Micro-LED epitaxial wafer and preparation method thereof, Micro-LED

Abstract

The present invention discloses a Micro-LED epitaxial wafer and a preparation method thereof, and Micro-LED, and relates to the field of semiconductor optoelectronic devices. The Micro-LED epitaxial wafer comprises a substrate, an N-type GaN layer, a first multi-quantum well layer, and a P-type GaN layer in sequence, wherein the first multi-quantum well layer comprises an alternately stacked quantum well layer and a first quantum barrier layer; the quantum well layer comprises a first GaN layer, a first InGaN layer, an InGaN layer, and a P-type GaN layer in sequence. x Ga 1‑ x N layer and AlN layer; the first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1‑α N layer, non-doped Al a Ga 1‑a N layer, N-type Al β Ga 1‑β N layer and the second GaN layer; the proportion of In component in the first InGaN layer increases, and its maximum value is ≤x; the Al component in the first AlGaN layer decreases, and its minimum value is ≥α. The implementation of the present invention can improve the luminous efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronic devices, and in particular to a Micro-LED epitaxial wafer and a preparation method thereof, and a Micro-LED. Background Art

[0002] Micro-LED technology is a new generation of display technology solution after LCD, OLED, and Mini-LED. It has many advantages such as high brightness, high display density, high color gamut, and low power consumption. It is the frontier research direction of current display technology. At present, the common Micro-LED epitaxial wafer is generally a GaN-based epitaxial structure, which generally uses InGaN / GaN as the quantum well active region, but because the piezoelectric field in the InGaN quantum well is as high as the MV / cm level. It will cause the separation of electrons and holes in the InGaN quantum well, resulting in a reduction in the overlap of the wave functions of electrons and holes, a longer radiation recombination lifetime, a lower radiation recombination rate, and carriers are more likely to be captured and wasted by non-radiative recombination centers, greatly reducing the luminous efficiency of the LED; secondly, this piezoelectric field will also cause the InGaN / GaN quantum well barrier band to bend and become jagged, hindering the injection of electrons and holes, aggravating the uneven distribution of electrons and holes in the quantum well region, and reducing the luminous efficiency. Summary of the invention

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

[0004] Another technical problem to be solved by the present invention is to provide a Micro-LED.

[0005] In order to solve the above problems, the present invention provides a Micro-LED epitaxial wafer, which includes a substrate, an N-type GaN layer, a first multi-quantum well layer and a P-type GaN layer sequentially stacked on the substrate, wherein the first multi-quantum well layer includes an alternately stacked quantum well layer and a first quantum barrier layer;

[0006] The quantum well layer includes a first GaN layer, a first InGaN layer, and an In x Ga 1-x The first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Al β Ga 1-β N layer and a second GaN layer;

[0007] The In component ratio of the first InGaN layer decreases from the side close to the first GaN layer to the side close to the In x Ga 1-x The N layer side changes gradually, and the maximum value of the In component ratio in the first InGaN layer is less than or equal to the In x Ga 1-x The proportion of In component in the N layer;

[0008] The Al component ratio in the first AlGaN layer decreases from the side close to the quantum well layer to the side close to the N-type Al α Ga 1-α The N-type AlGaN layer has a decreasing change, and the minimum value of the Al component ratio in the first AlGaN layer is greater than or equal to the N-type Al α Ga 1-α The proportion of Al component in the N layer.

[0009] As an improvement of the above technical solution, the In x Ga 1-x The thickness of the N layer is ≤3.5nm, and the value of x ranges from 0.1 to 0.3.

[0010] As an improvement of the above technical solution, α=a=β, the N-type Al α Ga 1-α The thickness of the N layer, the non-doped Al a Ga 1- a The thickness of the N layer, the N-type Al β Ga 1-β The ratio of the thickness of the N layer is (6~10):(0.8~1.2):(6~11);

[0011] The N-type Al α Ga 1-α The doping concentration of the N layer is β Ga 1-β The doping concentration of the N layer is the same.

[0012] As an improvement of the above technical solution, the number of periods of the first multi-quantum well layer is 2 to 10;

[0013] The thickness of the first GaN layer is 0.5nm~5nm, the thickness of the first InGaN layer is 0.1nm~1nm, and the In component ratio is 0.01~0.3; x Ga 1-x The thickness of the N layer is 1nm~4nm; the thickness of the AlN layer is 0.5nm~5nm;

[0014] The thickness of the first quantum barrier layer is 5nm-30nm, the thickness of the first AlGaN layer, the thickness of the N-type Al α Ga 1-α The thickness of the N layer, the non-doped Al a Ga 1-a The thickness of the N layer, the N-type Al β Ga 1-β The ratio of the thickness of the N layer to the thickness of the second GaN layer is (0.6-1.2): (4-12): (0.8-1.2): (4-11): (0.6-1.3);

[0015] The Al component ratio in the first AlGaN layer is 0.05-0.4, and the N-type Al α Ga 1-α The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of α is 0.05~0.3; the non-doped Al a Ga 1-a The value range of a in the N layer is 0.05~0.3; β Ga 1-β The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of β is 0.05~0.3.

[0016] As an improvement of the above technical solution, it also includes a second multi-quantum well layer disposed between the first multi-quantum well layer and the P-type GaN layer, wherein the second multi-quantum well layer includes alternately stacked quantum well layers and second quantum barrier layers;

[0017] The second quantum barrier layer includes a second AlGaN layer, an N-type Al γ Ga 1-γ N layer, non-doped Al b Ga 1- b N layer, N-type Al δ Ga 1-δ N layer and a third GaN layer;

[0018] The Al component ratio in the second AlGaN layer decreases from the side close to the quantum well layer to the side close to the N-type Al γ Ga 1-γ The N-type AlGaN layer has a decreasing change, and the minimum value of the Al component ratio in the second AlGaN layer is greater than or equal to the N-type Al γ Ga1-γ The proportion of Al component in the N layer;

[0019] γ≠α, b≠a, δ≠β.

[0020] As an improvement of the above technical solution, the N-type Al γ Ga 1-γ The doping concentration of the N layer is greater than that of the N-type Al α Ga 1-α The doping concentration of the N layer; δ Ga 1-δ The doping concentration of the N layer is greater than that of the N-type Al β Ga 1-β Doping concentration of the N layer.

[0021] As an improvement of the above technical solution, the proportion of Al component in the second AlGaN layer is less than the proportion of Al component in the first AlGaN layer, γ<α, b<a, δ<β.

[0022] As an improvement of the above technical solution, γ=b=δ, the N-type Al γ Ga 1-γ The thickness of the N layer, the non-doped Al b Ga 1-b The thickness of the N layer, the N-type Al δ Ga 1-δ The ratio of the thickness of the N layer is (6~10):(0.8~1.2):(6~11);

[0023] The N-type Al γ Ga 1-γ The doping concentration of the N layer is δ Ga 1-δ The doping concentration of the N layer is the same.

[0024] As an improvement of the above technical solution, the sum of the period number of the first multi-quantum well layer and the period number of the second multi-quantum well layer is 3-15, and the ratio of the period number of the first multi-quantum well layer to the period number of the second multi-quantum well layer is 1:(1-2).

