-temperature AlGaN buffer layer 2 is too low, the lateral growth ability is insufficient, and it is difficult to form a two-dimensional plane.

[0048] Among them, Al x Si 1-xIn the AlSiN transition layer 22, the content of the Al component increases along the epitaxial direction, and the content of the Si component decreases along the epitaxial direction. By the gradual change of the content of the Al component and the Si component, the lattice mismatch between the SiN layer 21 and the AlN layer 23 can be effectively reduced, and the crystal quality of the AlN buffer layer 2 can be improved.

[0049] Among them, Al x Si 1-x In the AlSiN transition layer 22, 0 < x < 1. Preferably, Al x Si 1-x In the AlSiN transition layer 22, the content of the Al component increases from 0.01 - 0.1 to 0.5 - 0.8 along the epitaxial direction, and the content of the Si component decreases from 0.8 - 0.9 to 0.2 - 0.5 along the epitaxial direction; more preferably, the content of the Al component increases from 0.1 to 0.6 along the epitaxial direction, and the content of the Si component decreases from 0.9 to 0.3 along the epitaxial direction.

[0050] Among them, the low - temperature Al y Ga 1-y N buffer layer 2 / high - temperature Al y Ga 1-y In the superlattice structure 24 of the low - temperature AlGaN buffer layer 2 / high - temperature AlGaN buffer layer 2, 0 < y < 1. Preferably, the low - temperature Al y Ga 1-y N buffer layer 2 / high - temperature Al y Ga 1-y In the superlattice structure 24 of the low - temperature AlGaN buffer layer 2 / high - temperature AlGaN buffer layer 2, the content of the Al component decreases from 0.5 - 0.7 to 0.01 - 0.1 along the epitaxial direction. More preferably, the content of the Al component decreases from 0.5 to 0.1 along the epitaxial direction.

[0051] Among them, the thickness of the SiN layer 21 is 0.5 - 5 nm, Al x Si 1-x The thickness of the AlSiN transition layer 22 is 1 - 10 nm, and the thickness of the AlN layer 23 is 5 - 20 nm. Exemplarily, the thickness of the SiN layer 21 is 0.5 nm, 1.5 nm, 2.5 nm, 3.5 nm or 4.5 nm, but not limited thereto. Al x Si 1-x The thickness of the AlSiN transition layer 22 is 1 nm, 2 nm, 4 nm, 6 nm, 8 nm, 9 nm or 10 nm, but not limited thereto. The thickness of the AlN layer 23 is 5 nm, 8 nm, 12 nm, 15 nm, 17 nm, 18 nm or 20 nm, but not limited thereto. If the thickness of the buffer layer 2 is too thick, light absorption will occur, reducing the light - emitting efficiency of the light - emitting diode. If the thickness of the buffer layer 2 is too thin, stress relaxation is incomplete, the defect density increases, affecting the crystal quality of the subsequent epitaxial layer and also reducing the light - emitting efficiency of the light - emitting diode.

[0052] Preferably, the growth pressure of the buffer layer 2 is 50 - 300 torr. A low pressure is beneficial to improving the atomic mobility, increasing the atomic lateral diffusion ability. The buffer layer 2 is more likely to form a two-dimensional plane, which is conducive to the growth of high-quality crystals in the subsequent epitaxial layer.

[0053] Among them, the electron blocking layer 6 is an AlInGaN layer, where the Al component content is 0.005 - 0.1, and the Al component content increases along the epitaxial direction. The In component content is 0.01 - 0.2, which can not only effectively limit the electron overflow but also reduce the hole blocking, and improve the hole injection efficiency into the quantum well.

[0054] Among them, the growth temperature of the undoped GaN layer 3 is 1050 °C - 1200 °C, the pressure is 100 - 600 torr, and the thickness is 1 - 5 μm. The undoped GaN layer 3 has a relatively high growth temperature and a low pressure, and the prepared GaN crystal has better quality. At the same time, as the thickness of GaN increases, the compressive stress will be released through stacking faults, the line defects will decrease, the crystal quality will improve, and the reverse leakage current will decrease. However, increasing the thickness of the GaN layer consumes a large amount of Ga source material, so the thickness should not be too thick.

