Light emitting diode epitaxial wafer and preparation method thereof, and light emitting diode
By introducing a composite transition layer structure into GaN-based LED epitaxial wafers, the defect problem caused by lattice mismatch was solved, improving luminous efficiency and antistatic capability, thus achieving efficient LED epitaxial wafer fabrication.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGXI ZHAO CHI SEMICON CO LTD
- Filing Date
- 2023-12-13
- Publication Date
- 2026-06-30
AI Technical Summary
In the epitaxial manufacturing process of GaN-based light-emitting diodes, the defect density increases due to lattice mismatch and thermal mismatch between the heterostructure and GaN material, which affects luminous efficiency and antistatic capability.
A composite transition layer structure is adopted, including periodically stacked InxAl1-xN layers, Mg-doped InN layers, InyGa1-yN layers and GaN layers. By adjusting the growth temperature and doping concentration of each layer, mismatch stress is relieved and lattice quality and surface flatness are improved.
It improves the luminous efficiency and antistatic capability of light-emitting diodes, reduces defect density, and improves the crystal quality of epitaxial wafers.
Smart Images
Figure CN117691015B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor optoelectronic devices, and more particularly to a light-emitting diode epitaxial wafer and its fabrication method, and a light-emitting diode. Background Technology
[0002] GaN materials, due to their high breakdown voltage and low dielectric constant, are widely used in high-voltage power electronic devices, light-emitting diodes (LEDs), and lasers, making them a research hotspot. In the epitaxial fabrication of GaN-based LEDs, considering factors such as cost and technological maturity, heterogeneous substrates such as silicon carbide, silicon, or sapphire are often used for epitaxial growth. However, due to significant lattice and thermal mismatches between the heterogeneous substrate and the GaN material, defect density increases and dislocations are generated. In severe cases, this can even lead to surface roughening and cracking of the epitaxial wafer. Furthermore, the extension of underlying defects into the active region can form multiple non-radiative recombination centers, resulting in a reduction in the luminous efficiency of the LED.
[0003] To address the significant lattice mismatch between the substrate and the GaN epitaxial layer, the industry commonly employs PVD (Physical Vapor Deposition) to deposit an AlN buffer layer on the substrate, followed by the sequential deposition of each epitaxial layer on the buffer layer. However, the PVD-deposited AlN buffer layer is too dense, hindering the three-dimensional growth of the intrinsic GaN layer. Furthermore, the AlN buffer layer experiences significant unreleased stress, leading to coarsening or cracking of the epitaxial wafer. In addition, while the AlN buffer layer can alleviate the lattice mismatch between the substrate and GaN material to some extent, it still generates numerous dislocations and defects. These defects not only affect the crystal quality of the epitaxial layer but also, as they extend upwards, impact the luminous efficiency of the active region and reduce the electrostatic discharge immunity of the LED. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide an epitaxial wafer for a light-emitting diode and a method for preparing the same, which can improve the luminous efficiency of the light-emitting diode and enhance its antistatic capability.
[0005] Another technical problem to be solved by the present invention is to provide a light-emitting diode with high luminous efficiency and high anti-static capability.
[0006] To address the aforementioned problems, this invention discloses a light-emitting diode epitaxial wafer, comprising a substrate and a composite transition layer, an intrinsic GaN layer, a U-type GaN layer, an N-type GaN layer, a stress-relieving layer, a multiple quantum well layer, an electron blocking layer, and a P-type GaN layer sequentially disposed on the substrate. The composite transition layer has a periodic structure with a period number of 1 to 4, and each period includes sequentially stacked In layers. x Al 1-x N-layer, Mg-doped InN-layer, Iny Ga 1-y N-layer and GaN-layer;
[0007] Where x < 0.1, y < 0.2, x < y;
[0008] The In x Al 1-x The growth temperature of the N layer is ≥800℃;
[0009] The Mg doping concentration in the Mg-doped InN layer is <5×10⁻⁶. 17 cm -3 ;
[0010] The thickness of the Mg-doped InN layer is <1 nm;
[0011] The growth temperature of the GaN layer is ≤850℃.
[0012] As an improvement to the above technical solution, x is 0 to 0.05 and y is 0.05 to 0.15.
[0013] As an improvement to the above technical solution, the In x Al 1-x The growth temperature of the N layer is 800℃~850℃.
[0014] As an improvement to the above technical solution, the Mg doping concentration in the Mg-doped InN layer is 1.2 × 10⁻⁶. 17 cm -3 ~3.5×10 17 cm -3 .
