Gan-based blue-green LED epitaxial structure and preparation method therefor

Abstract

A GaN-based blue-green LED epitaxial structure, relating to the field of semiconductor photoelectric devices. The GaN-based blue-green LED epitaxial structure comprises a substrate, and a buffer layer, a dislocation regulation layer, a U-GaN layer, an N-GaN layer, a multi-quantum-well layer, an electron blocking layer and a P-GaN layer which are sequentially stacked on the substrate, wherein the dislocation regulation layer is of a periodic structure with the number of periods ranging from 2 to 10, and each period comprises a GaN layer and an Si-doped GaN layer that are sequentially stacked. The crystal quality of the epitaxial structure can be improved, thereby improving the light-emitting efficiency and the antistatic performance of the blue-green LED based on the epitaxial structure.

Description

GaN-based blue-green LED epitaxial structure and preparation method thereof Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronic devices, and in particular to a GaN-based blue-green light LED epitaxial structure and a preparation method thereof. Background Art

[0002] The quality of GaN currently grown is poor, with a high dislocation density. This is primarily due to the lack of suitable lattice-matched substrates. A fundamental solution to this problem requires the successful production of large-area single crystals of group III nitrides. Currently, some GaN single crystal substrates are either too small and expensive, or they themselves have a high dislocation density. Therefore, heterogeneous substrates are currently the only viable option for epitaxial growth of GaN. GaN has been grown on both C-plane sapphire and R-plane sapphire substrates with varying degrees of mismatch, and improvements to the buffer layer have significantly improved the quality of the crystals. Based on the successful experience with epitaxial growth of GaAs on Si substrates, a suitable buffer layer is indeed crucial in heteroepitaxial growth.

[0003] Traditional LED epitaxy uses low-temperature GaN or AlN as a buffer layer, and then increases the temperature to grow high-quality GaN. GaN or AlN as a buffer layer does play a good buffering role for the subsequent GaN growth, effectively controlling the epitaxial dislocation density and effectively improving the crystal quality of GaN. However, this method is difficult to grasp the relationship between the high-temperature GaN layer and the buffer layer. When growing GaN at high temperature, the temperature is too high, which has a very negative impact on the GaN or AlN buffer layer. In particular, it is difficult to obtain high-quality GaN and control the surface morphology of the GaN epitaxial surface after growing a low-temperature GaN buffer layer on a PSS substrate.

[0004] Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a GaN-based blue-green light LED epitaxial structure and a preparation method thereof, which can effectively improve the crystal quality of the epitaxial structure, thereby improving the luminous efficiency and antistatic performance.

[0006] In order to solve the above problems, the present invention discloses a GaN-based blue-green LED epitaxial structure, which includes a substrate and a buffer layer, a dislocation control layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer and a P-GaN layer stacked on the substrate in sequence;

[0007] The dislocation control layer is a periodic structure with a period number of 2 to 10, and each period includes a GaN layer and a Si-doped GaN layer stacked in sequence.

[0008] As an improvement of the above technical solution, the thickness of the GaN layer is 60nm to 80nm, the thickness of the Si-doped GaN layer is 30nm to 40nm, and the Si doping concentration is 1×10 16 atoms / cm 3 ~1×10 18 atoms / cm 3 .

[0009] As an improvement of the above technical solution, the number of periods of the dislocation control layer is 5 to 10, and the thickness of the dislocation control layer is 0.5 μm to 1.5 μm;

[0010] The Si doping concentration in the Si-doped GaN layer is 1×10 17 atoms / cm 3 ~9×10 17 atoms / cm 3 .

[0011] As an improvement of the above technical solution, the multi-quantum well layer includes a shallow well layer and an active layer sequentially stacked on the N-GaN layer;

[0012] The shallow well layer is a periodic structure with a period number of 3 to 20. Each period of the shallow well layer includes sequentially stacked In x Ga 1-x N potential well layer and GaN barrier layer;

[0013] The active layer is a periodic structure with a period number of 6 to 20. Each period of the active layer includes sequentially stacked In y Ga 1-y N potential well layer and n-type doped GaN barrier layer;

[0014] Among them, x is 0.01~0.1, and y is 0.2~0.5.