[0025] As an improvement of the above technical solution, the number of periods of the second multi-quantum well layer is 2 to 10;

[0026] The thickness of the second quantum barrier layer is 5nm-30nm, the thickness of the second AlGaN layer, the thickness of the N-type Al γ Ga 1-γ The thickness of the N layer, the non-doped Al b Ga 1-b The thickness of the N layer, the N-type Al δ Ga 1-δThe ratio of the thickness of the N layer to the thickness of the third GaN layer is (0.6-1.2): (4-12): (0.8-1.2): (4-11): (0.6-1.3);

[0027] The Al component ratio in the second AlGaN layer is 0.05-0.35, and the N-type Al γ Ga 1-γ The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of γ is 0.05~0.2; the non-doped Al b Ga 1-b The value range of b in the N layer is 0.05~0.2; δ Ga 1-δ The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of δ is 0.05~0.2.

[0028] As an improvement of the above technical solution, it also includes a third multi-quantum well layer, wherein the third multi-quantum well layer is arranged between the first multi-quantum well layer and the P-type GaN layer, or the third multi-quantum well layer is arranged between the second multi-quantum well layer and the P-type GaN layer;

[0029] The third multi-quantum well layer includes quantum well layers and third quantum barrier layers that are alternately stacked, and the third quantum barrier layer includes a third AlGaN layer, a first Si-doped GaN layer, an undoped GaN layer, a second Si-doped GaN layer, and a fourth GaN layer that are sequentially stacked;

[0030] The proportion of Al component in the third AlGaN layer decreases from the side close to the quantum well layer to the side close to the first Si-doped GaN layer.

[0031] As an improvement of the above technical solution, the doping concentration of the first Si-doped GaN layer is greater than that of the N-type Al γ Ga 1-γ The doping concentration of the N layer is greater than that of the N-type Al δ Ga 1-δ Doping concentration of the N layer.

[0032] As an improvement of the above technical solution, the doping concentration of the first Si-doped GaN layer is the same as the doping concentration of the second Si-doped GaN layer;

[0033] The ratio of the thickness of the first Si-doped GaN layer, the thickness of the undoped GaN layer, and the thickness of the second Si-doped GaN layer is (6-10): (0.8-1.2): (6-11).

[0034] As an improvement of the above technical solution, the sum of the period number of the first multi-quantum well layer, the period number of the second multi-quantum well layer, and the period number of the third multi-quantum well layer is 3-15, and the ratio of the period number of the first multi-quantum well layer, the period number of the second multi-quantum well layer, and the period number of the third multi-quantum well layer is (1-1.2): (1-2): (0.8-1); or

[0035] The sum of the period number of the first multi-quantum well layer and the period number of the third multi-quantum well layer is 3-15, and the ratio of the period number of the first multi-quantum well layer to the period number of the third multi-quantum well layer is (1-1.2):(0.8-1).

[0036] As an improvement of the above technical solution, the number of periods of the third multi-quantum well layer is 2 to 10;

[0037] The thickness of the third quantum barrier layer is 5 nm to 30 nm, and the ratio of the thickness of the third AlGaN layer, the thickness of the first Si-doped GaN layer, the thickness of the undoped GaN layer, the thickness of the second Si-doped GaN layer and the thickness of the fourth GaN layer is (0.6-1.2): (4-12): (0.8-1.2): (4-11): (0.6-1.3);

[0038] The Al component ratio in the first AlGaN layer is 0.05-0.3, and the doping concentration of the first Si-doped GaN layer is 1×10 17 cm -3 ~1×10 18 cm -3 The doping concentration of the second Si-doped GaN layer is 1×10 17 cm -3 ~1×10 18 cm -3 .

[0039] Correspondingly, the present invention also discloses a method for preparing a Micro-LED epitaxial wafer, which is used to prepare the above-mentioned Micro-LED epitaxial wafer, and comprises:

[0040] Providing a substrate, and sequentially growing an N-type GaN layer, a first multi-quantum well layer, and a P-type GaN layer on the substrate, wherein the first multi-quantum well layer comprises quantum well layers and first quantum barrier layers that are alternately stacked;

[0041] The quantum well layer includes a first GaN layer, a first InGaN layer, and an Inx Ga 1-x The first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Al β Ga 1-β N layer and a second GaN layer;

[0042] The In component ratio of the first InGaN layer decreases from the side close to the first GaN layer to the side close to the In x Ga 1-x The N layer side changes gradually, and the maximum value of the In component ratio in the first InGaN layer is less than or equal to the In x Ga 1-x The proportion of In component in the N layer;

[0043] The Al component ratio in the first AlGaN layer decreases from the side close to the quantum well layer to the side close to the N-type Al α Ga 1-α The N-type AlGaN layer has a decreasing change, and the minimum value of the Al component ratio in the first AlGaN layer is greater than or equal to the N-type Al α Ga 1-α The proportion of Al component in the N layer.

[0044] As an improvement of the above technical solution, the In x Ga 1-x When the N layer grows, N source, Ga source, In source and carrier gas are first introduced, and grown at 700℃~900℃ and 50torr~300torr for 100s~200s, and then only N source, In source and carrier gas are introduced, and treated at 700℃~900℃ and 50torr~300torr for 10s~60s.

[0045] As an improvement of the above technical solution, the growth temperature of the quantum well layer is 700° C. to 900° C., and the growth pressure is 50 torr to 300 torr;

[0046] The growth temperature of the first quantum barrier layer is 800° C. to 950° C., and the growth pressure is 50 torr to 300 torr.

[0047] As an improvement of the above technical solution, the Micro-LED epitaxial wafer further includes a second multi-quantum well layer and a third multi-quantum well layer, the second multi-quantum well layer includes an alternately stacked quantum well layer and a second quantum barrier layer, and the third multi-quantum well layer includes an alternately stacked quantum well layer and a third quantum barrier layer;

[0048] The growth temperature of the quantum well layer is 700° C. to 900° C., and the growth pressure is 50 torr to 300 torr;

[0049] The growth temperature of the second quantum barrier layer is 800° C. to 950° C., and the growth pressure is 50 torr to 300 torr;

[0050] The growth temperature of the third quantum barrier layer is 800° C. to 950° C., and the growth pressure is 50 torr to 300 torr.

[0051] Correspondingly, the present invention also discloses a Micro-LED, which includes the above-mentioned Micro-LED epitaxial wafer.