[0015] As an improvement to the above technical solution, the thickness of the Mg-doped InN layer is 0.1 nm to 0.5 nm.
[0016] As an improvement to the above technical solution, the growth temperature of the GaN layer is 800℃~850℃.
[0017] As an improvement to the above technical solution, the In x Al 1-x The thickness of the N layer is 10nm to 20nm, and the In y Ga 1-y The thickness of the N layer is 8nm to 15nm, and the thickness of the GaN layer is 10nm to 20nm.
[0018] Accordingly, the present invention also discloses a method for preparing a light-emitting diode epitaxial wafer, which includes:
[0019] A substrate is provided on which a composite transition layer, an intrinsic GaN layer, a U-type GaN layer, an N-type GaN layer, a stress-relieving layer, a multiple quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially grown. The composite transition layer has a periodic structure with 1 to 4 periods, and each period includes sequentially stacked In layers. x Al 1-x N-layer, Mg-doped InN-layer, In y Ga 1-y N-layer and GaN-layer;
[0020] Where x < 0.1, y < 0.2, x < y;
[0021] The In x Al 1-x The growth temperature of the N layer is ≥800℃;
[0022] The Mg doping concentration in the Mg-doped InN layer is <5×10⁻⁶. 17 cm -3 ;
[0023] The thickness of the Mg-doped InN layer is <1 nm;
[0024] The growth temperature of the GaN layer is ≤850℃.
[0025] As an improvement to the above technical solution, the In x Al 1-x The growth pressure of the N layer is 100 torr to 200 torr;
[0026] The growth temperature of the Mg-doped InN layer is 700℃~750℃, and the growth pressure is 100 torr~200 torr.
[0027] The In y Ga 1-y The growth temperature of the N layer is 750℃~800℃, and the growth pressure is 100 torr~200 torr;
[0028] The growth pressure of the GaN layer is 100 to 200 torr.
[0029] Accordingly, the present invention also discloses a light-emitting diode, which includes the above-mentioned light-emitting diode epitaxial wafer.
[0030] Implementing this invention has the following beneficial effects:
[0031] 1. In the epitaxial wafer of the light-emitting diode of the present invention, the composite transition layer has a periodic structure, and each period includes sequentially stacked In layers. x Al 1-x N-layer, Mg-doped InN-layer, In y Ga1-y N-layers and GaN layers; where In x Al 1-x The N-layer acts as a high-temperature buffer layer, alleviating the mismatch stress between the substrate and the GaN material. Its high barrier also prevents substrate defects from extending upwards, reducing defect density, improving lattice quality, and enhancing diode luminous efficiency. The Mg-doped InN layer is relatively thin, forming a near-two-dimensional structure, and the small amount of Mg doping provides more dangling bonds, reducing the In... x Al 1-x N-layer and In y Ga 1-y Mismatch stress between layers N; x < 0.1, y < 0.2, x < y, such that In y Ga 1-y N-layer and In x Al 1-x The stress difference between layers N can partially offset In x Al 1-x The stress between the N-layer and the substrate is initially released, improving the surface flatness of the epitaxial wafer and enhancing its antistatic properties. The GaN layer, grown at a lower temperature, plays a role in defect repair, filling and repairing In layers. x Al 1-x N-layer, Mg-doped InN-layer and In y Ga 1-y Growth defects in the N-layer improve the crystal quality of the composite transition layer and provide a basis for the three-dimensional growth of the intrinsic GaN layer. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the structure of a light-emitting diode epitaxial wafer in one embodiment of the present invention;
[0033] Figure 2 This is a schematic diagram of the composite transition layer in one embodiment of the present invention;
[0034] Figure 3 This is a flowchart of a method for preparing an epitaxial wafer for a light-emitting diode according to an embodiment of the present invention. Detailed Implementation
[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.
[0036] refer to Figures 1-2 The present invention discloses a light-emitting diode epitaxial wafer, comprising a substrate 1 and a composite transition layer 2, an intrinsic GaN layer 3, a U-type GaN layer 4, an N-type GaN layer 5, a stress relief layer 6, a multiple quantum well layer 7, an electron blocking layer 8, and a P-type GaN layer 9 sequentially disposed on the substrate 1.
[0037] Among them, the composite transition layer 2 is a periodic structure with 1 to 4 periods, and each period includes In layers stacked sequentially. x Al 1-x N-layer 21, Mg-doped In; N-layer 22, In y Ga 1-y N-layer 23 and GaN-layer 24.