[0055] Among them, the growth temperature of the n-type GaN layer 4 is 1050 °C - 1200 °C, the pressure is 100 - 600 torr, the thickness is 2 - 3 μm, and the Si doping concentration is 1×10 19 / cm3 - 5×10 19 / cm3. If the thickness is insufficient, it is difficult to effectively release the pressure. A higher Si doping can effectively reduce the resistivity of the n-type GaN layer 4. However, if the Si doping concentration is too high, the crystal quality will be reduced.

[0056] Among them, the light-emitting layer 5 is a periodically alternating stack of InGaN quantum well layers and AlGaN quantum barrier layers, with a period of 6 - 12. The growth temperature of the InGaN quantum well layer is 790 - 810 °C, the thickness is 2 - 5 nm, the growth pressure is 50 - 300 torr, the growth temperature of the AlGaN quantum barrier layer is 800 - 900 °C, the thickness is 5 - 15 nm, and the growth pressure is 50 - 300 torr. The Al component content is 0.01 - 0.1. The light-emitting layer 5 is the region where electrons and holes recombine. A reasonable structure design can significantly increase the overlap degree of the electron and hole wave functions, thereby improving the light-emitting efficiency of the LED device.

[0057] A light-emitting diode epitaxial wafer based on a silicon-based buffer layer is prepared according to the preparation method of the above-mentioned light-emitting diode epitaxial wafer based on a silicon-based buffer layer.

[0058] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0059] Example 1

[0060] Please refer to Figure 1 and Figure 2 As shown, a method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer includes:

[0061] S100. Provide a silicon substrate 1, and perform nitridation treatment on the silicon substrate 1 at a temperature of 1100 °C.

[0062] S200. Deposit a buffer layer 2, an undoped GaN layer 3, an n-type GaN layer 4, a light-emitting layer 5, an electron blocking layer 6, and a p-type GaN layer 7 on the silicon substrate 1 in sequence along the epitaxial direction. The specific steps are as follows:

[0063] S210. Deposit a buffer layer 2 on the silicon substrate 1. Among them, the buffer layer 2 includes a SiN layer 21, an Al x Si 1-x N transition layer 22, an AlN layer 23, and a low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24; refer to Figure 3 As shown, the preparation steps of the buffer layer 2 are as follows:

[0064] S211. Deposit a SiN layer 21 on the silicon substrate 1 under an NH3 / N2 growth atmosphere. The thickness of the SiN layer 21 is 2.5 nm, the growth pressure is 100 torr, and the growth temperature is 850 °C.

[0065] S212. Deposit an Al x Si 1-x N transition layer 22 on the SiN layer 21. The thickness of the Al x Si 1-x N transition layer 22 is 5.5 nm, the growth pressure is 150 torr, the growth temperature is 850 °C, and the Al component content increases from 0.1 to 0.6 along the epitaxial direction, and the Si component content decreases from 0.9 to 0.4 along the epitaxial direction.

[0066] S213. Deposit an AlN layer 23 on the Al x Si 1-x N transition layer 22. The thickness of the AlN layer 23 is 10 nm, the growth pressure is 100 torr, and the growth temperature is 850 °C.

[0067] S214. Under a temperature condition of 1200 °C, introduce H2 to treat the AlN layer 23.

[0068] S215. Deposit a low-temperature Al y Ga 1-y N buffer layer 2 / high-temperature Al y Ga 1-y N buffer layer 2 superlattice structure 24, where the Al component content decreases from 0.5 to 0.1 along the epitaxial direction, the period is 5, and in each period, the thickness of the low-temperature Al y Ga 1-y N buffer layer 2 is 1.5 nm, and the thickness of the high-temperature Al y Ga 1-y N buffer layer 2 is 6.5 nm; the growth temperature of the low-temperature Al y Ga 1-y N buffer layer 2 is 820 °C, and the growth temperature of the high-temperature Al y Ga 1-y N buffer layer 2 is 1050 °C.