[0015] As an improvement of the above technical solution, the In x Ga 1-x The thickness of the N potential well layer is 1nm to 5nm, and the thickness of the GaN barrier layer is 10nm to 30nm; y Ga 1-y The thickness of the N-type potential well layer is 2nm-5nm, and the thickness of the n-type doped GaN barrier layer is 5nm-15nm.

[0016] As an improvement of the above technical solution, it also includes a hole injection layer and a contact layer;

[0017] The hole injection layer is a low-temperature p-GaN layer, which is arranged between the multi-quantum well layer and the electron blocking layer; its thickness is 20nm to 120nm, and the Mg doping concentration is 1×1018 atoms / cm 3 ~1×10 20 atoms / cm 3 .

[0018] The contact layer is a heavily doped p-GaN layer, which is provided on the P-GaN layer and has a thickness of 2nm to 10nm and a Mg doping concentration of 1×10 20 atoms / cm 3 ~1×10 22 atoms / cm 3 .

[0019] Correspondingly, the present invention also discloses a method for preparing a GaN-based blue-green LED epitaxial structure, which is used to prepare the above-mentioned GaN-based blue-green LED epitaxial structure, and comprises:

[0020] Providing a substrate, and sequentially growing a buffer layer, a dislocation control layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer, and a P-GaN layer on the substrate;

[0021] The dislocation control layer is a periodic structure with a period number of 2 to 10, and each period includes a GaN layer and a Si-doped GaN layer stacked in sequence.

[0022] As an improvement of the above technical solution, the growth temperature of the dislocation control layer is 900° C. to 1100° C., the growth pressure is 200 torr to 500 torr, and the V / III ratio is 500 to 2500.

[0023] As an improvement of the above technical solution, the multi-quantum well layer includes a shallow well layer and an active layer sequentially stacked on the N-GaN layer; the shallow well layer includes In x Ga 1-x N potential well layer and GaN barrier layer; the active layer includes In y Ga 1-y N potential well layer and n-type doped GaN barrier layer;

[0024] In x Ga 1-x The growth temperature of the N potential well layer is 850°C to 950°C, the growth pressure is 100 torr to 500 torr, and the V / III ratio is 500 to 10000;

[0025] The growth temperature of the GaN barrier layer is 850° C. to 950° C., the growth pressure is 100 torr to 500 torr, and the V / III ratio is 500 to 10000;

[0026] In y Ga 1-yThe growth temperature of the N potential well layer is 750°C to 850°C, the growth pressure is 100 torr to 500 torr, and the V / III ratio is 2000 to 20000;

[0027] The growth temperature of the n-type doped GaN barrier layer is 850° C. to 950° C., the growth pressure is 100 torr to 500 torr, and the V / III ratio is 2000 to 20000.

[0028] As an improvement of the above technical solution, the GaN-based blue-green LED epitaxial structure further includes a hole injection layer and a contact layer;

[0029] The hole injection layer has a growth temperature of 650°C to 800°C, a growth pressure of 100 torr to 500 torr, and a V / III ratio of 500 to 3500;

[0030] The growth temperature of the contact layer is 650° C. to 850° C., the growth pressure is 100 torr to 500 torr, and the V / III ratio is 10,000 to 20,000.

[0031] The implementation of the present invention has the following beneficial effects:

[0032] In the GaN-based blue-green light-emitting diode epitaxial structure of the present invention, a dislocation control layer is inserted between the buffer layer and the U-GaN layer. This structure is a periodic structure, with each period comprising a sequentially stacked GaN layer and a Si-doped GaN layer. This dislocation control layer effectively reduces the lattice mismatch between the substrate and the GaN epitaxial layer, effectively lowering the GaN epitaxial dislocation density and improving the surface morphology of the GaN epitaxial layer, thereby effectively improving the crystal quality of the GaN and enhancing the antistatic strength and luminous efficiency of the light-emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic structural diagram of a GaN-based blue-green LED epitaxial structure according to an embodiment of the present invention;