[0052] The implementation of the present invention has the following beneficial effects:

[0053] 1. The Micro-LED epitaxial wafer in one embodiment of the present invention comprises a substrate, an N-type GaN layer, a first multi-quantum well layer and a P-type GaN layer in sequence. The first multi-quantum well layer comprises a quantum well layer and a first quantum barrier layer stacked in sequence; the quantum well layer comprises a first GaN layer, a first InGaN layer, an InGaN layer, a P-type Ga ... x Ga 1-x N layer and AlN layer; the In component ratio in the first InGaN layer decreases from the side close to the first GaN layer to the side close to the In x Ga 1-x The N layer side shows an increasing change, and the maximum value of its In component ratio is less than or equal to In x Ga 1-x The proportion of In in the N layer. Among them, the first GaN layer can be used as a preparation layer for subsequent layers to improve the crystal quality of subsequent layers. The first InGaN layer adopts a growth method with an increasing proportion of In, which greatly reduces the lattice mismatch with the first GaN layer and improves the In x Ga 1-x The crystal quality of the N layer also inhibits the increase in the density of screw dislocations and edge dislocations at the interface caused by the excessively high proportion of In. x Ga 1-x The N layer can play a role in stress compensation, which not only reduces the internal stress, but also prevents In atoms from being transported from the In-rich clusters to the N layer. x Ga 1-x The N layer diffuses to the terminal region, suppressing the degradation of In-rich clusters and the generation of non-radiative centers, improving the recombination efficiency of electrons and holes, and improving the luminous efficiency. The first quantum barrier layer includes the first AlGaN layer, the N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Alβ Ga 1-β N layer and the second GaN layer; the Al component ratio in the first AlGaN layer changes from the side close to the quantum well layer to the side close to the N-type Al α Ga 1-α The N layer side shows a decreasing change, and the minimum value of its Al component ratio is greater than or equal to N-type Al α Ga 1-α The proportion of Al components in the N layer. Among them, the proportion of Al components in the first AlGaN layer decreases, which can be used as a lattice buffer layer between the quantum well layer and the first quantum barrier layer to reduce lattice mismatch and improve the crystal quality of the first quantum barrier layer. α Ga 1-α N layer, non-doped Al a Ga 1-a N layer and N-type Al β Ga 1-β The N layer adopts the doped / undoped / doped growth method, which can not only shield the piezoelectric field caused by mismatch stress, alleviate the adverse effects of the quantum Stark effect (QCSE), and improve the radiation recombination efficiency, but also strengthen the localization effect and improve the electron mobility. The second GaN layer can be used as a connecting layer for the quantum well layer of the next cycle to improve the crystal quality of the quantum well layer of the next cycle.

[0054] 2. In the Micro-LED epitaxial wafer of one embodiment of the present invention, a second multi-quantum well layer is introduced between the first multi-quantum well layer and the P-type GaN layer. The second multi-quantum well layer includes quantum well layers and second quantum barrier layers that are alternately stacked. The second quantum barrier layer includes a second AlGaN layer, an N-type AlGaN layer, and a second AlGaN layer that are sequentially stacked. γ Ga 1-γ N layer, non-doped Al b Ga 1- b N layer, N-type Al δ Ga 1-δ N layer and the third GaN layer; the Al component ratio in the second AlGaN layer changes from the side close to the quantum well layer to the side close to the N-type Al γ Ga 1-γ The N layer side shows a decreasing change, and the minimum value of its Al component ratio is greater than or equal to N-type Al γ Ga 1-γ The proportion of Al components in the N layer; and γ≠α, b≠a, δ≠β. Among them, the proportion of Al components in the second AlGaN layer decreases, which can be used as a lattice buffer layer between the quantum well layer and the second quantum barrier layer to reduce lattice mismatch and improve the crystal quality of the second quantum barrier layer. N-type Al γ Ga 1-γ N layer, non-doped Al b Ga1-b N layer and N-type Al δ Ga 1-δ The N layer adopts a doped / undoped / doped growth method, which can not only shield the piezoelectric field caused by mismatch stress, alleviate the adverse effects of the quantum Stark effect (QCSE), and improve the radiation recombination efficiency, but also strengthen the localization effect and improve the electron mobility. The third GaN layer can be used as a connecting layer for the quantum well layer of the next cycle to improve the crystal quality of the quantum well layer of the next cycle. Furthermore, in one embodiment of the present invention, γ<α, b<a, δ<β are controlled. Based on this embodiment, the probability of hole injection into the quantum well layer close to the N-type GaN layer can be enhanced to improve the luminescence efficiency.

[0055] 3. In the Micro-LED light-emitting diode epitaxial wafer in one embodiment of the present invention, a third multi-quantum well layer is also introduced between the second multi-quantum well layer and the P-type GaN layer. The third multi-quantum well layer includes quantum well layers and third quantum barrier layers that are alternately stacked. Among them, the third quantum barrier layer includes a third AlGaN layer, a first Si-doped GaN layer, an undoped GaN layer, a second Si-doped GaN layer, and a fourth GaN layer that are stacked in sequence; the proportion of Al components in the third AlGaN layer decreases from the side close to the quantum well layer to the side close to the first Si-doped GaN layer. Among them, the third AlGaN layer can be used as a lattice buffer layer between the quantum well layer and the third quantum barrier layer to reduce lattice mismatch and improve the crystal quality of the third quantum barrier layer. The first Si-doped GaN layer, the undoped GaN layer, and the second Si-doped GaN layer adopt a doped / undoped / doped growth method, which can not only shield the piezoelectric field caused by mismatch stress, alleviate the adverse effects of the quantum Stark effect (QCSE), and improve the radiation recombination efficiency, but also strengthen the localization effect and improve the electron mobility. The fourth GaN layer can serve as a connection layer for the quantum well layer of the next period, improving the crystal quality of the quantum well layer of the next period. In addition, introducing less Al into the third quantum barrier layer of the P-type GaN layer can enhance the migration rate of holes to the quantum well layer close to the N-type GaN layer, thereby improving the luminous efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a schematic structural diagram of a Micro-LED epitaxial wafer in one embodiment of the present invention;

[0057] Figure 2 is a schematic structural diagram of a first multi-quantum well layer in one embodiment of the present invention;

[0058] Figure 3 is a schematic structural diagram of a Micro-LED epitaxial wafer in another embodiment of the present invention;

[0059] Figure 4is a schematic structural diagram of a Micro-LED epitaxial wafer in another embodiment of the present invention;

[0060] Figure 5 is a schematic structural diagram of a second multi-quantum well layer in one embodiment of the present invention;

[0061] Figure 6 is a schematic structural diagram of a Micro-LED epitaxial wafer in yet another embodiment of the present invention;

[0062] Figure 7 is a schematic structural diagram of a third multi-quantum well layer in one embodiment of the present invention;

[0063] Figure 8 It is a flow chart of a method for preparing a Micro-LED epitaxial wafer in one embodiment of the present invention.