[0069] S220. Deposit an undoped GaN layer 3 on the buffer layer 2:

[0070] Among them, the growth temperature of the undoped GaN layer 3 is 1100 °C, the pressure is 150 torr, and the thickness is 3 μm.

[0071] S230. Deposit an n-type GaN layer 4 on the undoped GaN layer 3:

[0072] Among them, the growth temperature of the n-type GaN layer 4 is 1120 °C, the pressure is 100 torr, the thickness is 2 μm, and the Si doping concentration is 2.5×10 19 / cm3.

[0073] S240. Deposit a light-emitting layer 5 on the n-type GaN layer 4;

[0074] Among them, the light-emitting layer 5 is a periodically alternating stack of InGaN quantum well layers and AlGaN quantum barrier layers, the period is 10, the growth temperature of the InGaN quantum well layer is 795 °C, the thickness is 3.5 nm, the growth pressure is 200 torr, the In component content is 0.22, the growth temperature of the AlGaN quantum barrier layer is 855 °C, the thickness is 9.8 nm, the growth pressure is 200 torr, and the Al component content is 0.05.

[0075] S250. Deposit an electron blocking layer 6 on the light-emitting layer 5:

[0076] The electron blocking layer 6 is an AlInGaN layer, among which, the Al component content increases from 0.01 to 0.05 along the epitaxial direction, the In component content is 0.01, the growth pressure is 200 torr, and the growth temperature is 965 °C.

[0077] Deposit a p-type GaN layer 7 on the electron blocking layer 6:

[0078] The growth temperature of the p-type GaN layer 7 is 985 °C, the thickness is 15 nm, the growth pressure is 200 torr, and the Mg doping concentration is 2×10 20 / cm3.

[0079] Example 2

[0080] A method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer, comprising:

[0081] S100. Provide a silicon substrate and perform nitridation treatment on the silicon substrate at a temperature of 1100 °C.

[0082] S200. Deposit a buffer layer, an undoped GaN layer, an n-type GaN layer, a light-emitting layer, an electron blocking layer, and a p-type GaN layer on the silicon substrate in the epitaxial direction in sequence. The specific steps are as follows:

[0083] S210. Deposit a buffer layer on the silicon substrate. The buffer layer includes a SiN layer, an Al x Si 1-x N transition layer, an AlN layer, and a low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure; the preparation steps of the buffer layer are as follows:

[0084] S211. Deposit a SiN layer on the silicon substrate under an NH3 / N2 growth atmosphere. The thickness of the SiN layer is 0.5 nm, the growth pressure is 100 torr, and the growth temperature is 850 °C.

[0085] S212. Deposit an Al x Si 1-x N transition layer on the SiN layer under an NH3 / N2 growth atmosphere. The thickness of the Al x Si 1-x N transition layer is 3 nm, the growth pressure is 150 torr, the growth temperature is 850 °C, and the Al component content increases from 0.1 to 0.6 along the epitaxial direction, and the Si component content decreases from 0.9 to 0.4 along the epitaxial direction.

[0086] S213. Deposit an AlN layer on the Al x Si 1-x N transition layer under an NH3 / N2 growth atmosphere. The thickness of the AlN layer is 5 nm, the growth pressure is 100 torr, and the growth temperature is 850 °C.

[0087] S214. At a temperature of 1200 °C, introduce H2 to treat the AlN layer.

[0088] S215. Under an NH3 / N2 growth atmosphere, deposit a low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure, where the Al component content decreases from 0.5 to 0.1 along the epitaxial direction, the period is 5, and in each period, the low-temperature Al y Ga 1-y N buffer layer has a thickness of 3 nm, and the high-temperature Al y Ga 1-y N buffer layer has a thickness of 10 nm; the low-temperature Al y Ga 1-y N buffer layer has a growth temperature of 820 °C, and the high-temperature Al y Ga 1-y N buffer layer has a growth temperature of 1050 °C.