[0034] FIG2 is a schematic structural diagram of a multi-quantum well layer in one embodiment of the present invention;

[0035] FIG3 is a flow chart of a method for preparing a GaN-based blue-green LED epitaxial structure in one embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0037] 1 and 2 , the present invention discloses a GaN-based blue-green LED epitaxial structure, comprising a substrate 1 and a buffer layer 2, a dislocation control layer 3, a U-GaN layer 4, an N-GaN layer 5, a multi-quantum well layer 6, an electron blocking layer 7, and a P-GaN layer 8 sequentially arranged on the substrate 1 .

[0038] The dislocation control layer 3 has a periodic structure with a period number of 2 to 10, and each period includes a GaN layer 31 and a Si-doped GaN layer 32 stacked in sequence. Si doping can effectively fill Ga vacancy defects in the GaN epitaxial layer, more effectively reducing the lattice mismatch between the substrate and the subsequently grown GaN epitaxial layer, more effectively alleviating the compressive stress generated by the growing GaN, improving the surface morphology of the GaN epitaxial layer, and enhancing the crystal quality of the GaN epitaxial layer, thereby reducing epitaxial defects in the 6-light-emitting region and improving the antistatic strength and luminous intensity of the LED.

[0039] Specifically, the thickness of the GaN layer 31 is 60 nm to 80 nm, the thickness of the Si-doped GaN layer 32 is 30 nm to 40 nm, and the Si doping concentration is 1×10 16 atoms / cm 3 ~1×10 18 atoms / cm 3 Preferably, the thickness of the GaN layer 31 is 60 nm to 70 nm, the thickness of the Si-doped GaN layer 32 is 30 nm to 35 nm, and the Si doping concentration is 1×10 17 atoms / cm 3 ~9×10 17 atoms / cm 3 The number of periods of the dislocation control layer 3 is controlled to be 5 to 10, and the thickness of the dislocation control layer 3 is 0.5 μm to 1.5 μm. Based on the above composition of the dislocation control layer 3, the crystal quality of the epitaxial structure can be further optimized and the luminous efficiency can be improved.

[0040] Specifically, the multi-quantum well layer 6 is a common InGaN-GaN quantum well structure or an InGaN-Si doped GaN quantum well structure in the art, but is not limited thereto. Preferably, in one embodiment of the present invention, referring to FIG2 , the multi-quantum well layer 6 includes a shallow well layer 61 and an active layer 62 sequentially stacked on the N-GaN layer; the shallow well layer 61 is a periodic structure with a period number of 3 to 20, and each period of the shallow well layer 61 includes sequentially stacked InGaN layers. x Ga 1-x N potential well layer 611 (x = 0.01 ~ 0.1) and GaN barrier layer 612. The active layer 62 is a periodic structure with a period number of 6 to 20. Each period of the active layer 62 includes sequentially stacked In y Ga 1-yN-type doped GaN barrier layer 622 and N-type doped GaN barrier layer 621. Based on the multi-quantum well layer 6 of the above structure, the shallow well layer 61 can effectively buffer the compressive strain of the active layer 62, reduce the polarization electric field strength, increase the probability of electron-hole recombination, and improve the luminous efficiency. Furthermore, by using the n-type doped GaN barrier layer 622 in the active layer 62, the polarization electric field strength can be further reduced. Therefore, based on the above layer combination, In y Ga 1-y The N-well layer 621 may have a relatively high In composition (ie, y=0.2-0.5), which effectively solves the Green Gap problem.

