Light-emitting diode epitaxial wafer, preparation method thereof and light-emitting diode

Abstract

The invention discloses a light-emitting diode epitaxial wafer, a preparation method thereof and a light-emitting diode, and relates to the field of semiconductor photoelectric devices. The light-emitting diode epitaxial wafer comprises a substrate, and a buffer layer, a non-doped GaN layer, an N-type GaN layer, a multi-quantum well layer, an end well layer, an end barrier layer, a hole transport layer, an electron barrier layer and a P-type GaN layer which are sequentially stacked on the substrate, wherein the end barrier layer comprises an AlN layer and an AlGaN layer which are stacked in sequence; the hole transport layer comprises a low-temperature Mg-doped GaN layer and a Mg-doped AlGaN layer which are alternately stacked; the electron blocking layer comprises P-type BGaN layers and P-type AlGaN layers, wherein the P-type BGaN layers and the P-type AlGaN layers are alternately stacked. By implementing the invention, the luminous efficiency can be improved.

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] In the epitaxial wafer of GaN-based light-emitting diodes, a periodic structure of InGaN / GaN or InGaN / AlGaN is generally used as the multiple quantum well layer. However, the last barrier layer (i.e., the final barrier layer) of a conventional multiple quantum well layer is prone to electron accumulation, which lowers the barrier and causes electrons to overflow from the multiple quantum well layer, resulting in nonradiative recombination in the p-type GaN layer and reducing luminous efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a light-emitting diode epitaxial wafer and its preparation method, which can improve the luminous efficiency.

[0004] Another technical problem that the present invention needs to solve is to provide a light-emitting diode.

[0005] To address the above problems, this invention discloses a light-emitting diode epitaxial wafer, which includes a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a final well layer, a final barrier layer, a hole transport layer, an electron blocking layer, and a P-type GaN layer sequentially stacked on the substrate. The final barrier layer comprises sequentially stacked AlN and AlGaN layers; the hole transport layer comprises alternately stacked low-temperature Mg-doped GaN and Mg-doped AlGaN layers; and the electron blocking layer comprises alternately stacked P-type BGaN and P-type AlGaN layers.

[0006] As an improvement to the above technical solution, the proportion of Al component in the AlGaN layer is greater than the proportion of Al component in the Mg-doped AlGaN layer; The proportion of Al component in the Mg-doped AlGaN layer is less than that in the P-type AlGaN layer.

[0007] As an improvement to the above technical solution, the thickness of the AlN layer is 1nm~5nm; and / or The Al component in the AlGaN layer accounts for 0.5~0.75%, and its thickness is 5nm~10nm; and / or The number of periods in the hole transport layer is 2 to 10; and / or The thickness of the low-temperature Mg-doped GaN layer is 2nm~5nm, and its Mg doping concentration is 1×10⁻⁶. 18 cm -3 ~8×10 18 cm -3 ; and / or The thickness of the Mg-doped AlGaN layer is 0.5 nm to 1 nm, and its Al composition ratio is 0.05% to 0.2%; its Mg doping concentration is 1 × 10⁻⁶. 18 cm -3 ~8×10 18 cm -3 ; and / or The electron blocking layer has a period number of 3 to 15; and / or The thickness of the p-type BGaN layer is 3 nm to 5 nm, the proportion of B component is 0.1% to 0.3%, and the Mg doping concentration is 5 × 10⁻⁶. 18 cm -3 ~8×10 18 cm -3 ; and / or The thickness of the p-type AlGaN layer is 1 nm to 5 nm, the Al content is 0.2% to 0.5%, and the Mg doping concentration is 5 × 10⁻⁶. 18 cm -3 ~8×10 18 cm -3 .

[0008] As an improvement to the above technical solution, the multi-quantum well layer includes alternating layers of InGaN well layers and GaN barrier layers; its period number is 3 to 15. The InGaN well layer has an In content of 0.1-0.35 and a thickness of 1-4 nm. The thickness of the GaN barrier layer is 5nm~15nm.

[0009] As an improvement to the above technical solution, the In composition ratio in the InGaN well layer is ≥0.25; An insertion layer is provided between the multiple quantum well layer and the N-type GaN layer; the insertion layer includes alternating layers of low-temperature intrinsic GaN layer and BGaN layer, wherein the proportion of B component in the BGaN layer is ≤0.2. The multi-quantum well layer forms multiple V-pits after growth, with a V-pit distribution density ≤ 1.5 × 10⁻⁶. 8 cm -2 Its opening diameter is ≥150nm.

[0010] As an improvement to the above technical solution, the distribution density of the V-shaped pits is 1.1 × 10⁻⁶. 8 cm -2 ~1.25×10 8 cm -2 Its opening diameter is 200nm~230nm; Furthermore, the V-shaped pits are filled after the electron blocking layer is grown.