[0089] S220. Deposit an undoped GaN layer on the buffer layer:

[0090] Among them, the undoped GaN layer has a growth temperature of 1100 °C, a pressure of 150 torr, and a thickness of 3 μm.

[0091] S230. Deposit an n-type GaN layer on the undoped GaN layer:

[0092] Among them, the n-type GaN layer has a growth temperature of 1120 °C, a pressure of 100 torr, a thickness of 2 μm, and an Si doping concentration of 2.5×10 19 / cm3.

[0093] S240. Deposit a light-emitting layer on the n-type GaN layer;

[0094] Among them, the light-emitting layer is a periodically alternating stack of InGaN quantum well layers and AlGaN quantum barrier layers, the period is 10, the InGaN quantum well layer has a growth temperature of 795 °C, a thickness of 3.5 nm, a growth pressure of 200 torr, an In component content of 0.22, the AlGaN quantum barrier layer has a growth temperature of 855 °C, a thickness of 9.8 nm, a growth pressure of 200 torr, and an Al component content of 0.05.

[0095] S250. Deposit an electron blocking layer on the light-emitting layer:

[0096] The electron blocking layer is an AlInGaN layer, wherein the Al component content increases from 0.01 to 0.05 along the epitaxial direction, the In component content is 0.01, the growth pressure is 200 torr, and the growth temperature is 965 °C.

[0097] S250. Deposit a p-type GaN layer on the electron blocking layer:

[0098] The growth temperature of the p-type GaN layer is 985 °C, the thickness is 15 nm, the growth pressure is 200 torr, and the Mg doping concentration is 2×10 20 / cm3.

[0099] Example 3

[0100] A method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer, comprising:

[0101] S100. Provide a silicon substrate and perform nitridation treatment on the silicon substrate at a temperature of 1100 °C;

[0102] S200. Sequentially deposit a buffer layer, an undoped GaN layer, an n-type GaN layer, a light-emitting layer, an electron blocking layer, and a p-type GaN layer on the silicon substrate along the epitaxial direction. The specific steps are as follows:

[0103] S210. Deposit a buffer layer on the silicon substrate. The buffer layer includes a SiN layer, an Al x Si 1-x N transition layer, an AlN layer, and a low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure; the preparation steps of the buffer layer are as follows:

[0104] S211. Deposit a SiN layer on the silicon substrate in an NH3 / N2 growth atmosphere. The thickness of the SiN layer is 2.5 nm, the growth pressure is 100 torr, and the growth temperature is 850 °C.

[0105] S212. Deposit an Al x Si 1-x N transition layer on the SiN layer in an NH3 / N2 growth atmosphere. The thickness of the Al x Si 1-x N transition layer is 5.5 nm, the growth pressure is 150 torr, the growth temperature is 850 °C, the Al component content increases from 0.2 to 0.8 along the epitaxial direction, and the Si component content decreases from 0.8 to 0.2 along the epitaxial direction.

[0106] S213. In an NH3 / N2 growth atmosphere, deposit on the Al x Si1-x An AlN layer is deposited on the N transition layer. The thickness of the AlN layer is 10 nm, the growth pressure is 100 torr, and the growth temperature is 850 °C.

[0107] S214. At a temperature of 1200 °C, H2 is introduced to treat the AlN layer.

[0108] S215. Under an NH3 / N2 growth atmosphere, a low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure is deposited on the treated AlN layer. The Al component content decreases from 0.7 to 0.1 along the epitaxial direction, the period is 5, and the thickness of the low-temperature Al y Ga 1-y N buffer layer is 1.5 nm, and the thickness of the high-temperature Al y Ga 1-y N buffer layer is 6.5 nm; the growth temperature of the low-temperature Al y Ga 1-y N buffer layer is 820 °C, and the growth temperature of the high-temperature Al y Ga 1-y N buffer layer is 1050 °C.

[0109] S220. An undoped GaN layer is deposited on the buffer layer:

[0110] Among them, the growth temperature of the undoped GaN layer is 1100 °C, the pressure is 150 torr, and the thickness is 3 μm.