[0064] 100 is a substrate, 200 is an N-type GaN layer, 300 is a first multi-quantum well layer, 310 is a quantum well layer, 311 is a first GaN layer, 312 is a first InGaN layer, 313 is an In x Ga 1-x N layer, 314 is an AlN layer, 320 is a first quantum barrier layer, 321 is a first AlGaN layer, and 322 is an N-type Al α Ga 1-α N layer, 323 is non-doped Al a Ga 1-a N layer, 324 is N-type Al β Ga 1-β N layer, 325 is the second GaN layer, 400 is the P-type GaN layer, 500 is the buffer layer, 600 is the intrinsic GaN layer, 700 is the electron blocking layer, 800 is the second multi-quantum well layer, 810 is the second quantum barrier layer, 811 is the second AlGaN layer, 812 is the N-type Al γ Ga 1-γ N layer, 813 is non-doped Al b Ga 1-b N layer, 814 is N-type Al δ Ga 1-δ N layer, 815 is a third GaN layer, 900 is a third multi-quantum well layer, 910 is a third quantum barrier layer, 911 is a third AlGaN layer, 912 is a first Si-doped GaN layer, 913 is an undoped GaN layer, 914 is a second Si-doped GaN layer, and 915 is a fourth GaN layer. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0066] See also Figure 1 and Figure 2 The present invention discloses a Micro-LED epitaxial wafer, which includes a substrate 100, an N-type GaN layer 200, a first multi-quantum well layer 300, and a P-type GaN layer 400 stacked in sequence on the substrate 100. The first multi-quantum well layer 300 includes a quantum well layer 310 and a first quantum barrier layer 320 stacked alternately; the quantum well layer 310 includes a first GaN layer 311, a first InGaN layer 312, an InGaN layer 313, and a P-type GaN layer 400 stacked in sequence. x Ga 1-x N layer 313 and AlN layer 314; the In component ratio of the first InGaN layer 312 decreases from the side close to the first GaN layer 311 to the side close to the In x Ga 1-x The N layer 313 side shows an increasing change, and the maximum value of its In component ratio is less than or equal to In x Ga 1-x The proportion of In in the N layer 313. Among them, the first GaN layer 311 can be used as a preparation layer for subsequent layers to improve the crystal quality of subsequent layers. The first InGaN layer 312 adopts a method of increasing the proportion of In, which greatly reduces the lattice mismatch with the first GaN layer 311 and improves the In x Ga 1-x The crystal quality of the N layer 313 also suppresses the increase in the density of screw dislocations and edge dislocations at the interface caused by the excessively high In component ratio. x Ga 1-x The N layer 313 can play a role in stress compensation, which not only reduces the internal stress, but also prevents In atoms from being transported from the In-rich clusters to the In-rich clusters. x Ga 1-x The N layer 313 diffuses toward the terminal region, suppressing the degradation of the In-rich clusters and the generation of non-radiative centers, improving the recombination efficiency of electrons and holes, and improving the luminous efficiency.

[0067] The first quantum barrier layer 320 includes a first AlGaN layer 321, an N-type Al α Ga 1-α N layer 322, non-doped Al a Ga 1-a N layer 323, N-type Al β Ga 1-β The proportion of Al in the first AlGaN layer 321 decreases from the side close to the quantum well layer 310 to the side close to the N-type Al α Ga 1-α The N layer 322 side shows a decreasing change, and the minimum value of its Al component ratio is greater than or equal to N-type Al α Ga 1-αThe Al component ratio in the N-type AlGaN layer 322 is gradually decreasing, and it can be used as a lattice buffer layer between the quantum well layer 310 and the first quantum barrier layer 320 to reduce the lattice mismatch and improve the crystal quality of the first quantum barrier layer 320. α Ga 1-α N layer 322, non-doped Al a Ga 1-a N-layer 323 and N-type Al β Ga 1-β The N layer 324 adopts a doped / undoped / doped growth method, which can not only shield the piezoelectric field caused by mismatch stress, alleviate the adverse effects of the quantum Stark effect (QCSE), and improve the radiation recombination efficiency, but also strengthen the localization effect and improve the electron mobility. The second GaN layer 325 can be used as a connection layer for the quantum well layer 310 of the next cycle to improve the crystal quality of the quantum well layer 310 of the next cycle.

[0068] Specifically, the number of periods of the first multi-quantum well layer 300 is 2-12, exemplarily 3, 5, 7 or 11, but not limited thereto, and preferably 2-10.

[0069] Specifically, the thickness of the first GaN layer 311 is 0.3 nm to 5 nm, exemplarily 0.4 nm, 1 nm, 1.5 nm, 3 nm, 4 nm or 4.8 nm, but not limited thereto, preferably 0.5 nm to 5 nm.

[0070] Specifically, the thickness of the first InGaN layer 312 is 0.1 nm to 1.5 nm, exemplarily 0.2 nm, 0.5 nm, 0.8 nm or 1.2 nm, but not limited thereto, preferably 0.1 nm to 1.0 nm.

[0071] Specifically, the In component ratio in the first InGaN layer 312 is 0.01-0.3. It should be noted that the In component ratio here refers to the average ratio of the In component in the entire first InGaN layer 312. The In component ratio in the first InGaN layer 312 increases along the growth direction of the Micro-LED epitaxial wafer. Specifically, it can increase linearly from 0.01-0.08 to In x Ga 1-x The In component ratio in the N layer 313 is, but not limited to, .

[0072] Specifically, in x Ga 1-x The thickness of the N layer 313 is 1 nm to 5 nm, exemplarily 1.2 nm, 2.4 nm, 3.3 nm or 4.5 nm, but not limited thereto, preferably 1 nm to 4 nm.

[0073] Specifically, in x Ga 1-x The In component ratio (ie, x) in the N layer 313 is 0.1-0.35, exemplarily 0.12, 0.15, 0.2, 0.23 or 0.25, but not limited thereto, and preferably 0.1-0.3.

[0074] Specifically, the thickness of the AlN layer 314 is 0.3 nm to 5 nm, exemplarily 0.5 nm, 1 nm, 3 nm, 4 nm or 4.5 nm, but not limited thereto, preferably 0.5 nm to 5 nm.

[0075] Preferably, in one embodiment, In x Ga 1-x The thickness of the N layer 313 is ≤3.5nm, and the value range of x is 0.1~0.3. By controlling the thickness and the proportion of In, the In x Ga 1-x The thickness of the N layer 313 is less than the de Broglie wavelength of electrons. The energy levels of electrons and holes are discrete quantized energy levels, which have a significant quantum confinement effect. In addition, its In-rich region produces a potential energy valley, and the In-rich region becomes a potential well for carriers. When electrons and holes are injected, they are easily captured by these potential wells and recombine to emit light, which greatly reduces the probability of non-radiative recombination caused by dislocation capture and improves the luminescence efficiency of the light-emitting diode.

[0076] Specifically, the thickness of the first quantum barrier layer 320 is 5 nm to 35 nm, and is exemplarily 8 nm, 12 nm, 20 nm, 25 nm, 30 nm or 34 nm, but is not limited thereto, and is preferably 5 nm to 30 nm.

[0077] Specifically, in the first quantum barrier layer 320, the thickness of the first AlGaN layer 321, the N-type Al α Ga 1-α The thickness of the N layer 322 and the non-doped Al a Ga 1-a The thickness of the N layer 323, the N-type Al β Ga 1-β The ratio of the thickness of the N layer 324 to the thickness of the second GaN layer 325 is (0.6-1.5): (4-15): (0.5-1.5): (4-14): (0.6-1.5), and is exemplarily 0.7:5:1:6:1, 1:4:1:6:1, 1:5:1:7:1 or 1:10:1:10:1, but is not limited thereto. Preferably, it is (0.6-1.2): (4-12): (0.8-1.2): (4-11): (0.6-1.3).