[0011] Accordingly, the present invention also discloses a method for fabricating a light-emitting diode epitaxial wafer, comprising: Provide substrate; A buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a final well layer, a final barrier layer, a hole transport layer, an electron blocking layer, and a P-type GaN layer are sequentially formed on the substrate. The final barrier layer comprises sequentially stacked AlN and AlGaN layers; the hole transport layer comprises alternately stacked low-temperature Mg-doped GaN and Mg-doped AlGaN layers; and the electron blocking layer comprises alternately stacked P-type BGaN and P-type AlGaN layers.

[0012] As an improvement to the above technical solution, the growth temperature of the AlN layer is 800℃~900℃; and / or The growth temperature of the AlGaN layer is 800℃~900℃; and / or The growth temperature of the low-temperature Mg-doped GaN layer is 720℃~800℃; and / or The growth temperature of the Mg-doped AlGaN layer is 750℃~850℃; and / or The growth temperature of the P-type BGaN layer is 1000℃~1200℃; and / or The growth temperature of the P-type AlGaN layer is 1000℃~1100℃.

[0013] As an improvement to the above technical solution, an insertion layer is provided between the multi-quantum-well layer and the N-type GaN layer; the insertion layer includes alternating layers of low-temperature intrinsic GaN layer and BGaN layer; The growth temperature of the low-temperature intrinsic GaN layer is 750℃~850℃; The growth temperature of the BGaN layer is 800℃~900℃.

[0014] Accordingly, the present invention also discloses a light-emitting diode, which includes the above-described light-emitting diode epitaxial wafer.

[0015] Implementing this invention has the following beneficial effects: In one embodiment of the present invention, a light-emitting diode epitaxial wafer includes a substrate, on which a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a final well layer, a final barrier layer, a hole transport layer, an electron blocking layer, and a P-type GaN layer are sequentially stacked. The final barrier layer comprises sequentially stacked AlN and AlGaN layers; the hole transport layer comprises alternately stacked low-temperature Mg-doped GaN and Mg-doped AlGaN layers; and the electron blocking layer comprises alternately stacked P-type BGaN and P-type AlGaN layers. Based on the above-described light-emitting diode epitaxial wafer, the sequentially stacked AlN and AlGaN layers serve as a final barrier layer, reducing the lattice mismatch between the AlN and AlGaN layers and the electron blocking layer, weakening the polarization effect, reducing the negative charge generated by polarization, lowering the electron escape probability, and improving the internal quantum efficiency. Secondly, the low-temperature Mg-doped GaN layer, due to its lower H atom content, has a relatively higher hole concentration, which accelerates hole injection efficiency. Furthermore, the heterojunction structure formed by the low-temperature Mg-doped GaN layer and the Mg-doped AlGaN layer further accelerates hole injection, effectively increasing the probability of hole injection into the multi-quantum-well layer, improving the matching degree between holes and electrons in the multi-quantum-well layer, and enhancing luminescence efficiency. In addition, the Mg-doped AlGaN layer can also serve as a transition layer, further reducing lattice mismatch with the electron blocking layer and effectively preventing electron overflow to the P-type GaN layer and non-radiative coincidence. Thirdly, the higher barrier height of the P-type BGaN layer is beneficial for effectively blocking overflowing electrons. The alternating stacking structure of P-type BGaN and P-type AlGaN layers effectively reduces the barrier height for holes, minimizing hole obstruction and facilitating hole injection. Furthermore, the smaller B atom size in the P-type BGaN layer is more conducive to preventing dislocation extension during V-pit filling, improving the quality of the P-type GaN layer and thus increasing its effective hole concentration. Therefore, the epitaxial wafer of the light-emitting diode of the present invention reduces the probability of electron escape and increases the probability of hole injection into the multi-quantum-well layer, thereby effectively improving the luminous efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a light-emitting diode epitaxial wafer in one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the light-emitting diode epitaxial wafer in another embodiment of the present invention; 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.

[0017] In this diagram, 100 is the substrate, 200 is the buffer layer, 300 is the undoped GaN layer, 400 is the N-type GaN layer, 500 is the multiple quantum well layer, 510 is the InGaN well layer, 520 is the GaN barrier layer, 530 is the final well layer, 540 is the final barrier layer, 541 is the AlN layer, 542 is the AlGaN layer, 600 is the hole transport layer, 610 is the low-temperature Mg-doped GaN layer, 620 is the Mg-doped AlGaN layer, 700 is the electron blocking layer, 710 is the P-type BGaN layer, 720 is the P-type AlGaN layer, 800 is the P-type GaN layer, 900 is the insertion layer, 910 is the low-temperature intrinsic GaN layer, and 920 is the BGaN layer. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0019] See Figure 1 The present invention discloses a light-emitting diode epitaxial wafer, which includes a substrate 100, a buffer layer 200, an undoped GaN layer 300, an N-type GaN layer 400, a multiple quantum well layer 500, a final well layer 530, a final barrier layer 540, a hole transport layer 600, an electron blocking layer 700, and a P-type GaN layer 800 sequentially stacked on the substrate 100.