[0041] Specifically, x Ga 1-x The thickness of the N potential well layer 611 is 1 nm to 5 nm, and the thickness of the GaN barrier layer 612 is 10 nm to 30 nm; y Ga 1-y The thickness of the N-type well layer 621 is 2 nm to 5 nm, the thickness of the n-type doped GaN barrier layer 622 is 5 nm to 15 nm, and the Si doping concentration is 1×10 17 atoms / cm 3 ~1×10 18 atoms / cm 3 , but not limited thereto. Preferably, In x Ga 1-x The thickness of the N well layer 611 is 1 nm to 3 nm, and the thickness of the GaN barrier layer 612 is 10 nm to 15 nm; y Ga 1-y The thickness of the N-type well layer 621 is 3 nm to 5 nm, and the thickness of the n-type doped GaN barrier layer 622 is 8 nm to 15 nm.

[0042] Preferably, in one embodiment of the present invention, the epitaxial structure further includes a hole injection layer 9, which is disposed between the multi-quantum well layer 6 and the electron blocking layer 7, and can inject holes into the multi-quantum well layer 6 to improve the luminous efficiency. Specifically, the hole injection layer 9 is a low-temperature p-GaN layer with a thickness of 20nm to 100nm and a Mg doping concentration of 1×10 18 atoms / cm 3 ~1×10 20 atoms / cm 3 .

[0043] Preferably, in one embodiment of the present invention, the epitaxial structure further includes a contact layer 10, which is a heavily doped p-GaN layer, provided on the P-GaN layer 8, with a thickness of 2nm to 10nm and a Mg doping concentration of 1×10 20 atoms / cm 3~1×10 22 atoms / cm 3 The contact layer optimizes the ohmic contact between the epitaxial structure and the LED electrodes.

[0044] The substrate 1 may be a sapphire substrate, a silicon substrate or a SiC substrate, but is not limited thereto, and is preferably a sapphire substrate.

[0045] The buffer layer 2 is an AlN layer or an AlGaN layer, but is not limited thereto. Preferably, the buffer layer 2 is a stacked structure of an AlN layer and an AlGaN layer, wherein the thickness of the AlN layer is 10 nm to 50 nm, and the thickness of the AlGaN layer is 10 nm to 300 nm.

[0046] The thickness of the U-GaN layer 4 is 0.5 μm to 2.0 μm.

[0047] The doping element of the N-GaN layer 5 is Si, but not limited thereto. The doping concentration of the N-GaN layer 5 is 1×10 18 atoms / cm 3 ~1×10 21 atoms / cm 3 The thickness of the N-GaN layer 5 is 1 μm to 2.5 μm.

[0048] The electron blocking layer 7 is a p-AlGaN layer, but is not limited thereto. The molar content of Al in the electron blocking layer is 5% to 30%, the thickness is 20nm to 130nm, and the Mg doping concentration is 5×10 17 atoms / cm 3 ~5×10 19 atoms / cm 3 .

[0049] The doping element of the P-GaN layer 8 is Mg, but not limited thereto. The doping concentration of Mg in the P-GaN layer 8 is 5×10 18 atoms / cm 3 ~5×10 20 atoms / cm 3 The thickness of the P-GaN layer 8 is 30 nm to 300 nm.

[0050] Correspondingly, referring to FIG3 , the present invention further discloses a method for preparing a light-emitting diode epitaxial wafer, which is used to prepare the above-mentioned light-emitting diode epitaxial wafer, and comprises the following steps:

[0051] S1: providing a substrate;

[0052] S2: growing a buffer layer on the substrate;

[0053] Specifically, in one embodiment, step S2 includes:

[0054] S21: growing an AlN layer on a substrate;

[0055] Specifically, the AlN layer is grown by PVD at a growth temperature of 500° C. to 700° C. and a power of 2500W to 5000W. During the growth, Ar is used as a sputtering gas, N2 is used as a precursor, and Al is used as a sputtering target.

[0056] S22: The substrate obtained in step S21 is treated in a hydrogen atmosphere or a nitrogen atmosphere at 1000° C. to 1200° C. for 1 minute to 10 minutes.

[0057] S23: growing an AlGaN layer on the substrate obtained in step S22 to obtain a buffer layer;

[0058] Specifically, in one embodiment, the AlGaN layer is grown by MOCVD at a growth temperature of 500° C. to 900° C., a growth pressure of 100 torr to 600 torr, and a V / III ratio of 50 to 1000.