[0078] Specifically, the Al component ratio in the first AlGaN layer 321 is 0.05-0.5, preferably 0.05-0.4. It should be noted that the Al component ratio here refers to the average Al component ratio in the entire first AlGaN layer 321. The Al component ratio in the first AlGaN layer 321 decreases along the growth direction of the Micro-LED epitaxial wafer. Specifically, it can decrease linearly from 0.3-0.5 to N-type Al α Ga 1-α The Al component ratio in the N layer 322 .

[0079] Specifically, N-type Al α Ga 1-α The doping concentration of the N layer 322 is 1×10 17 cm -3 ~3×10 18 cm -3 , exemplarily 3×10 17 cm -3 ,7×10 17 cm -3 ,9×10 17 cm -3 or 2×10 18 cm -3 , but not limited thereto. Preferably 1×10 17 cm -3 ~1×10 18 cm -3 .

[0080] Specifically, N-type Al α Ga 1-α The Al component ratio (ie, α) in the N layer 322 is 0.05-0.4, exemplarily 0.08, 0.12, 0.2, 0.25 or 0.36, but not limited thereto, and preferably 0.05-0.3.

[0081] Specifically, non-doped Al a Ga 1-a The Al component ratio (ie, a) in the N layer 323 is 0.05-0.4, exemplarily 0.08, 0.12, 0.2, 0.25 or 0.36, but not limited thereto, and preferably 0.05-0.3.

[0082] Specifically, N-type Al β Ga 1-β The doping concentration of the N layer 324 is 1×10 17 cm -3 ~3×10 18 cm -3 , exemplarily 3×10 17 cm -3 ,7×1017 cm -3 ,9×10 17 cm -3 or 2×10 18 cm -3 , but not limited thereto. Preferably 1×10 17 cm -3 ~1×10 18 cm -3 .

[0083] Specifically, N-type Al β Ga 1-β The Al component ratio (ie, β) in the N layer 324 is 0.05-0.4, exemplarily 0.08, 0.12, 0.2, 0.25 or 0.36, but not limited thereto, and preferably 0.05-0.3.

[0084] Preferably, in one embodiment, N-type Al α Ga 1-α The Al component ratio in the N layer 322 and the non-doped Al a Ga 1-a Al component ratio in N layer 323, N-type Al β Ga 1-β The Al component ratio in the N layer 324 is the same, that is, α=a=β. By controlling the Al component ratio to be the same, it is possible to prevent the introduction of new stress, further improve the crystal quality of the first multi-quantum well layer 300, and improve the luminous efficiency.

[0085] Preferably, in one embodiment, N-type Al α Ga 1-α The doping concentration of the N layer 322 is related to the N-type Al β Ga 1-β The doping concentration of the N layer 324 is the same. Based on this doping concentration, the shielding effect on the piezoelectric field is stronger, which is beneficial to further enhance the recombination degree of electron and hole wave functions and improve the luminous efficiency.

[0086] Preferably, in one embodiment, N-type Al α Ga 1-α The thickness of the N layer 322 is related to the β Ga 1-β The thickness of the N layer 324 is the same. When the thickness is controlled in this way, the shielding effect on the piezoelectric field is stronger.

[0087] More preferably, in one embodiment, N-type Al α Ga 1-α The thickness of the N layer 322 and the non-doped Al a Ga 1-a The thickness of the N layer 323 and the N-type Al βGa 1-β The thickness ratio of the N layer 324 is (6-10): (0.8-1.2): (6-11); based on this thickness ratio, it not only further shields the piezoelectric field, but also enhances the confinement effect on carriers, thereby improving the luminous efficiency.

[0088] Specifically, the substrate 100 may be a sapphire substrate, a silicon substrate or a gallium oxide substrate, but is not limited thereto. A sapphire substrate is preferred.

[0089] Specifically, the doping element of the N-type GaN layer 200 is Si, but not limited thereto. The doping concentration of Si in the N-type GaN layer 200 is 5×10 18 cm -3 ~5×10 19 cm -3 , and its thickness is 1μm~3μm.

[0090] Specifically, the doping element of the P-type GaN layer 400 is Mg, but not limited thereto. The thickness of the P-type GaN layer 400 is 50 nm to 200 nm, and the Mg doping concentration is 1×10 19 cm -3 ~5×10 20 cm -3 .

[0091] Preferably, see Figure 3 In one embodiment, the micro-LED epitaxial wafer further includes a buffer layer 500, an intrinsic GaN layer 600 and an electron blocking layer 700; wherein the buffer layer 500 and the intrinsic GaN layer 600 are sequentially stacked between the substrate 100 and the N-type GaN layer 200. The electron blocking layer 700 is disposed between the first multi-quantum well layer 300 and the P-type GaN layer 400.

[0092] Specifically, the buffer layer 500 is an AlN layer or an AlGaN layer, but is not limited thereto. The buffer layer 500 has a thickness of 10 nm to 50 nm.

[0093] Specifically, the thickness of the intrinsic GaN layer 600 is 1 μm to 5 μm.

[0094] Specifically, the electron blocking layer 700 is an AlGaN layer or an AlInGaN layer, but is not limited thereto. Preferably, in one embodiment, the electron blocking layer 700 is an AlInGaN layer, wherein the Al component accounts for 0.01-0.05, the In component accounts for 0.01-0.05, and the thickness is 10nm-40nm.

[0095] Preferably, in one embodiment, the Micro-LED epitaxial wafer further includes a second multi-quantum well layer 800, which is disposed between the first multi-quantum well layer 300 and the P-type GaN layer 400, or between the first multi-quantum well layer 300 and the electron blocking layer 700. More preferably, see Figure 4 The second multi-quantum well layer 800 is disposed between the first multi-quantum well layer 300 and the electron blocking layer 700. The second multi-quantum well layer 800 includes quantum well layers 310 and second quantum barrier layers 810 that are alternately stacked. Figure 5 The second quantum barrier layer 810 includes a second AlGaN layer 811, an N-type Al γ Ga 1-γ N layer 812, non-doped Al b Ga 1-b N layer 813, N-type Al δ Ga 1-δ N layer 814 and the third GaN layer 815; the Al component ratio in the second AlGaN layer 811 is from the side close to the quantum well layer 310 to the side close to the N-type Al γ Ga 1-γ The N layer 812 side shows a decreasing change, and the minimum value of its Al component ratio is greater than or equal to N-type Al γ Ga 1-γ The Al component ratio in the N-layer 812 is γ≠α, b≠a, and δ≠β. The Al component ratio in the second AlGaN layer 811 decreases gradually, and it can be used as a lattice buffer layer between the quantum well layer 310 and the second quantum barrier layer 810 to reduce the lattice mismatch and improve the crystal quality of the second quantum barrier layer 810. N-type Al γ Ga 1-γ N layer 812, non-doped Al b Ga 1-b N layer 813 and N-type Al δ Ga 1-δ The N layer 814 adopts a doped / undoped / doped growth method, which can not only shield the piezoelectric field caused by mismatch stress, alleviate the adverse effects of the quantum Stark effect (QCSE), and improve the radiation recombination efficiency, but also strengthen the localization effect and improve the electron mobility. The third GaN layer 815 can be used as a connection layer for the quantum well layer 310 of the next cycle to improve the crystal quality of the quantum well layer 310 of the next cycle.