[0020] The final barrier layer 540 includes AlN layer 541 and AlGaN layer 542 stacked sequentially; the hole transport layer 600 includes alternating layers of low-temperature Mg-doped GaN layer 610 and Mg-doped AlGaN layer 620; and the electron blocking layer 700 includes alternating layers of P-type BGaN layer 710 and P-type AlGaN layer 720.

[0021] Based on the aforementioned LED epitaxial wafer, firstly, the sequentially stacked AlN layer 541 and AlGaN layer 542 serve as the final barrier layer 540, reducing the lattice mismatch between it and the electron blocking layer 700, weakening the polarization effect, reducing the negative charge generated by polarization, lowering the probability of electron escape, and improving the internal quantum efficiency. Secondly, the low-temperature Mg-doped GaN layer 610, due to its low H atom content, has a relatively high hole concentration, which can accelerate the hole injection efficiency; moreover, the heterojunction structure formed by the low-temperature Mg-doped GaN layer 610 and the Mg-doped AlGaN layer 620 can further accelerate the hole injection, thereby effectively increasing the probability of hole injection into the multi-quantum well layer 500, improving the matching degree of holes and electrons in the multi-quantum well layer 500, and improving the luminous efficiency. In addition, the Mg-doped AlGaN layer 620 can also serve as a transition layer, further reducing the lattice mismatch with the electron blocking layer 700, effectively preventing electron overflow to the P-type GaN layer 800 and nonradiative coincidence. Thirdly, the higher barrier height of the P-type BGaN layer 710 is beneficial for effectively blocking overflowing electrons. Furthermore, the alternating stacking structure of the P-type BGaN layer 710 and the P-type AlGaN layer 720 effectively reduces the barrier height for holes, minimizing hole blockage and facilitating hole injection. In addition, the smaller size of the boron atoms in the P-type BGaN layer 710 is more conducive to preventing dislocation propagation during V-hole filling, improving the quality of the P-type GaN layer 800 and thus increasing its effective hole concentration. Therefore, the LED epitaxial wafer of this invention reduces the probability of electron escape and increases the probability of hole injection into the multi-quantum-well layer 500, effectively improving luminous efficiency.

[0022] The AlN layer 541 has a thickness of 1 nm to 5 nm. If its thickness is too large, it will reduce the probability of holes entering the multi-quantum-well layer 500, thus reducing the luminous efficiency. For example, the thickness of the AlN layer 541 is 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, or 4 nm, but is not limited to these. Preferably, it is 2 nm to 4 nm.

[0023] The thickness of the AlGaN layer 542 is 5nm to 10nm, exemplarily 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm, 8nm, 8.5nm, or 9nm, but not limited thereto. Preferably, it is 8nm to 10nm.

[0024] In this embodiment, the proportion of Al component in the AlGaN layer 542 is ≤0.8 to prevent the barrier height from being too high and affecting hole injection. More specifically, in some embodiments, the proportion of Al component in the AlGaN layer 542 is 0.5~0.75, exemplarily 0.55, 0.6, 0.65 or 0.7, but not limited thereto. Preferably, it is 0.5~0.6.

[0025] The hole transport layer 600 has 2 to 10 cycles, exemplarily 3, 4, 5, 6, 7, 8 or 9, but is not limited thereto. Preferably, it has 5 to 10 cycles.

[0026] The thickness of the low-temperature Mg-doped GaN layer 610 is 2nm to 5nm, exemplarily 2.5nm, 3nm, 3.5nm, 4nm or 4.5nm, but not limited thereto. Preferably, it is 3nm to 5nm.

[0027] The Mg doping concentration in the low-temperature Mg-doped GaN layer 610 is 1×10⁻⁶. 18 cm -3 ~8×10 18 cm -3 For example, 1.5 × 10 18 cm -3 3×10 18 cm -3 4.5×10 18 cm -3 6×10 18 cm -3 Or 7.5×10 18 cm -3 However, it is not limited to this. Preferably, it is 5×10. 18 cm -3 ~8×10 18 cm -3 .

[0028] The thickness of the Mg-doped AlGaN layer 620 is 0.5 nm to 1 nm, exemplarily 0.6 nm, 0.7 nm, 0.8 nm or 0.9 nm, but not limited thereto. Preferably, it is 0.6 nm to 1 nm.