[0038] Among them, In x Al 1-x The N layer 21 acts as a high-temperature buffer layer, relieving the mismatch stress between the substrate 1 and the GaN material. In addition, the high barrier can prevent the defects in the substrate 1 from extending upward, reducing the defect density, improving the lattice quality, and improving the luminous efficiency of the diode.
[0039] Specifically, x < 0.1, such that In x Al 1-x The lattice mismatch between the N layer 21 and the substrate is small. Exemplarily, x is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, or 0.07, but is not limited thereto. Preferably, x is 0 to 0.05.
[0040] Specifically, In x Al 1-x The growth temperature of layer N21 is ≥800℃, In x Al 1-x The higher growth temperature of layer N21 results in a smoother surface and reduced defects. Exemplary growth temperatures include 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, or 870°C, but are not limited to these. Preferably, In... x Al 1-x The growth temperature of N layer 21 is 800℃~850℃.
[0041] Specifically, In x Al 1-x The thickness of the N layer 21 is 10nm to 25nm, preferably 10nm to 20nm, and exemplary are 12nm, 14nm, 16nm or 18nm, but not limited thereto.
[0042] Among them, the thickness of the Mg-doped InN layer 22 is <1 nm, which is relatively thin, forming a near-two-dimensional structure. Furthermore, the small amount of Mg doping provides more dangling bonds and reduces the In... x Al 1-x N-layer 21 and In y Ga 1-y Mismatch stress between N layers 23. For example, the thickness of the Mg-doped InN layer 22 is 0.1 nm, 0.3 nm, 0.5 nm, or 0.7 nm, but is not limited thereto. Preferably, the thickness of the Mg-doped InN layer 22 is 0.1 nm to 0.5 nm.
[0043] Specifically, the Mg doping concentration in the Mg-doped InN layer 22 is < 5 × 10⁻⁶. 17 cm -3 For example, the doping concentration of Mg is 9 × 10⁻⁶. 16 cm -3 2×10 17 cm -3 3×10 17 cm -3 or 4×10 17 cm -3 However, it is not limited to this. Preferably, the Mg doping concentration is 1.2 × 10⁻⁶. 17 cm -3 ~3.5×10 17 cm -3 .
[0044] Among them, In x Al 1-x In layer N, x < 0.1, In y Ga 1-y In layer N, y < 0.2 and x < y, such that In y Ga 1-y N-layer 21 and In x Al 1-x The stress difference between layers N and 23 can partially offset In x Al 1-x The stress between the N layer 21 and the substrate 1 is initially released, improving the surface flatness of the epitaxial wafer and enhancing its antistatic capability. For example, y is 0.05, 0.08, 0.1, 0.13, 0.15, or 0.17, but is not limited thereto. Preferably, y is 0.05 to 0.15.
[0045] Specifically, In y Ga 1-y The thickness of the N layer 23 is 8nm to 18nm, preferably 8nm to 15nm, and exemplary are 10nm, 12nm, 13nm or 14nm, but not limited thereto.
[0046] Among them, the GaN layer 24, grown at a relatively low temperature, plays a role in defect repair, patching and filling In. x Al 1-x N-layer 21, Mg-doped InN-layer 22 and In y Ga 1-y The growth defects of the N layer 23 improve the crystal quality of the composite transition layer 2, and at the same time provide a basis for the three-dimensional growth of the intrinsic GaN layer 3.
[0047] Specifically, the growth temperature of GaN layer 24 is ≤850℃, and exemplary values are 780℃, 800℃, 820℃ or 840℃, but it is not limited thereto. Preferably, the growth temperature of GaN layer 24 is 800℃~850℃.
[0048] Specifically, the thickness of the GaN layer 24 is 8nm to 22nm, preferably 10nm to 20nm, and exemplary are 12nm, 14nm, 16nm or 18nm, but not limited thereto.
[0049] The substrate 1 can be a sapphire substrate, a silicon substrate, or a SiC substrate, but is not limited to these. A sapphire substrate is preferred.
[0050] The thickness of the intrinsic GaN layer 3 is 2μm to 3.5μm, with exemplary thicknesses of 2.6μm, 2.8μm, 3μm, 3.2μm or 3.4μm, but not limited thereto.