[0059] S3: growing a dislocation control layer on the buffer layer;

[0060] Specifically, in one embodiment, GaN layers and Si-doped GaN layers are periodically grown by MOCVD until a dislocation control layer is obtained.

[0061] The growth temperature of the dislocation control layer is 900° C. to 1100° C., the growth pressure is 200 torr to 500 torr, and the V / III ratio is 500 to 2500.

[0062] S4: growing a U-GaN layer on the dislocation control layer;

[0063] Specifically, in one embodiment, the U-GaN layer is grown by MOCVD at a growth temperature of 1000° C. to 1150° C., a growth pressure of 200 torr to 500 torr, and a V / III ratio of 800 to 2500.

[0064] S5: growing an N-GaN layer on the dislocation control layer;

[0065] Specifically, in one embodiment, the N-GaN layer is grown by MOCVD at a growth temperature of 1100° C. to 1150° C., a growth pressure of 200 torr to 500 torr, and a V / III ratio of 500 to 2500.

[0066] S6: growing a multi-quantum well layer on the N-GaN layer;

[0067] Specifically, in one embodiment, step S5 includes the following steps:

[0068] S61: growing a shallow well layer on the N-GaN layer;

[0069] Specifically, in one embodiment, In is periodically grown by MOCVD. x Ga 1-x N potential well layer and GaN barrier layer until a shallow well layer is obtained.

[0070] Specifically, x Ga 1-x The growth temperature of the N well layer is 850°C to 950°C, the growth pressure is 100torr to 500torr, and the V / III ratio is 500 to 10,000; the growth temperature of the GaN barrier layer is 850°C to 950°C, the growth pressure is 100torr to 500torr, and the V / III ratio is 500 to 10,000.

[0071] S62: growing an active layer on the shallow well layer to obtain a multi-quantum well layer;

[0072] Specifically, in one embodiment, In is periodically grown by MOCVD. y Ga 1-y N potential well layer and n-type doped GaN barrier layer until the active layer is obtained.

[0073] Specifically, y Ga 1-y The growth temperature of the N-type well layer is 750°C to 850°C, the growth pressure is 100torr to 500torr, and the V / III ratio is 2000 to 20000. The growth temperature of the n-type doped GaN barrier layer is 850°C to 950°C, the growth pressure is 100torr to 500torr, and the V / III ratio is 2000 to 20000.

[0074] S7: growing a hole injection layer on the multi-quantum well layer;

[0075] Specifically, in one embodiment, a low-temperature p-GaN layer is grown by MOCVD as a hole injection layer, with a growth temperature of 650° C. to 800° C., a growth pressure of 100 torr to 500 torr, and a V / III ratio of 500 to 3500.

[0076] S8: growing an electron blocking layer on the hole injection layer;

[0077] Specifically, in one embodiment, a p-AlGaN layer is grown by MOCVD as an electron blocking layer at a growth temperature of 900° C. to 1000° C., a growth pressure of 50 torr to 300 torr, and a V / III ratio of 500 to 10,000.

[0078] S9: growing a P-GaN layer on the electron blocking layer;

[0079] Specifically, in one embodiment, the P-GaN layer is grown by MOCVD at a growth temperature of 900° C. to 1000° C., a growth pressure of 100 torr to 500 torr, and a V / III ratio of 500 to 3500.

[0080] S10: growing a contact layer on the P-GaN layer;

[0081] Specifically, in one embodiment, a heavily doped p-GaN layer is grown by MOCVD as the contact layer at a growth temperature of 650° C. to 800° C., a growth pressure of 100 torr to 500 torr, and a V / III ratio of 10,000 to 20,000.

[0082] Preferably, in one embodiment, the method further includes annealing at 600° C. to 900° C. for 3 to 15 minutes to obtain a finished GaN-based blue-green light emitting diode epitaxial structure.