[0111] S230. An n-type GaN layer is deposited on the undoped GaN layer:

[0112] Among them, the growth temperature of the n-type GaN layer is 1120 °C, the pressure is 100 torr, the thickness is 2 μm, and the Si doping concentration is 2.5×10 19 / cm3.

[0113] S240. A light-emitting layer is deposited on the n-type GaN layer;

[0114] Among them, the light-emitting layer is a periodically alternating stack of InGaN quantum well layers and AlGaN quantum barrier layers, the period is 10, the growth temperature of the InGaN quantum well layer is 795 °C, the thickness is 3.5 nm, the growth pressure is 200 torr, the In component content is 0.22, the growth temperature of the AlGaN quantum barrier layer is 855 °C, the thickness is 9.8 nm, the growth pressure is 200 torr, and the Al component content is 0.05.

[0115] S250. An electron blocking layer is deposited on the light-emitting layer:

[0116] The electron blocking layer is an AlInGaN layer, wherein the Al component content increases from 0.01 to 0.05 along the epitaxial direction, the In component content is 0.01, the growth pressure is 200 torr, and the growth temperature is 965 °C.

[0117] S250. Deposit a p-type GaN layer on the electron blocking layer:

[0118] The growth temperature of the p-type GaN layer is 985 °C, the thickness is 15 nm, the growth pressure is 200 torr, and the Mg doping concentration is 2×10 20 / cm3.

[0119] Comparative Example 1

[0120] The difference between this comparative example and Example 1 is that step S214 is not performed.

[0121] Comparative Example 2

[0122] The difference between this comparative example and Example 1 is that in steps S211, 212, 213, and 215, the growth atmosphere is H2.

[0123] Comparative Example 3

[0124] The difference between this comparative example and Example 1 is that the buffer layer does not include an Al x Si 1-x N transition layer.

[0125] Comparative Example 4

[0126] The difference between this comparative example and Example 1 is that the buffer layer does not include a low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure.

[0127] Comparative Example 5

[0128] The difference between this comparative example and Example 1 is that step S215 is as follows:

[0129] Under an NH3 / N2 growth atmosphere, deposit an Al y Ga 1-y N buffer layer on the treated AlN layer, wherein the Al component content remains at 0.5 along the epitaxial direction, the period is 5, and the thickness of the Al y Ga 1-y N buffer layer in each period is 1.5 nm; the growth temperature of the Al y Ga 1-y N buffer layer is 820 °C.

[0130] Comparative Example 6

[0131] The difference between this comparative example and Example 1 is as follows: In step S210, a buffer layer is deposited on the silicon substrate. The buffer layer is an AlN layer. Specifically, the AlN layer is deposited on the silicon substrate under an NH3 / N2 growth atmosphere, and the thickness of the AlN layer is 39.5 nm.

[0132] The luminous efficiency of the epitaxial wafers prepared in Examples 1 to 3 and Comparative Examples 1 to 6 was tested. The luminous efficiencies measured in Examples 1 to 3 and Comparative Examples 1 to 5 were compared with the luminous efficiency measured in Comparative Example 6 to obtain the light efficiency improvement rates of Examples 1 to 3 and Comparative Examples 1 to 5. A positive light efficiency improvement rate indicates that the luminous efficiency of this experimental group is higher than that of Comparative Example 6, and a negative light efficiency improvement rate indicates that the luminous efficiency of this experimental group is lower than that of Comparative Example 6.

[0133] The measured results are as follows:

[0134]

[0135]

[0136] The experimental results show that the results of Examples 1 to 3 are better than those of Comparative Examples 3 to 6. It can be seen that the buffer layer composed of the SiN layer, Al x Si 1-x N transition layer, AlN layer, and low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure has a high luminous efficiency; the light efficiency improvement value of Example 1 is higher than that of Comparative Example 1 and Comparative Example 2. It can be seen that during the preparation of the buffer layer, high-temperature H2 treatment of the AlN layer and the use of an NH3 / N2 growth atmosphere can improve the crystal quality; the light efficiency improvement value of Example 1 is higher than that of Comparative Example 5. It can be seen that the low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure can improve the luminous efficiency of the epitaxial wafer more than the conventional Al y Ga 1-y N buffer layer.