[0029] The Mg doping concentration in the Mg-doped AlGaN layer 620 is 1×10⁻⁶. 18 cm -3 ~8×10 18 cm -3 For example, 1.5 × 10 18 cm -3 3×10 18 cm -3 4.5×10 18 cm -3 6×10 18 cm -3 Or 7.5×10 18 cm -3 However, it is not limited to this. Preferably, it is 5×10. 18 cm -3 ~8×10 18 cm -3 .

[0030] The proportion of Al component in the Mg-doped AlGaN layer 620 is 0.05~0.2%, exemplaryly 0.08, 0.11, 0.14, 0.17 or 0.19, but not limited thereto. Preferably it is 0.1~0.2%.

[0031] The electron blocking layer 700 has 3 to 15 periods, exemplarily 4, 6, 8, 10, 12 or 14, but is not limited thereto. Preferably, it has 5 to 15 periods.

[0032] The thickness of the P-type BGaN layer 710 is 3nm to 5nm, exemplarily 3.4nm, 3.8nm, 4.2nm, 4.6nm or 4.9nm, but not limited thereto.

[0033] The proportion of B component in the p-type BGaN layer 710 is 0.1~0.3, exemplarily 0.12, 0.15, 0.18, 0.21, 0.24 or 0.27, but not limited thereto. Preferably it is 0.1~0.2.

[0034] The Mg doping concentration in the p-type BGaN layer 710 is 5 × 10⁻⁶. 18 cm -3 ~8×10 18 cm -3 For example, it is 5.4 × 10 18 cm -3 5.8×10 18 cm -3 6.2×10 18 cm -3 6.6×10 18 cm -3 7×10 18 cm -3 7.4×10 18 cm -3 Or 7.8×10 18 cm -3 However, it is not limited to this. Preferably, it is 5×10. 18 cm -3 ~7×10 18 cm -3 .

[0035] The thickness of the p-type AlGaN layer 720 is 1nm to 5nm, exemplarily 1.5nm, 2nm, 2.5nm, 3nm, 3.5nm, 4nm or 4.5nm, but not limited thereto. Preferably, it is 2nm to 5nm.

[0036] The proportion of Al component in the p-type AlGaN layer 720 is 0.2~0.5, exemplary of which are 0.25, 0.3, 0.35, 0.4 or 0.45, but not limited thereto. Preferably it is 0.3~0.5.

[0037] The Mg doping concentration in the p-type AlGaN layer 720 is 5 × 10⁻⁶. 18 cm -3 ~8×10 18 cm -3 For example, it is 5.4 × 10. 18 cm -3 5.8×10 18 cm -3 6.2×10 18 cm -3 6.6×10 18 cm -3 7×10 18 cm -3 7.4×10 18 cm -3 Or 7.8×10 18 cm -3 However, it is not limited to this. Preferably, it is 5×10. 18 cm -3 ~7×10 18 cm -3 .

[0038] The substrate 100 is a sapphire substrate or a silicon substrate, but is not limited to these.

[0039] The buffer layer 200 is an AlN layer, a GaN layer, or an AlGaN layer, but is not limited to these. The thickness of the buffer layer 200 is 30nm~80nm.

[0040] The thickness of the undoped GaN layer 300 is 1μm to 3μm.

[0041] The N-type GaN layer 400 is doped with Si, but is not limited to Si. The Si doping concentration in the N-type GaN layer 400 is 1×10⁻⁶. 18 cm -3 ~5×10 19 cm -3 Its thickness is 1μm~5μm.

[0042] The multiple quantum well layer 500 comprises alternating layers of InGaN well layers 510 and GaN barrier layers 520, with a period number of 3 to 15. Specifically, the In content of the InGaN well layer 510 is 0.1% to 0.35%, and the LED epitaxial wafer of this invention is applicable to blue and yellow-green LED structures. The thickness of the InGaN well layer 510 is 1 nm to 4 nm. The thickness of the GaN barrier layer 520 is 5 nm to 15 nm.

[0043] Among them, the final well layer 530 is an InGaN layer, which is the same as the InGaN well layer 510, with an In composition ratio of 0.1~0.35 and a thickness of 5nm~15nm.

[0044] The doping element in the p-type GaN layer 800 is Mg, but it is not limited to Mg. The doping concentration of Mg in the p-type GaN layer 800 is 1×10⁻⁶. 19 cm -3 ~5×10 20 cm -3 Its thickness is 80nm~200nm.

[0045] Preferably, in some embodiments, the proportion of Al component in AlGaN layer 542 is greater than the proportion of Al component in Mg-doped AlGaN layer 620; the proportion of Al component in Mg-doped AlGaN layer 620 is less than the proportion of Al component in p-type AlGaN layer 720. Based on this embodiment, the electron spillover probability can be further reduced, the internal quantum efficiency can be improved, and the luminescence efficiency can be increased.