[0083] The present invention will be further described below with specific embodiments:

[0084] Example 1

[0085] This embodiment provides a GaN-based blue-green light emitting diode epitaxial structure, which includes a substrate 1 and a buffer layer 2, a dislocation control layer 3, a U-GaN layer 4, an N-GaN layer 5, a multi-quantum well layer 6, an electron blocking layer 7 and a P-GaN layer 8 sequentially arranged on the substrate 1.

[0086] The substrate 1 is a sapphire substrate, and the buffer layer 2 includes an AlN layer and an AlGaN layer sequentially stacked on the substrate 1 . The thickness of the AlN layer is 17 nm, and the thickness of the AlGaN layer is 25 nm.

[0087] The dislocation control layer 3 has a periodic structure with 10 periods. Each period includes a GaN layer 31 and a Si-doped GaN layer 32 stacked in sequence. The thickness of the GaN layer 31 is 80 nm, the thickness of the Si-doped GaN layer 32 is 40 nm, and the Si doping concentration is 1×10 18 atoms / cm 3 .

[0088] The thickness of the U-GaN layer 4 is 1.5 μm, the thickness of the N-GaN layer 5 is 2.5 μm, and the Si doping concentration is 5.5×10 19 atoms / cm 3 .

[0089] The multi-quantum well layer 6 is a periodic structure with 12 periods. Each period includes sequentially stacked In0.2 Ga 0.8 N-type well layer and n-type doped GaN barrier layer, In 0.2 Ga 0.8 The thickness of the N-type well layer is 4 nm, the thickness of the n-type doped GaN barrier layer is 12 nm, and the Si doping concentration is 5×10 17 atoms / cm 3 .

[0090] The electron blocking layer 7 is a p-AlGaN layer, but is not limited thereto. The Al content is 25% by mole, the thickness is 40 nm, and the Mg doping concentration is 1.3×10 18 atoms / cm 3 .

[0091] The thickness of the P-GaN layer 8 is 120 nm, and the Mg doping concentration is 3.2×10 19 atoms / cm 3 .

[0092] The preparation method of the GaN-based blue-green LED epitaxial structure in this embodiment is as follows:

[0093] (1) providing a substrate;

[0094] (2) PVD was used to grow an AlN layer on the substrate, wherein the growth temperature was 540°C, the power was 4300W, Ar was used as the sputtering gas, N2 was used as the precursor, and Al was used as the sputtering target.

[0095] (3) The substrate obtained in step (2) was loaded into an MOCVD machine and treated at 1150° C. for 2 min in a nitrogen atmosphere.

[0096] (4) Growth of AlGaN layer at 750°C, 400 torr, and V / III ratio of 250;

[0097] (5) Alternately growing GaN layers and Si-doped GaN layers at 980°C, 500 torr, and a V / III ratio of 800 until a dislocation control layer is obtained.

[0098] (6) Growth of U-GaN layer at 1150°C, 300 torr, and V / III ratio of 1000;

[0099] (7) Growing an N-GaN layer at 1150°C, 300 torr, and a V / III ratio of 1000;

[0100] (8) In was grown at 800°C, 300 torr, and a V / III ratio of 10,000. 0.2 Ga 0.8An N-type well layer is formed, and then an n-type doped GaN barrier layer is grown at 900°C, 300 torr, and a V / III ratio of 10,000; the growth is repeated for 12 cycles.

[0101] (9) Growth of p-AlGaN layer at 900°C, 200 torr, and V / III ratio of 800;

[0102] (10) Growth of a P-GaN layer at 950°C, 300 torr, and a V / III ratio of 1200;

[0103] (11) Anneal at 800℃ for 10min.

[0104] Example 2

[0105] This embodiment provides a GaN-based blue-green LED epitaxial structure, which differs from the first embodiment in that:

[0106] The multi-quantum well layer 6 includes a shallow well layer 61 and an active layer 62 sequentially stacked on the N-GaN layer; the shallow well layer 61 is a periodic structure with 15 periods, and each period of the shallow well layer 61 includes sequentially stacked In 0.05 Ga 0.95 N potential well layer and GaN barrier layer. 0.05 Ga 0.95 The thickness of the N well layer is 3.5 nm, and the thickness of the GaN barrier layer is 12 nm. 0.05 Ga 0.95 The growth conditions of the N well layer are: 850° C., 200 torr, and a V / III ratio of 2000; the growth conditions of the GaN barrier layer are: 850° C., 200 torr, and a V / III ratio of 1000.