[0051] The dopant element in the U-type GaN layer 4 is unintentional, obtained by diffusion from a small amount in the N-type GaN layer 5. Specifically, the dopant element is Si, but not limited to it, and the doping concentration is 3.5 × 10⁻⁶. 17 cm -3 ~1×10 18 cm -3 The thickness of the U-shaped GaN layer 4 is 0.5 μm to 1 μm, with exemplary thicknesses of 0.6 μm, 0.7 μm, 0.8 μm or 0.9 μm, but not limited thereto.
[0052] The N-type GaN layer 5 is doped with Si, but is not limited to Si. The doping concentration of the N-type GaN layer 5 is 3.5 × 10⁻⁶. 18 cm -3 ~6×10 18 cm -3 The thickness of the N-type GaN layer 5 is 1 μm to 2.5 μm, with exemplary thicknesses of 1.2 μm, 1.4 μm, 1.6 μm or 1.8 μm, but not limited thereto.
[0053] Among them, stress relief layer 6 has a periodic structure with 4 to 9 periods. Each period includes sequentially stacked InGaN layers and Si-doped GaN layers. The In content of the InGaN layers is 0.05 to 0.15%, and the doping concentration of the Si-doped GaN layers is 3.2 × 10⁻⁶. 17 cm -3 ~6.5×10 17 cm -3 The thickness of a single InGaN layer is 4nm to 6nm, and the thickness of a single Si-doped GaN layer is 5nm to 10nm.
[0054] Among them, the multi-quantum-well layer 7 consists of alternating stacked InGaN quantum well layers, GaN capping layers, and Si-doped GaN quantum barrier layers, with a period number of 6–15. The In content of the InGaN quantum well layers is 0.2–0.4%, the thickness of a single InGaN quantum well layer is 2 nm–5 nm, the thickness of a single GaN capping layer is 1 nm–2 nm, and the Si doping concentration in the Si-doped GaN quantum barrier layer is 2.5 × 10⁻⁶. 17 cm -3 ~4.5×10 17 cm -3 The thickness of a single Si-doped GaN quantum barrier layer is 8 nm to 20 nm.
[0055] The electron blocking layer 8 is an AlGaN layer, but is not limited to it. The thickness of the electron blocking layer 8 is 20 nm to 100 nm, and the proportion of Al component is 0.45% to 0.7%.
[0056] The doping element in the p-type GaN layer 9 is Mg, but it is not limited to Mg. The Mg doping concentration in the p-type GaN layer 9 is 5.5 × 10⁻⁶. 18 cm -3 ~7.5×10 19 cm -3 The thickness of the p-type GaN layer 9 is 40nm to 200nm.
[0057] Accordingly, refer to Figure 3 The present invention also discloses a method for preparing a light-emitting diode epitaxial wafer, which includes the following steps:
[0058] S101: Provides a substrate;
[0059] S102: Growing a composite transition layer on the substrate;
[0060] Specifically, in one embodiment of the present invention, In is periodically and sequentially grown in MOCVD. x Al 1-x N-layer, Mg-doped InN-layer, In y Ga 1-y An N-layer and a GaN-layer are used to form a composite transition layer. In... x Al 1-xThe growth temperature of the N-layer is 800℃~850℃, and the growth pressure is 100 torr~200 torr. During growth, NH3 is introduced as the N source, TMI as the In source, and TMAl as the Al source in the MOCVD reaction chamber, with N2 as the carrier gas. The growth temperature of the Mg-doped InN-layer is 700℃~750℃, and the growth pressure is 100 torr~200 torr. During growth, NH3 is introduced as the N source, TMI as the In source, and CP2Mg as the Mg doping source in the MOCVD reaction chamber, with N2 as the carrier gas. In... y Ga 1-y The growth temperature of the N layer is 750℃~800℃, and the growth pressure is 100torr~200torr. During growth, NH3 is introduced as the N source, N2 is used as the carrier gas, TMGa is introduced as the Ga source, and TMIn is introduced as the In source in the MOCVD reaction chamber. The growth temperature of the GaN layer is 800℃~850℃, and the growth pressure is 100torr~200torr. During growth, NH3 is introduced as the N source, N2 is used as the carrier gas, and TMGa is introduced as the Ga source in the MOCVD reaction chamber.
[0061] S103: Intrinsic GaN layer is grown on the composite transition layer;
[0062] Specifically, intrinsic GaN layers were grown in MOCVD at a temperature of 1100℃ to 1150℃ and a pressure of 150 torr to 300 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source; H2 and N2 were used as carrier gases, and TMGa was introduced as the Ga source.