[0096] Specifically, the period number of the second multi-quantum well layer 800 is 2 to 12, and is exemplarily 3, 5, 7 or 11, but is not limited thereto. Preferably, it is 2 to 10. Preferably, based on this embodiment, the sum of the period number of the first multi-quantum well layer 300 and the period number of the second multi-quantum well layer 800 is 3 to 15, and the ratio of the period number of the first multi-quantum well layer 300 to the period number of the second multi-quantum well layer 800 is 1:(1 to 2).

[0097] Specifically, the thickness of the second quantum barrier layer 810 is 5 nm to 35 nm, and is exemplarily 8 nm, 12 nm, 20 nm, 25 nm, 30 nm or 34 nm, but is not limited thereto, and is preferably 5 nm to 30 nm.

[0098] Specifically, in the second quantum barrier layer 810, the thickness of the second AlGaN layer 811, the N-type Al γ Ga 1-γ The thickness of the N layer 812 and the non-doped Al b Ga 1-b The thickness of the N layer 813, the N-type Al δ Ga 1-δ The ratio of the thickness of the N layer 814 to the thickness of the third GaN layer 815 is (0.6-1.5): (4-15): (0.5-1.5): (4-14): (0.6-1.5), and is exemplarily 0.7:5:1:6:1, 1:4:1:6:1, 1:5:1:7:1 or 1:10:1:10:1, but is not limited thereto. Preferably, it is (0.6-1.2): (4-12): (0.8-1.2): (4-11): (0.6-1.3).

[0099] Specifically, the Al component ratio in the second AlGaN layer 811 is 0.05-0.4, preferably 0.05-0.35. It should be noted that the Al component ratio here refers to the average Al component ratio in the entire second AlGaN layer 811. The Al component ratio in the second AlGaN layer 811 decreases along the growth direction of the Micro-LED epitaxial wafer. Specifically, it can decrease linearly from 0.25-0.4 to N-type AlGaN. γ Ga 1-γ The Al component ratio in the N layer 812.

[0100] Specifically, N-type Al γ Ga 1-γ The doping concentration of the N layer 812 is 1×10 17 cm -3 ~4×10 18 cm -3 , exemplarily 3×10 17 cm -3 ,7×1017 cm -3 ,9×10 17 cm -3 , 2×10 18 cm -3 or 3×10 18 cm -3 , but not limited thereto. Preferably 1×10 17 cm -3 ~1×10 18 cm -3 .

[0101] Specifically, N-type Al γ Ga 1-γ The Al component ratio (ie, γ) in the N layer 812 is 0.05-0.35, exemplarily 0.08, 0.12, 0.2, 0.25 or 0.34, but not limited thereto, preferably 0.05-0.2.

[0102] Specifically, non-doped Al b Ga 1-b The Al component ratio (i.e., b) in the N layer 813 is 0.05-0.35, and is exemplarily 0.08, 0.12, 0.2, 0.25, or 0.34, but is not limited thereto. Preferably, it is 0.05-0.2.

[0103] Specifically, N-type Al δ Ga 1-δ The doping concentration of the N layer 814 is 1×10 17 cm -3 ~4×10 18 cm -3 , exemplarily 3×10 17 cm -3 ,7×10 17 cm -3 ,9×10 17 cm -3 , 2×10 18 cm -3 or 3×10 18 cm -3 , but not limited thereto. Preferably 1×10 17 cm -3 ~1×10 18 cm -3 .

[0104] Specifically, N-type Al δ Ga 1-δ The Al component ratio (ie, δ) in the N layer 814 is 0.05-0.35, exemplarily 0.08, 0.12, 0.2, 0.25 or 0.34, but not limited thereto, preferably 0.05-0.2.

[0105] Preferably, in one embodiment, the proportion of Al component in the second AlGaN layer 811 is less than that in the first AlGaN layer 321, γ<α, b<a, δ<β. Based on this embodiment, the probability of hole injection into the quantum well layer 310 close to the N-type GaN layer 200 can be enhanced, thereby improving the luminous efficiency.

[0106] Preferably, in one embodiment, N-type Al γ Ga 1-γ The doping concentration of the N layer 812 is greater than that of the N-type Al α Ga 1-α The doping concentration of the N layer 322; N-type Al δ Ga 1-δ The doping concentration of the N layer 814 is greater than that of the N-type Al β Ga 1-β The doping concentration of the N layer 324. Based on this embodiment, the shielding effect on the piezoelectric field can be improved.

[0107] Preferably, in one embodiment, N-type Al γ Ga 1-γ The Al component ratio in the N layer 812 and the non-doped Al b Ga 1-b Al component ratio in N layer 813, N-type Al δ Ga 1-δ The proportion of Al components in the N layer 814 is the same, that is, γ=b=δ. By controlling the proportion of Al components to be the same, it is possible to prevent the introduction of new stress, further improve the crystal quality of the second multi-quantum well layer 800, and improve the luminous efficiency.

[0108] Preferably, in one embodiment, N-type Al γ Ga 1-γ The doping concentration of the N layer 812 is related to the N-type Al δ Ga 1-δ The doping concentration of the N layer 814 is the same. Based on this doping concentration, the shielding effect on the piezoelectric field is stronger, which is conducive to further enhancing the recombination degree of electron and hole wave functions and improving the luminous efficiency.

[0109] Preferably, in one embodiment, N-type Al γ Ga 1-γ The thickness of the N layer 812 is related to the N-type Al δ Ga 1-δ The thickness of the N layer 814 is the same. When the thickness is controlled in this way, the shielding effect on the piezoelectric field is stronger.

[0110] More preferably, in one embodiment, N-type Al γ Ga 1-γThe thickness of the N layer 812 and the non-doped Al b Ga 1-b The thickness of the N layer 813, the N-type Al δ Ga 1-δ The thickness ratio of the N layer 814 is (6~10): (0.8~1.2): (6~11); based on this thickness ratio, it not only further shields the piezoelectric field, but also enhances the confinement effect on carriers and improves the luminous efficiency.

[0111] Preferably, in one embodiment, the Micro-LED epitaxial wafer further includes a third multi-quantum well layer 900, which is disposed between the first multi-quantum well layer 300 and the P-type GaN layer 400, or between the second multi-quantum well layer 800 and the P-type GaN layer 400, or between the first multi-quantum well layer 300 and the electron blocking layer 700, or between the second multi-quantum well layer 800 and the electron blocking layer 700. More preferably, see Figure 6 The third multi-quantum well layer 900 is disposed between the second multi-quantum well layer 800 and the electron blocking layer 700. The third multi-quantum well layer 900 includes quantum well layers 310 and third quantum barrier layers 910 that are alternately stacked. Figure 7 The third quantum barrier layer 910 includes a third AlGaN layer 911, a first Si-doped GaN layer 912, an undoped GaN layer 913, a second Si-doped GaN layer 914, and a fourth GaN layer 915 stacked in sequence; the proportion of Al components in the third AlGaN layer 911 decreases from the side close to the quantum well layer 310 to the side close to the first Si-doped GaN layer 912. Among them, the third AlGaN layer 911 can be used as a lattice buffer layer between the quantum well layer 310 and the third quantum barrier layer 910 to reduce the lattice mismatch and improve the crystal quality of the third quantum barrier layer 910. The first Si-doped GaN layer 912, the undoped GaN layer 913, and the second Si-doped GaN layer 914 adopt a doped / undoped / doped growth method, which can not only shield the piezoelectric field caused by mismatch stress, alleviate the adverse effects of the quantum Stark effect (QCSE), and improve the radiation recombination efficiency, but also strengthen the localization effect and improve the electron mobility. The fourth GaN layer 915 can be used as a connection layer for the next period of quantum well layer 310, thereby improving the crystal quality of the next period of quantum well layer 310. In addition, introducing less Al into the third quantum barrier layer 910 of the P-type GaN layer 400 can enhance the migration rate of holes to the quantum well layer 310 close to the N-type GaN layer 200, thereby improving the luminous efficiency.