[0107] The active layer 62 is the same as the multi-quantum well layer in Example 1, and the growth conditions are also the same.

[0108] The rest are the same as in Example 1.

[0109] Example 3

[0110] This embodiment provides a GaN-based blue-green LED epitaxial structure, which differs from Embodiment 2 in that:

[0111] The epitaxial structure further includes a hole injection layer 9, which is arranged between the multi-quantum well layer 6 and the electron blocking layer 7. The hole injection layer 9 is a low-temperature p-GaN layer with a thickness of 50 nm and a Mg doping concentration of 5.5×10 18 atoms / cm 3 The growth conditions are: 700℃, 200torr, V / III ratio of 800.

[0112] In addition, the epitaxial structure further includes a contact layer 10, which is provided on the P-GaN layer 8 and has a thickness of 8 nm and a Mg doping concentration of 6.8×10 20 atoms / cm 3 The growth conditions are: 780℃, 300torr, and V / III ratio of 15000.

[0113] The rest are the same as in Example 2.

[0114] Comparative Example 1

[0115] This comparative example provides a GaN-based blue-green LED epitaxial structure, which differs from Example 1 in that:

[0116] The dislocation control layer is not included.

[0117] The rest are the same as in Example 1.

[0118] Comparative Example 2

[0119] This comparative example provides a GaN-based blue-green LED epitaxial structure, which differs from Example 1 in that:

[0120] The dislocation control layer does not include a GaN layer.

[0121] The rest are the same as in Example 1.

[0122] Comparative Example 3

[0123] This comparative example provides a GaN-based blue-green LED epitaxial structure, which differs from Example 1 in that:

[0124] The dislocation control layer does not include a Si-doped GaN layer.

[0125] The rest are the same as in Example 1.

[0126] The epitaxial structures obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were tested. The specific testing methods are as follows:

[0127] (1) Prepare the epitaxial wafer into a 5 mil × 7 mil horizontal structure chip and test its luminous brightness at 20 mA;

[0128] (2) Antistatic capability test: The antistatic performance of the base chip is tested using an electrostatic meter under the HBM (Human Body Model) model to test the pass rate of the chip that can withstand reverse 4000V static electricity;

[0129] The specific results are as follows:

[0130] The above is a preferred embodiment of the invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the invention. These improvements and modifications are also regarded as protection for the present invention.

Claims

1. A GaN-based blue / green LED epitaxial structure, characterized in that, It includes a substrate, and a buffer layer, a dislocation control layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer, and a P-GaN layer that are sequentially stacked on the substrate; Among them, the dislocation control layer is a periodic structure with the number of periods being 2 to 10, and each period includes a GaN layer and a Si-doped GaN layer that are sequentially stacked.

2. The GaN-based blue / green LED epitaxial structure according to claim 1, wherein The thickness of the GaN layer is 60 nm to 80 nm, and the thickness of the Si-doped GaN layer is 30 nm to 40 nm, with its Si doping concentration being 1×10 16 atoms / cm 3 ~1×10 18 atoms / cm 3 .

3. The GaN-based blue / green light-emitting diode epitaxial structure according to claim 1, characterized in that, The number of periods of the dislocation control layer is 5 to 10, and the thickness of the dislocation control layer is 0.5 μm to 1.5 μm; The Si doping concentration in the Si-doped GaN layer is 1×10 17 atoms / cm 3 ~9×10 17 atoms / cm 3 .