[0063] S104: A U-shaped GaN layer is grown on the intrinsic GaN layer;
[0064] Specifically, U-shaped GaN layers are grown in MOCVD at a temperature of 1100℃ to 1200℃ and a pressure of 150 torr to 260 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source, H2 and N2 are used as carrier gases, and TMGa is introduced as the Ga source.
[0065] S105: An N-type GaN layer is grown on a U-type GaN layer;
[0066] Specifically, an N-type GaN layer is grown in MOCVD at a temperature of 1000℃ to 1100℃ and a pressure of 100 torr to 150 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source, and SiH4 is introduced as the N-type doping source; N2 is used as the carrier gas, and TMGa is introduced as the Ga source.
[0067] S106: A stress-relieving layer is grown on an N-type GaN layer;
[0068] Specifically, InGaN and Si-doped GaN layers are periodically grown in MOCVD to form stress-relieving layers. The InGaN layer is grown at a temperature of 800℃–850℃ and a growth pressure of 100 torr–200 torr. During growth, NH3 is introduced as the N source, N2 as the carrier gas, TEGa as the Ga source, and TMI as the In source in the MOCVD reaction chamber. Similarly, the Si-doped GaN layer is grown at a temperature of 850℃–900℃ and a growth pressure of 100 torr–200 torr. During growth, NH3 is introduced as the N source, SiH4 as the Si source, N2 and H2 as the carrier gases, and TEGa as the Ga source in the MOCVD reaction chamber.
[0069] S107: Growth of a multi-quantum well layer on the stress-relief layer;
[0070] Specifically, an InGaN quantum well layer, a GaN capping layer, and a Si-doped GaN quantum barrier layer are periodically grown in MOCVD to form a multi-quantum well layer. The InGaN quantum well layer is grown at a temperature of 700℃–750℃ and a growth pressure of 100 torr–150 torr. During growth, NH3 is introduced as the N source, N2 as the carrier gas, TEGa as the Ga source, and TMI as the In source in the MOCVD reaction chamber. Similarly, the GaN capping layer is grown at a temperature of 700℃–750℃ and a growth pressure of 100 torr–150 torr. During growth, NH3 is introduced as the N source, H2 and N2 as the carrier gases, and TEGa as the Ga source in the MOCVD reaction chamber. The growth temperature of the Si-doped GaN quantum barrier layer is 850℃~900℃, and the growth pressure is 100 torr~200 torr. During growth, NH3 is introduced as the N source, SiH4 is introduced as the Si source, H2 and N2 are used as carrier gases, and TEGa is introduced as the Ga source in the MOCVD reaction chamber.
[0071] S108: An electron blocking layer is grown on a multi-quantum-well layer;
[0072] Specifically, an AlGaN layer is grown in MOCVD as an electron blocking layer. The growth temperature is 900℃~1000℃, and the growth pressure is 100 torr~150 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source, N2 is used as the carrier gas, TMAl is introduced as the Al source, and TEGa is introduced as the Ga source.
[0073] S109: A P-type GaN layer is grown on an electron blocking layer;
[0074] Specifically, a P-type GaN layer is grown in MOCVD at a temperature of 850℃ to 950℃ and a pressure of 200 torr to 400 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source, and CP2Mg is introduced as the P-type doping source; H2 and N2 are used as carrier gases, and TMGa is introduced as the Ga source.
[0075] The present invention will be further described below with reference to specific embodiments:
[0076] Example 1
[0077] This embodiment provides a light-emitting diode epitaxial wafer, referenced... Figures 1-2 It includes a substrate 1 and a composite transition layer 2, an intrinsic GaN layer 3, a U-type GaN layer 4, an N-type GaN layer 5, a stress relief layer 6, a multiple quantum well layer 7, an electron blocking layer 8, and a P-type GaN layer 9 sequentially disposed on the substrate 1.
[0078] Substrate 1 is a sapphire substrate.
[0079] Among them, the composite transition layer 2 is a periodic structure with 2 periods, and each period includes In layers stacked sequentially. x Al 1-x N-layer 21, Mg-doped In; N-layer 22, In y Ga 1-y N-layer 23 and GaN-layer 24. In x Al 1-x In layer N, 21, x is 0.07, In x Al 1-x The growth temperature of layer N21 is 870℃, In x Al 1-x The thickness of N layer 21 is 25 nm. The thickness of Mg-doped InN layer 22 is 0.7 nm, and the Mg doping concentration is 9 × 10⁻⁶. 16 cm -3 In y Ga 1-y In layer N, y is 0.17, In y Ga 1-y The thickness of the N layer 23 is 18 nm. The GaN layer 24 is grown at a temperature of 780 °C and has a thickness of 22 nm.