[0112] Specifically, the period number of the third multi-quantum well layer 900 is 2 to 12, exemplarily 3, 5, 7 or 11, but not limited thereto. Preferably, it is 2 to 10. Preferably, based on this embodiment, the sum of the period number of the first multi-quantum well layer 300, the period number of the second multi-quantum well layer 800, and the period number of the third multi-quantum well layer 900 is 3 to 15, and the ratio of the period number of the first multi-quantum well layer 300, the period number of the second multi-quantum well layer 800, and the period number of the third multi-quantum well layer 900 is (1 to 1.2): (1 to 2): (0.8 to 1); or the sum of the period number of the first multi-quantum well layer 300 and the period number of the third multi-quantum well layer 900 is 3 to 15, and the ratio of the period number of the first multi-quantum well layer 300 to the period number of the third multi-quantum well layer 900 is (1 to 1.2): (0.8 to 1).

[0113] Specifically, the thickness of the third quantum barrier layer 910 is 5 nm to 35 nm, and is exemplarily 8 nm, 12 nm, 20 nm, 25 nm, 30 nm or 34 nm, but is not limited thereto, and is preferably 5 nm to 30 nm.

[0114] Specifically, in the third quantum barrier layer 910, the thickness of the third AlGaN layer 911, the thickness of the first Si-doped GaN layer 912, the thickness of the non-doped GaN layer 913, the thickness of the second Si-doped GaN layer 914 and the thickness of the fourth GaN layer 915 are in the ratio of (0.6-1.5): (4-15): (0.5-1.5): (4-14): (0.6-1.5), exemplarily 0.7:5:1:6:1, 1:4:1:6:1, 1:5:1:7:1 or 1:10:1:10:1, but not limited thereto. Preferably, it is (0.6-1.2): (4-12): (0.8-1.2): (4-11): (0.6-1.3).

[0115] Specifically, the Al component ratio in the third AlGaN layer 911 is 0.05-0.35, preferably 0.05-0.3. It should be noted that the Al component ratio here refers to the average ratio. The Al component ratio in the third AlGaN layer 911 decreases, specifically, it can decrease linearly from 0.1-0.3 to 0.02-0.05.

[0116] Specifically, the doping concentration of the first Si-doped GaN layer 912 is 1×10 17 cm -3 ~5×10 18 cm -3 , exemplarily 3×10 17 cm -3 ,7×10 17 cm -3 ,9×10 17 cm-3 , 2×10 18 cm -3 or 4×10 18 cm -3 , but not limited thereto. Preferably 1×10 17 cm -3 ~1×10 18 cm -3 .

[0117] Specifically, the doping concentration of the second Si-doped GaN layer 914 is 1×10 17 cm -3 ~5×10 18 cm -3 , exemplarily 3×10 17 cm -3 ,7×10 17 cm -3 ,9×10 17 cm -3 , 2×10 18 cm -3 or 4×10 18 cm -3 , but not limited thereto. Preferably 1×10 17 cm -3 ~1×10 18 cm -3 .

[0118] Preferably, in one embodiment, the doping concentration of the first Si-doped GaN layer 912 is greater than that of the N-type Al γ Ga 1-γ The doping concentration of the N layer 812 and the second Si-doped GaN layer 914 is greater than that of the N-type Al δ Ga 1-δ The doping concentration of the N layer 814. Based on this embodiment, firstly, the shielding effect on the piezoelectric field can be further improved. Secondly, the mobility of electrons can be improved, the localization effect can be improved, the recombination of electrons and holes can be promoted, and the luminous efficiency can be improved.

[0119] Preferably, in one embodiment, the proportion of Al component in the third AlGaN layer 911 is less than the proportion of Al component in the second AlGaN layer 811. Based on this embodiment, the blocking of holes can be further reduced and the light emitting efficiency can be improved.

[0120] Preferably, in one embodiment, the doping concentration of the first Si-doped GaN layer 912 is the same as the doping concentration of the second Si-doped GaN layer 914. At this doping concentration, the shielding effect on the piezoelectric field is stronger, which is conducive to further enhancing the recombination degree of electron and hole wave functions and improving the luminous efficiency.

[0121] Preferably, in one embodiment, the thickness of the first Si-doped GaN layer 912 is the same as the thickness of the second Si-doped GaN layer 914. When the thickness is controlled in this way, the shielding effect on the piezoelectric field is stronger.

[0122] More preferably, in one embodiment, the ratio of the thickness of the first Si-doped GaN layer 912, the thickness of the undoped GaN layer 913 and the thickness of the second Si-doped GaN layer 914 is (6~10):(0.8~1.2):(6~11); based on this thickness ratio, not only the piezoelectric field is further shielded, but also the confinement effect on carriers can be enhanced, thereby improving the luminous efficiency.

[0123] Accordingly, see Figure 8 The present invention also provides a method for preparing a Micro-LED epitaxial wafer, which is used to prepare the above-mentioned Micro-LED epitaxial wafer, and specifically comprises the following steps:

[0124] S1: providing a substrate;

[0125] S2: sequentially growing an N-type GaN layer, a first multi-quantum well layer and a P-type GaN layer on the substrate;

[0126] Specifically, in some embodiments of the present invention, step S2 includes:

[0127] S21: growing a buffer layer on the substrate;

[0128] Specifically, in one embodiment of the present invention, an AlN layer is grown by PVD as a buffer layer.

[0129] S22: growing an intrinsic non-doped GaN layer on the buffer layer;

[0130] Specifically, in one embodiment of the present invention, the intrinsic GaN layer is grown by MOCVD, the growth temperature is 1000° C. to 1200° C., and the growth pressure is 100 torr to 500 torr.

[0131] S23: growing an N-type GaN layer on the intrinsic GaN layer;

[0132] Specifically, in one embodiment of the present invention, an N-type GaN layer is grown by MOCVD, and the growth temperature is 1100° C. to 1200° C. and the growth pressure is 100 torr to 500 torr.

[0133] S24: growing a first multi-quantum well layer on the N-type GaN layer;

[0134] Specifically, in one embodiment, a quantum well layer and a first quantum barrier layer are periodically grown on the N-type GaN layer by MOCVD until a first multi-quantum well layer is obtained.

[0135] The growth temperature of the quantum well layer is 700°C~900°C, and the growth pressure is 50torr~300torr; the growth temperature of the first quantum barrier layer is 800°C~950°C, and the growth pressure is 50torr~300torr.