[0046] Preferably, see Figure 2 In some embodiments, when the light-emitting diode epitaxial wafer is used for a green LED, i.e., when the In composition ratio in the InGaN well layer 510 and the final well layer 530 is ≥0.25, an insertion layer 900 is provided between the multi-quantum well layer 500 and the N-type GaN layer 400; the insertion layer 900 includes alternating layers of low-temperature intrinsic GaN layer 910 and BGaN layer 920, and the B composition ratio in the BGaN layer 920 is ≤0.2%; after the multi-quantum well layer 500 is grown, multiple V-pits are formed, and the distribution density of the V-pits is ≤1.5×10⁻⁶. 8 cm -2 Its opening diameter is ≥150nm. Based on the above-mentioned insertion layer 900, the distribution density of V-pits can be effectively reduced and its opening diameter increased, which is beneficial to further improve hole injection efficiency and thus improve luminescence efficiency.

[0047] Specifically, the number of cycles of the insertion layer 900 is 5 to 15, exemplarily 6, 8, 10, 12 or 14, but not limited thereto, and preferably 8 to 15.

[0048] Specifically, the thickness of the low-temperature intrinsic GaN layer 910 is 5nm to 15nm, exemplarily 8nm, 10nm, 11nm, 13nm or 14nm, but not limited thereto. Preferably, it is 8nm to 15nm.

[0049] Specifically, the thickness of the BGaN layer 920 is 3nm to 10nm, exemplarily 4nm, 6nm, or 8nm, but not limited thereto. The proportion of B component in the BGaN layer 920 is 0.1% to 0.2%, exemplarily 0.12%, 0.14%, 0.16%, or 0.18%, but not limited thereto. Preferably, it is 0.15% to 0.2%. Through the aforementioned low-temperature intrinsic GaN layer 910 and BGaN layer 920, the distribution density of V-pits can be effectively further reduced, and their opening diameter can be increased. Specifically, the distribution density of V-pits is 1.1 × 10⁻⁶. 8 cm -2 ~1.25×10 8 cm -2 Its opening diameter is 200nm~230nm.

[0050] Preferably, in some embodiments, the V-pits are filled after the electron blocking layer 700 is grown. This method improves the growth quality of the p-type GaN layer 800 and increases its effective hole concentration. It should be noted that while the sidewalls of the V-pits are generally considered to improve hole injection efficiency, the V-pit structure is often maintained during the growth of the p-type GaN layer 800. However, through extensive experimentation, the inventors have found that filling the V-pits with the electron blocking layer 700 using this technical solution results in higher luminous efficiency.

[0051] Accordingly, see Figure 3 The present invention also provides a method for preparing a light-emitting diode epitaxial wafer, which includes the following steps: S1: Provides a substrate; S2: A buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a final well layer, a final barrier layer, a hole transport layer, an electron blocking layer, and a P-type GaN layer are sequentially grown on the substrate. Specifically, in some embodiments of the present invention, step S2 includes: S21: Grow a buffer layer on the substrate; The buffer layer can be grown using PVD, MOCVD, MBE, or VPE, but is not limited to these methods.

[0052] Preferably, in one embodiment of the present invention, an AlN layer is grown by PVD as a buffer layer.

[0053] S22: Growing an undoped GaN layer on the buffer layer; Specifically, in one embodiment of the present invention, an undoped GaN layer is grown using MOCVD at a growth temperature of 1000℃~1200℃ and a growth pressure of 100 torr~500 torr.

[0054] S23: Growing an N-type GaN layer on an undoped GaN layer; Specifically, in one embodiment of the present invention, an N-type GaN layer is grown using MOCVD at a growth temperature of 1100°C to 1200°C and a growth pressure of 100 torr to 500 torr.

[0055] Preferably, in some embodiments, after growing the N-type GaN layer, an insertion layer growth step is included. Specifically, a low-temperature intrinsic GaN layer and a BGaN layer are periodically grown using MOCVD until the insertion layer is obtained. More specifically, the growth temperature of the low-temperature intrinsic GaN layer is 750°C to 850°C, and the growth pressure is 100 torr to 300 torr; the growth temperature of the BGaN layer is 800°C to 900°C, and the growth pressure is 100 torr to 300 torr.

[0056] S24: Growth of multiple quantum well layers on N-type GaN layers; Specifically, in one embodiment, InGaN well layers and GaN barrier layers are periodically grown on an N-type GaN layer by MOCVD until a multi-quantum well layer is obtained.

[0057] The quantum well layer is grown at a temperature of 720℃ to 800℃ and a growth pressure of 100 torr to 300 torr. The GaN barrier layer is grown at a temperature of 800℃ to 900℃.