[0080] The intrinsic GaN layer 3 has a thickness of 2.7 μm. The U-shaped GaN layer 4 is doped with Si, and its doping concentration is 8 × 10⁻⁶. 17 cm -3 Its thickness is 0.55 μm. The N-type GaN layer 5 is doped with Si, and the Si doping concentration is 5 × 10⁻⁶. 18 cm-3 The thickness of the N-type GaN layer 5 is 1.8 μm.
[0081] The stress relief layer 6 has a periodic structure with 5 periods. Each period consists of sequentially stacked InGaN and Si-doped GaN layers. The InGaN layer contains 0.15% In, and the Si-doped GaN layer has a doping concentration of 5 × 10⁻⁶. 17 cm -3 The thickness of a single InGaN layer is 4.5 nm, and the thickness of a single Si-doped GaN layer is 8.5 nm.
[0082] Among them, the multi-quantum-well layer 7 consists of alternating stacked InGaN quantum well layers, GaN capping layers, and Si-doped GaN quantum barrier layers, with a period number of 9. The In composition of the InGaN quantum well layer is 0.23%, the thickness of a single InGaN quantum well layer is 3 nm, the thickness of a single GaN capping layer is 1.45 nm, and the Si doping concentration in the Si-doped GaN quantum barrier layer is 3 × 10⁻⁶. 17 cm -3 The thickness of a single Si-doped GaN quantum barrier layer is 13 nm.
[0083] The electron blocking layer 8 is an AlGaN layer, but is not limited to it. The electron blocking layer 8 has a thickness of 50 nm and an Al content of 0.59%.
[0084] The doping element in the p-type GaN layer 9 is Mg, but it is not limited to this. The doping concentration of Mg in the p-type GaN layer 9 is 1×10⁻⁶. 19 cm -3 The thickness of the p-type GaN layer 9 is 100 nm.
[0085] The method for fabricating an epitaxial wafer for a light-emitting diode in this embodiment includes the following steps:
[0086] (1) Provide a substrate;
[0087] (2) A composite transition layer is grown on the substrate;
[0088] Specifically, in MOCVD, In is periodically and sequentially grown in layers. x Al 1-x N-layer, Mg-doped InN-layer, In y Ga 1-y An N-layer and a GaN-layer are used to form a composite transition layer. In... x Al 1-xThe N-layer was grown at 870℃ and 150 torr at a pressure of 150 torr. During growth, NH3 was introduced as the N source, TMIn as the In source, and TMAl as the Al source in the MOCVD reaction chamber, with N2 as the carrier gas. The Mg-doped InN-layer was grown at 720℃ and 150 torr at a pressure of 150 torr. During growth, NH3 was introduced as the N source, TMIn as the In source, and CP2Mg as the Mg doping source in the MOCVD reaction chamber, with N2 as the carrier gas. y Ga 1-y The N-layer was grown at 780℃ and the growth pressure was 150 torr. During growth, NH3 was introduced as the N source, N2 as the carrier gas, TMGa as the Ga source, and TMIn as the In source in the MOCVD reaction chamber. Specifically, the GaN layer was grown at 780℃ and the growth pressure was 150 torr. During growth, NH3 was introduced as the N source, N2 as the carrier gas, and TMGa as the Ga source in the MOCVD reaction chamber.
[0089] (3) An intrinsic GaN layer is grown on the composite transition layer;
[0090] Specifically, an intrinsic GaN layer was grown in MOCVD at a growth temperature of 1120℃ and a growth pressure of 200 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source; H2 and N2 were used as carrier gases, and TMGa was introduced as the Ga source.
[0091] (4) Grow a U-shaped GaN layer on the intrinsic GaN layer;
[0092] Specifically, a U-shaped GaN layer was grown in MOCVD at a growth temperature of 1150℃ and a growth pressure of 200 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source, H2 and N2 were used as carrier gases, and TMGa was introduced as the Ga source.
[0093] (5) Growing an N-type GaN layer on an intrinsic GaN layer;
[0094] Specifically, an N-type GaN layer was grown in MOCVD at a temperature of 1050℃ and a pressure of 120 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source, and SiH4 was introduced as the N-type dopant source; N2 was used as the carrier gas, and TMGa was introduced as the Ga source.