[0137] The above are only the preferred embodiments of the present invention and do not impose any formal restrictions on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications using the technical content prompted above to form equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the present invention's solution.

Claims

1. A method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer, characterized in that, Including: Providing a silicon substrate; Successively depositing a buffer layer, an undoped GaN layer, an n-type GaN layer, a light-emitting layer, an electron blocking layer, and a p-type GaN layer on the silicon substrate along the epitaxial direction; The buffer layer includes an SiN layer, Al x Si 1-x N transition layer, an AlN layer, and a low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure; The growth atmosphere of the buffer layer is NH3 / N2.

2. The preparation method of the light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to claim 1, wherein, The preparation steps of the buffer layer are as follows: Under the NH3 / N2 growth atmosphere, a SiN layer and Al are sequentially deposited on the silicon substrate x Si 1-x N transition layer and AlN layer; Under the temperature condition of 1000-1300 °C, introducing H2 to treat the AlN layer; Deposit a low-temperature Al on the treated AlN layer under an NH3 / N2 growth atmosphere y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y N buffer layer superlattice structure.

3. The method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to claim 2, wherein Further including: Under the temperature condition of 900-1100 °C, nitriding the silicon substrate.

4. The preparation method of the light-emitting diode epitaxial wafer based on the silicon-based buffer layer according to claim 1, characterized in that, The low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y In the N buffer layer / high-temperature AlGaN superlattice structure, the Al component content decreases along the epitaxial direction.

5. The manufacturing method of the light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to claim 4, wherein, The low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y The N buffer layer superlattice structure includes a low-temperature Al y Ga 1-y N buffer layer and a high-temperature Al y Ga 1-y N buffer layer that grow alternately in sequence periodically, with a period of 1 to 10. In each period, the thickness of the low-temperature Al y Ga 1-y N buffer layer is 0.5 to 5 nm, and the thickness of the high-temperature Al y Ga 1-y N buffer layer is 1 to 10 nm; the growth temperature of the low-temperature Al y Ga 1-y N buffer layer is 750 to 900 °C, and the growth temperature of the high-temperature Al y Ga 1-y N buffer layer is 1000 to 1150 °C.

6. The method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to claim 1, wherein, The Al x Si 1-x In the N transition layer, the content of the Al component increases along the epitaxial direction, and the content of the Si component decreases along the epitaxial direction.

7. The preparation method of the light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to claim 1, wherein The Al x Si 1-x In the AlSiN transition layer, the content of the Al component increases from 0.01 to 0.1 and then increases to 0.5 to 0.8 along the epitaxial direction, and the content of the Si component decreases from 0.8 to 0.9 and then decreases to 0.2 to 0.5 along the epitaxial direction; The low-temperature Al y Ga 1-y N buffer layer / high-temperature Al y Ga 1-y In the N buffer layer / high-temperature AlGaN superlattice structure, the Al component content decreases from 0.5 - 0.7 to 0.01 - 0.1 along the epitaxial direction.

8. The method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to claim 1, characterized in that, The thickness of the SiN layer is 0.5 to 5 nm, and the Al x Si 1-x N transition layer has a thickness of 1 to 10 nm, and the AlN layer has a thickness of 5 to 20 nm.

9. The method for preparing a light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to claim 1, wherein The electron blocking layer is an AlInGaN layer, wherein the Al component content is 0.005-0.1, and the Al component content increases along the epitaxial direction, and the In component content is 0.01-0.

2.

10. A light-emitting diode epitaxial wafer based on a silicon-based buffer layer, characterized in that, Prepared by the preparation method of the light-emitting diode epitaxial wafer based on a silicon-based buffer layer according to any one of claims 1 to 9.

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