[0058] S25: Growing a final well layer on a multi-quantum well layer; Specifically, in one embodiment, an InGaN layer is grown on a multi-quantum-well layer using MOCVD as the final well layer. The growth temperature is 720°C to 800°C, and the growth pressure is 100 torr to 300 torr.

[0059] S26: Grow the final barrier layer on the final trap layer; Specifically, in one embodiment, an AlN layer and an AlGaN layer are grown sequentially by MOCVD to obtain the final barrier layer. The growth temperature of the AlN layer is 800℃~900℃, and the growth pressure is 100 torr~500 torr; the growth temperature of the AlGaN layer is 800℃~900℃, and the growth pressure is 100 torr~500 torr.

[0060] S27: A hole transport layer is grown on the final barrier layer; Specifically, in one embodiment, a hole transport layer is obtained by alternating growth of a low-temperature Mg-doped GaN layer and a Mg-doped AlGaN layer using MOCVD. The growth temperature of the low-temperature Mg-doped GaN layer is 720°C to 800°C, and the growth pressure is 100 torr to 300 torr. The growth temperature of the Mg-doped AlGaN layer is 750°C to 850°C, and the growth pressure is 100 torr to 300 torr.

[0061] S28: An electron blocking layer is grown on the hole transport layer; Specifically, in one embodiment, P-type BGaN layers and P-type AlGaN layers are alternately grown by MOCVD until an electron blocking layer is obtained. The growth temperature of the P-type BGaN layer is 1000℃~1200℃, and the growth pressure is 300 torr~500 torr; the growth temperature of the P-type AlGaN layer is 1000℃~1100℃, and the growth pressure is 300 torr~500 torr.

[0062] S29: Grow a P-type GaN layer on the electron blocking layer; Specifically, in one embodiment of the present invention, a P-type GaN layer is grown using MOCVD at a growth temperature of 950°C to 1000°C and a growth pressure of 100 torr to 300 torr.

[0063] The present invention will be further described below with reference to specific embodiments: Example 1 This embodiment provides a light-emitting diode epitaxial wafer, which includes a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a final well layer, a final barrier layer, a hole transport layer, an electron blocking layer and a P-type GaN layer are sequentially stacked on the substrate. The substrate is sapphire, the buffer layer is an AlN layer with a thickness of 40 nm, and the undoped GaN layer has a thickness of 1.5 μm. The Si doping concentration in the N-type GaN layer is 8.5 × 10⁻⁶. 18 cm -3 Its thickness is 3μm.

[0064] The multi-quantum-well layer comprises alternating layers of InGaN wells and GaN barriers, with a period of 9. The InGaN well layer has an In content of 0.15% and a thickness of 3 nm; the GaN barrier layer has a thickness of 10 nm. The final well layer is an InGaN layer with an In content of 0.15% and a thickness of 3 nm.

[0065] The final barrier layer consists of sequentially stacked AlN and AlGaN layers. The AlN layer has a thickness of 2.5 nm, the AlGaN layer has a thickness of 8.5 nm, and the Al composition accounts for 0.55%.

[0066] The hole transport layer comprises alternating layers of low-temperature Mg-doped GaN and Mg-doped AlGaN, with a period of 8. The low-temperature Mg-doped GaN layer has a thickness of 4 nm and a Mg doping concentration of 5.5 × 10⁻⁶. 18 cm -3 The thickness of the Mg-doped AlGaN layer is 0.8 nm, and its Mg doping concentration is 3.5 × 10⁻⁶. 18 cm -3 Its Al component accounts for 0.2%.

[0067] The electron blocking layer comprises alternating layers of P-type BGaN and P-type AlGaN, with a period of 8. The thickness of the P-type BGaN layer is 4.5 nm, the boron content is 0.15%, and the Mg doping concentration is 6.3 × 10⁻⁶. 18 cm -3 The p-type AlGaN layer is 3 nm thick, with an Al content of 0.2% and a Mg doping concentration of 7 × 10⁻⁶. 18 cm -3 .

[0068] The p-type GaN layer has a thickness of 150 nm and a Mg doping concentration of 5.5 × 10⁻⁶. 19 cm -3 .

[0069] The method for fabricating the epitaxial wafer of the light-emitting diode in this embodiment includes the following steps: (1) Provide a substrate; (2) A buffer layer is grown on the substrate; Specifically, an AlN layer is grown using PVD as a buffer layer.

[0070] (3) Growing an undoped GaN layer on the buffer layer; Specifically, undoped GaN layers were grown using MOCVD at a growth temperature of 1120℃ and a growth pressure of 400 torr.

[0071] (4) Growing an N-type GaN layer on an undoped GaN layer; Specifically, an N-type GaN layer was grown using MOCVD at a growth temperature of 1150℃ and a growth pressure of 300 torr.