[0095] (6) A stress-relieving layer is grown on the N-type GaN layer;
[0096] Specifically, InGaN and Si-doped GaN layers are periodically grown in MOCVD to form stress-relieving layers. The InGaN layer is grown at 830℃ and 150 torr at a pressure of 150 torr. During growth, NH3 is introduced as the N source, N2 as the carrier gas, TEGa as the Ga source, and TMI as the In source in the MOCVD reaction chamber. The Si-doped GaN layer is grown at 870℃ and 150 torr at a pressure of 150 torr. During growth, NH3 is introduced as the N source, SiH4 as the Si source, N2 and H2 as the carrier gases, and TEGa as the Ga source in the MOCVD reaction chamber.
[0097] (7) Grow a multi-quantum well layer on the stress relief layer;
[0098] Specifically, an InGaN quantum well layer, a GaN capping layer, and a Si-doped GaN quantum barrier layer are periodically grown in MOCVD to form a multi-quantum well layer. The InGaN quantum well layer is grown at 730℃ and 120 torr. During growth, NH3 is introduced as the N source, N2 as the carrier gas, TEGa as the Ga source, and TMI as the In source in the MOCVD reaction chamber. Similarly, the GaN capping layer is grown at 730℃ and 120 torr. During growth, NH3 is introduced as the N source, H2 and N2 as the carrier gases, and TEGa as the Ga source in the MOCVD reaction chamber. The Si-doped GaN quantum barrier layer is grown at 880℃ and 150 torr. During growth, NH3 is introduced as the N source, SiH4 as the Si source, H2 and N2 as the carrier gases, and TEGa as the Ga source in the MOCVD reaction chamber.
[0099] (8) Grow an electron blocking layer on a multi-quantum-well layer;
[0100] Specifically, an AlGaN layer was grown in MOCVD as an electron blocking layer. The growth temperature was 950℃ and the growth pressure was 120 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source, N2 as the carrier gas, TMAl as the Al source, and TEGa as the Ga source.
[0101] (9) Grow a P-type GaN layer on the electron blocking layer;
[0102] Specifically, a P-type GaN layer was grown in MOCVD at a temperature of 900℃ and a pressure of 300 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source, and CP2Mg was introduced as the P-type doping source; H2 and N2 were used as carrier gases, and TMGa was introduced as the Ga source.
[0103] Example 2
[0104] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 1 in that, In x Al 1-x In layer N, 21, x is 0.04, In y Ga 1-y In layer N23, y is 0.1, and the rest are the same as in Example 1.
[0105] Example 3
[0106] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 2 in that the Mg doping concentration in the Mg-doped InN layer 22 is 2 × 10⁻⁶. 17 cm -3 Everything else is the same as in Example 2.
[0107] Example 4
[0108] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 3 in that, In x Al 1-x The thickness of N layer 21 is 16 nm, and the thickness of Mg-doped InN layer 22 is 0.3 nm. y Ga 1-y The thickness of the N layer 23 is 12 nm, and the thickness of the GaN layer 24 is 16 nm. Everything else is the same as in Example 3.
[0109] Example 5
[0110] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 4 in that, In x Al 1-x The growth temperature of layer N21 was 830°C. Everything else was the same as in Example 4.
[0111] Example 6
[0112] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 5 in that the GaN layer 24 is grown at a temperature of 820°C. All other aspects are the same as in Embodiment 5.
[0113] Comparative Example 1
[0114] This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that the composite transition layer 2 does not include the Mg-doped InN layer 22 and the In... y Ga 1-y N layer 23 and GaN layer 24, and In x Al 1-x In layer N, x is 0. Accordingly, the preparation method does not include the preparation steps of the above three layers. Everything else is the same as in Example 1.
[0115] Comparative Example 2
[0116] This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that the composite transition layer 2 does not include In. y Ga 1-y N-layer 23 and GaN-layer 24. Correspondingly, the preparation method does not include the steps for preparing these two layers. Everything else is the same as in Example 1.
[0117] Comparative Example 3
[0118] This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that the composite transition layer 2 does not include a GaN layer 24. Correspondingly, the fabrication method does not include the step of fabricating this layer. Everything else is the same as in Example 1.
[0119] Comparative Example 4
[0120] This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that x = y = 0.05. Everything else is the same as in Example 1.
[0121] The epitaxial wafers of the light-emitting diodes obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were tested. The specific test methods are as follows:
[0122] (1) The epitaxial wafer was fabricated into a chip with a size of 10mil×24mil, and its luminous brightness was tested under a current of 120mA;
[0123] (2) Antistatic capability test: The antistatic performance of the base chip was tested using an electrostatic meter under the HBM (Human Body Discharge Model) model. The percentage of chips that could withstand 6000V reverse static electricity was tested.