4. The GaN-based blue / green light-emitting diode epitaxial structure according to any one of claims 1 to 3, characterized in that, The multi-quantum well layer includes a shallow well layer and an active layer that are sequentially stacked on the N-GaN layer; The shallow well layer is a periodic structure with the number of periods being 3 to 20, and each period of the shallow well layer includes an In x Ga 1-x N potential well layer and a GaN potential barrier layer in sequence; The active layer is a periodic structure with a period number of 6 to 20. Each period of the active layer includes an In y Ga 1-y N quantum well layer and an n-type doped GaN barrier layer in sequence; Among them, x is 0.01 to 0.1, and y is 0.2 to 0.

5.

5. The GaN-based blue / green LED epitaxial structure according to claim 4, wherein The In x Ga 1-x N potential well layer has a thickness of 1 nm to 5 nm, and the GaN barrier layer has a thickness of 10 nm to 30 nm; the In y Ga 1-y N potential well layer has a thickness of 2 nm to 5 nm, and the n-type doped GaN barrier layer has a thickness of 5 nm to 15 nm.

6. The GaN-based blue / green LED epitaxial structure according to claim 1, wherein It also includes a hole injection layer and a contact layer; The hole injection layer is a low-temperature p-GaN layer, which is disposed between the multi-quantum well layer and the electron blocking layer; its thickness is 20 nm to 120 nm, and the Mg doping concentration is 1×10 18 atoms / cm 3 ~1×10 20 atoms / cm 3 . The contact layer is a heavily doped p-GaN layer, which is disposed on the P-GaN layer, has a thickness of 2 nm to 10 nm, and an Mg doping concentration of 1×10 20 atoms / cm 3 ~1×10 22 atoms / cm 3 .

7. A method for preparing a GaN-based blue / green LED epitaxial structure, which is used to prepare the GaN-based blue / green LED epitaxial structure according to any one of claims 1 to 6, characterized in that, It includes: Providing a substrate, and sequentially growing a buffer layer, a dislocation control layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer, and a P-GaN layer on the substrate; Among them, the dislocation control layer is a periodic structure with the number of periods being 2 to 10, and each period includes a GaN layer and a Si-doped GaN layer that are sequentially stacked.

8. The preparation method of the GaN-based blue and green light-emitting diode epitaxial structure according to claim 7, characterized in that The growth temperature of the dislocation control layer is 900 °C to 1100 °C, the growth pressure is 200 torr to 500 torr, and the V / Ⅲ ratio is 500 to 2500.

9. The method for preparing a GaN-based blue / green light-emitting diode epitaxial structure according to claim 7, wherein The multiple quantum well layer includes a shallow well layer and an active layer that are sequentially stacked on the N-GaN layer; the shallow well layer includes an In x Ga 1-x N potential well layer and a GaN barrier layer; the active layer includes an In y Ga 1-y N potential well layer and an n-type doped GaN barrier layer; The In x Ga 1-x growth temperature of the N potential well layer is 850 °C to 950 °C, the growth pressure is 100 torr to 500 torr, and the V / III ratio is 500 to 10,000; The growth temperature of the GaN barrier layer is 850 °C to 950 °C, the growth pressure is 100 torr to 500 torr, and the V / Ⅲ ratio is 500 to 10000; The described In y Ga 1-y The growth temperature of the N potential well layer is 750°C to 850°C, the growth pressure is 100 torr to 500 torr, and the V / III ratio is 2000 to 20000; The growth temperature of the n-type doped GaN barrier layer is 850 °C to 950 °C, the growth pressure is 100 torr to 500 torr, and the V / Ⅲ ratio is 2000 to 20000.

10. The preparation method of the GaN-based blue / green light-emitting diode epitaxial structure according to claim 7, characterized in that, It includes: The GaN-based blue-green light-emitting diode epitaxial structure also includes a hole injection layer and a contact layer; The growth temperature of the hole injection layer is 650 °C to 800 °C, the growth pressure is 100 torr to 500 torr, and the V / Ⅲ ratio is 500 to 3500; The growth temperature of the contact layer is 650 °C to 850 °C, the growth pressure is 100 torr to 500 torr, and the V / Ⅲ ratio is 10000 to 20000.

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