[0072] (5) Growing multiple quantum well layers on N-type GaN layers; Specifically, InGaN well layers and GaN barrier layers are alternately grown on an N-type GaN layer using MOCVD until a multi-quantum well layer is obtained. The growth temperature of the InGaN well layer is 770℃ and the growth pressure is 300 torr, while the growth temperature of the GaN barrier layer is 850℃ and the growth pressure is 300 torr.

[0073] (6) Growing a final well layer on a multi-quantum well layer; The InGaN layer was grown by MOCVD at a temperature of 770℃ and a pressure of 300 torr.

[0074] (7) Grow the final barrier layer on the final trap layer; In this process, AlN and AlGaN layers are grown sequentially using MOCVD to obtain the final barrier layer. The growth temperature of the AlN layer is 850℃ and the growth pressure is 400 torr; the growth temperature of the AlGaN layer is 880℃ and the growth pressure is 400 torr.

[0075] (8) A hole transport layer is grown on the final barrier layer; Specifically, a hole transport layer was obtained by alternating growth of low-temperature Mg-doped GaN layers and Mg-doped AlGaN layers using MOCVD. The growth temperature of the low-temperature Mg-doped GaN layer was 750℃, and the growth pressure was 200 torr. The growth temperature of the Mg-doped AlGaN layer was 820℃, and the growth pressure was 200 torr.

[0076] (9) An electron blocking layer is grown on the hole transport layer; Specifically, P-type BGaN layers and P-type AlGaN layers were alternately grown by MOCVD until an electron blocking layer was obtained. The growth temperature of the P-type BGaN layer was 1120℃ and the growth pressure was 450 torr; the growth temperature of the P-type AlGaN layer was 1080℃ and the growth pressure was 450 torr.

[0077] (10) Grow a P-type GaN layer on the electron blocking layer; Specifically, in one embodiment of the present invention, a P-type GaN layer is grown using MOCVD at a growth temperature of 980°C and a growth pressure of 200 torr.

[0078] Example 2 This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 1 in that: The Al content of the Mg-doped AlGaN layer is 0.15%. The Al content of the p-type AlGaN layer is 0.35%.

[0079] Everything else is the same as in Example 1.

[0080] Example 3 This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 2 in that: The In composition in the InGaN well layer is 0.35%, and the In composition in the end well layer is also 0.35%.

[0081] After the growth of the multi-quantum-well layer, multiple V-pits are formed, with a distribution density of 1.65 × 10⁻⁶. 8 cm -2 Its opening diameter is 125nm~140nm.

[0082] Everything else is the same as in Example 2.

[0083] Example 4 This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 3 in that: An insertion layer is provided between the multiple quantum well layer and the N-type GaN layer; the insertion layer includes alternating layers of low-temperature intrinsic GaN layer and BGaN layer, with a period number of 12. The thickness of the low-temperature intrinsic GaN layer is 10 nm, the thickness of the BGaN layer is 5 nm, and the proportion of B component is 0.18.

[0084] After the growth of the multi-quantum-well layer, multiple V-pits are formed, with a distribution density of 1.24 × 10⁻⁶. 8 cm -2 Its opening diameter is 205nm~220nm.

[0085] Comparative Example 1 This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that: The final barrier layer is a GaN layer with a thickness of 10 nm.

[0086] Furthermore, the epitaxial wafer does not include a hole transport layer, and the electron blocking layer is an AlGaN layer with a thickness of 65nm.

[0087] Everything else is the same as in Example 1.

[0088] Comparative Example 2 This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that: Excluding the hole transport layer.

[0089] Everything else is the same as in Example 1.

[0090] Comparative Example 3 This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that: Excluding the electron blocking layer, everything else is the same as in Example 1.

[0091] Comparative Example 4 This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 3 in that: The final barrier layer is a GaN layer with a thickness of 10 nm.

[0092] The epitaxial wafer does not include a hole transport layer; the electron blocking layer is an AlGaN layer with a thickness of 65 nm.

[0093] Everything else is the same as in Example 3.

[0094] The epitaxial structures obtained in Examples 1-4 and Comparative Examples 1-3 were fabricated into chips with a vertical structure size of 5 mil × 7 mil. The luminous intensity was measured at 120 mA. Using the data from Comparative Example 1 as a benchmark, the brightness improvement rate of Examples 1 and 2 was calculated. Using the data from Comparative Example 4 as a benchmark, the brightness improvement rate of Examples 3 and 4 was calculated. The specific results are shown in the table below:

[0095] 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 by, The device comprises a substrate, a buffer layer, a non-doped GaN layer, an N-type GaN layer, a multi-quantum well layer, a final well layer, a final barrier layer, a hole transport layer, an electron blocking layer and a P-type GaN layer which are sequentially stacked on the substrate; The final barrier layer comprises an AlN layer and an AlGaN layer which are sequentially stacked; the hole transport layer comprises low-temperature Mg-doped GaN layers and Mg-doped AlGaN layers which are alternately stacked; and the electron blocking layer comprises P-type BGaN layers and P-type AlGaN layers which are alternately stacked.