[0124] The specific results are as follows:
[0125] Luminous intensity (120mA) / mW Antistatic capability (-6000V) Example 1 197.1 97.1％ Example 2 197.4 97.3％ Example 3 198.2 97.5％ Example 4 198.9 97.9％ Example 5 199.4 98.2％ Example 6 199.8 98.5％ Comparative Example 1 195.3 95.8％ Comparative Example 2 195.5 96.1％ Comparative Example 3 196.1 96.7％ Comparative Example 4 196.3 96.9％
[0126] As can be seen from the table, when the composite transition layer structure of the present invention is added to the conventional light-emitting diode structure (Comparative Example 1), the luminous brightness increases from 195.3mW to 197.1mW, and the antistatic capability increases from 95.8% to 97.1%, indicating that the composite transition layer of the present invention can improve luminous efficiency and antistatic capability.
[0127] Furthermore, a comparison between Example 1 and Comparative Examples 2 to 4 shows that when the composite transition layer structure in this invention is modified, it is difficult to effectively improve brightness and enhance antistatic capabilities.
[0128] The above description is a preferred embodiment of the invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the invention, and these improvements and modifications are also considered to be within the scope of protection of the invention.
Claims
1. A light-emitting diode epitaxial wafer, characterized in that, The system includes a substrate and a composite transition layer, an intrinsic GaN layer, a U-type GaN layer, an N-type GaN layer, a stress-relieving layer, a multiple quantum well layer, an electron blocking layer, and a P-type GaN layer sequentially disposed on the substrate. The composite transition layer has a periodic structure with 1 to 4 periods, and each period includes sequentially stacked In layers. x Al 1-x N-layer, Mg-doped InN-layer, In y Ga 1-y N-layer and GaN-layer; Where x < 0.1, y < 0.2, x < y; The In x Al 1-x The growth temperature of the N layer is ≥800℃; The Mg doping concentration in the Mg-doped InN layer is <5×10⁻⁶. 17 cm -3 ; The thickness of the Mg-doped InN layer is <1 nm; The growth temperature of the GaN layer is ≤850℃.
2. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, x is 0 to 0.05, and y is 0.05 to 0.
15.
3. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The In x Al 1-x The growth temperature of the N layer is 800℃~850℃.
4. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The Mg doping concentration in the Mg-doped InN layer is 1.2 × 10⁻⁶. 17 cm -3 ~3.5×10 17 cm -3 .
5. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The thickness of the Mg-doped InN layer is 0.1 nm to 0.5 nm.
6. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The growth temperature of the GaN layer is 800℃~850℃.
7. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The In x Al 1-x The thickness of the N layer is 10nm to 20nm, and the In y Ga 1-y The thickness of the N layer is 8nm to 15nm, and the thickness of the GaN layer is 10nm to 20nm.
8. A method for preparing a light-emitting diode epitaxial wafer, used to prepare a light-emitting diode epitaxial wafer as described in any one of claims 1 to 7, characterized in that, include: A substrate is provided on which a composite transition layer, an intrinsic GaN layer, a U-type GaN layer, an N-type GaN layer, a stress-relieving layer, a multiple quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially grown. The composite transition layer has a periodic structure with 1 to 4 periods, and each period includes sequentially stacked In layers. x Al 1-x N-layer, Mg-doped InN-layer, In y Ga 1-y N-layer and GaN-layer; Where x < 0.1, y < 0.2, x < y; The In x Al 1-x The growth temperature of the N layer is ≥800℃; The Mg doping concentration in the Mg-doped InN layer is <5×10⁻⁶. 17 cm -3 ; The thickness of the Mg-doped InN layer is <1 nm; The growth temperature of the GaN layer is ≤850℃.
9. The method for fabricating a light-emitting diode epitaxial wafer as described in claim 8, characterized in that, The In x Al 1-x The growth pressure of the N layer is 100 torr to 200 torr; The growth temperature of the Mg-doped InN layer is 700℃~750℃, and the growth pressure is 100 torr~200 torr. The In y Ga 1-y The growth temperature of the N layer is 750℃~800℃, and the growth pressure is 100 torr~200 torr; The growth pressure of the GaN layer is 100 to 200 torr.
10. A light-emitting diode, characterized in that, Includes the light-emitting diode epitaxial wafer as described in any one of claims 1 to 7.