2. The light emitting diode epitaxial wafer of claim 1, wherein, The proportion of Al components in the AlGaN layer is greater than the proportion of Al components in the Mg-doped AlGaN layer; The proportion of Al components in the Mg-doped AlGaN layer is less than the proportion of Al components in the P-type AlGaN layer.

3. The light emitting diode epitaxial wafer of claim 1, wherein, The thickness of the AlN layer is 1-5 nm; and / or The proportion of Al components in the AlGaN layer is 0.5-0.75, and the thickness of the AlGaN layer is 5-10 nm; and / or The number of periods of the hole transport layer is 2-10; and / or The thickness of the low-temperature Mg-doped GaN layer is 2-5 nm, and the Mg doping concentration is 1x10 18 cm -3 ~8x10 18 cm -3 ; and / or The thickness of the Mg-doped AlGaN layer is 0.5-1 nm, and the proportion of Al components in the Mg-doped AlGaN layer is 0.05-0.2; having a Mg doping concentration of 1 x 10 18 cm -3 having a Mg doping concentration of 8 x 10 18 cm -3 ; and / or The number of periods of the electron blocking layer is 3-15; and / or The thickness of the P-type BGaN layer is 3-5 nm, the proportion of B component is 0.1-0.3, the Mg doping concentration is 5x10 18 cm -3 ~8x10 18 cm -3 ; and / or The thickness of the P-type AlGaN layer is 1nm-5nm, the proportion of Al component is 0.2-0.5, the Mg doping concentration is 5x10 18 cm -3 ~8x10 18 cm -3 .

4. The light emitting diode epitaxial wafer according to any one of claims 1 to 3, wherein, The multi-quantum well layer comprises InGaN well layers and GaN barrier layers which are alternately stacked; and the number of periods of the multi-quantum well layer is 3-15; The proportion of In components in the InGaN well layer is 0.1-0.35, and the thickness of the InGaN well layer is 1-4 nm; The thickness of the GaN barrier layer is 5-15 nm.

5. The light emitting diode epitaxial wafer of claim 4, wherein, The proportion of In components in the InGaN well layer is greater than or equal to 0.25; An interlayer is arranged between the multi-quantum well layer and the N-type GaN layer; the interlayer comprises low-temperature intrinsic GaN layers and BGaN layers which are alternately stacked, and the proportion of B components in the BGaN layer is less than or equal to 0.2; The multiple quantum well layer forms multiple V-pits after growth, the distribution density of the V-pits is ≤1.5×10 8 cm -2 , and the opening diameter is ≥150nm.

6. The light emitting diode epitaxial wafer of claim 4, wherein, The distribution density of the V-pits is 1.1×10 8 cm -2 -1.25×10 8 cm -2 ; the opening diameter is 200nm-230nm; And the V-pit is filled after the electron blocking layer is grown.

7. A method for fabricating a light-emitting diode epitaxial wafer, characterized in that, The device comprises: a substrate is provided; a buffer layer, a non-doped GaN layer, an N-type GaN layer, a multi-quantum well layer, a final well layer, a final barrier layer, a hole transport layer, an electron blocking layer and a P-type GaN layer are sequentially formed on the substrate; The final barrier layer comprises an AlN layer and an AlGaN layer which are sequentially stacked; the hole transport layer comprises low-temperature Mg-doped GaN layers and Mg-doped AlGaN layers which are alternately stacked; and the electron blocking layer comprises P-type BGaN layers and P-type AlGaN layers which are alternately stacked.

8. The method for fabricating a light-emitting diode epitaxial wafer as described in claim 7, characterized in that, The growth temperature of the AlN layer is 800-900℃; and / or The growth temperature of the AlGaN layer is 800-900℃; and / or The growth temperature of the low-temperature Mg-doped GaN layer is 720-800℃; and / or The growth temperature of the Mg-doped AlGaN layer is 750-850℃; and / or The growth temperature of the P-type BGaN layer is 1000-1200℃; and / or The growth temperature of the P-type AlGaN layer is 1000-1100℃.

9. The method of claim 7, wherein the epitaxial wafer is a light emitting diode epitaxial wafer. An interlayer is arranged between the multi-quantum well layer and the N-type GaN layer; the interlayer comprises low-temperature intrinsic GaN layers and BGaN layers which are alternately stacked; The growth temperature of the low-temperature intrinsic GaN layer is 750-850℃. The growth temperature of the BGaN layer is 800-900℃.

10. A light emitting diode, comprising: The application relates to a light emitting diode epitaxial wafer comprising a light emitting diode according to any one of claims 1-6.

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