[0136] Preferably, in one embodiment, In x Ga 1-x When the N layer grows, first introduce N source, Ga source, In source and carrier gas, grow at 700℃~900℃, 50torr~300torr for 100s~200s, then introduce only N source, In source and carrier gas, and process at 700℃~900℃, 50torr~300torr for 10s~60s. Based on this growth method, In volatilization can be effectively suppressed, In uniformity can be improved, and the piezoelectric field intensity can be reduced, thereby improving the luminous efficiency.

[0137] S25: growing a second multi-quantum well layer on the first multi-quantum well layer;

[0138] Specifically, in one embodiment, a quantum well layer and a second quantum barrier layer are periodically grown on the first multi-quantum well layer by MOCVD until the second multi-quantum well layer is obtained.

[0139] The growth temperature of the quantum well layer is 700°C~900°C, and the growth pressure is 50torr~300torr; the growth temperature of the second quantum barrier layer is 800°C~950°C, and the growth pressure is 50torr~300torr.

[0140] S26: growing a third multi-quantum well layer on the second multi-quantum well layer;

[0141] Specifically, in one embodiment, a quantum well layer and a third quantum barrier layer are periodically grown on the second multi-quantum well layer by MOCVD until a third multi-quantum well layer is obtained.

[0142] Among them, the growth temperature of the quantum well layer is 700℃~900℃, and the growth pressure is 50torr~300torr; the growth temperature of the third quantum barrier layer is 800℃~950℃, and the growth pressure is 50torr~300torr.

[0143] S27: growing an electron blocking layer on the third multi-quantum well layer;

[0144] Specifically, in one embodiment, an AlInGaN layer is grown by MOCVD as an electron blocking layer, and the growth temperature is 900° C. to 1000° C. and the growth pressure is 100 torr to 300 torr.

[0145] S28: growing a P-type GaN layer on the electron blocking layer;

[0146] Specifically, in one embodiment, the P-type GaN layer is grown by MOCVD, the growth temperature is 900° C. to 1050° C., and the growth pressure is 100 torr to 500 torr.

[0147] The present invention will be further described below with specific embodiments:

[0148] Example 1

[0149] The present embodiment provides a Micro-LED epitaxial wafer, which includes a substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a first multi-quantum well layer, an electron blocking layer and a P-type GaN layer stacked in sequence on the substrate.

[0150] The substrate is a sapphire substrate, the buffer layer is an AlN layer with a thickness of 30 nm, and the thickness of the intrinsic GaN layer is 2.5 μm. The Si doping concentration in the N-type GaN layer is 3×10 19 cm -3 , with a thickness of 2μm. The electron blocking layer is an AlInGaN layer, with an In component ratio of 0.03, an Al component ratio of 0.02, and a thickness of 20nm. The Mg doping concentration in the P-type GaN layer is 2.5×10 20 cm -3 , and its thickness is 150nm.

[0151] The first multi-quantum well layer includes quantum well layers and first quantum barrier layers that are alternately stacked, and the number of cycles is 10. Each quantum well layer includes a first GaN layer, a first InGaN layer, and an InGaN layer that are sequentially stacked. x Ga 1-x N layer (x=0.32) and AlN layer, wherein the thickness of the first GaN layer is 1.2nm, the thickness of the first InGaN layer is 0.3nm, and the In composition thereof increases linearly from 0.05 to 0.32; In x Ga 1-x The thickness of the N layer is 3.8 nm, and the thickness of the AlN layer is 1.8 nm. Each first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1-α N layer (α=0.3), non-doped Al a Ga 1-a N layer (a=0.25), N-type Al β Ga 1-β N layer (β = 0.2) and the second GaN layer; the thickness of the first quantum barrier layer is 15nm, the first AlGaN layer, N-type Al α Ga 1-α N layer, non-doped Ala Ga 1-a N layer, N-type Al β Ga 1-β The thickness ratio of the N layer to the second GaN layer is 1:4:1:5:1. The Al content in the first AlGaN layer decreases linearly from 0.3 to 0.25. α Ga 1-α The Si doping concentration in the N layer is 2.5×10 17 cm -3 , N-type Al β Ga 1-β The Si doping concentration in the N layer is 3.1×10 17 cm -3 .

[0152] The method for preparing the Micro-LED epitaxial wafer in this embodiment includes the following steps:

[0153] (1) Providing a substrate;

[0154] (2) growing a buffer layer on the substrate;

[0155] Specifically, an AlN layer is grown by PVD as a buffer layer.

[0156] (3) growing an intrinsic GaN layer on the buffer layer;

[0157] Specifically, the non-doped GaN layer is grown by MOCVD at a growth temperature of 1050° C. and a growth pressure of 300 torr.

[0158] (4) Growing an N-type GaN layer on the intrinsic GaN layer;

[0159] Specifically, the N-type GaN layer is grown by MOCVD at a growth temperature of 1120° C. and a growth pressure of 300 torr.

[0160] (5) growing a first multi-quantum well layer on the N-type GaN layer;

[0161] Specifically, quantum well layers and first quantum barrier layers are alternately grown on the N-type GaN layer by MOCVD until a first multi-quantum well layer is obtained, wherein the growth temperature of the quantum well layer is 780°C and the growth pressure is 200 torr; the growth temperature of the first quantum barrier layer is 940°C and the growth pressure is 200 torr.

[0162] In addition, x Ga 1-x The N layer is grown by introducing N source (NH3), Ga source (TEGa), In source (TMIn) and carrier gas (N2) at 780°C and 200 torr for 150 seconds.

[0163] (6) growing an electron blocking layer on the first multi-quantum well layer;

[0164] Specifically, an AlInGaN layer was grown by MOCVD as an electron blocking layer at a growth temperature of 930° C. and a growth pressure of 300 torr.

[0165] (7) Growing a P-type GaN layer on the electron blocking layer;

[0166] Specifically, the P-type GaN layer is grown by MOCVD at a growth temperature of 980° C. and a growth pressure of 400 torr.

[0167] Example 2

[0168] This embodiment provides a Micro-LED epitaxial wafer, which is different from the embodiment 1 in that:

[0169] The In content in the first InGaN layer increases linearly from 0.05 to 0.15; x Ga 1-x The thickness of the N layer is 3.2nm, x=0.15.

[0170] The rest are the same as in Example 1.

[0171] Example 3

[0172] This embodiment provides a Micro-LED epitaxial wafer, which is different from Embodiment 2 in that:

[0173] The Al composition in the first AlGaN layer decreases linearly from 0.3 to 0.1, α=a=β=0.1;

[0174] The first AlGaN layer, N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Al β Ga 1-β The thickness ratio of the N layer to the second GaN layer is 1:6:1:6:1.

[0175] The rest is the same as Example 2.

[0176] Example 4

[0177] This embodiment provides a Micro-LED epitaxial wafer, which is different from the embodiment 3 in that:

[0178] N-type Al α Ga 1-α The Si doping concentration in the N layer and the N-type Al β Ga 1-βThe Si doping concentration in the N layer is the same, both 2.5×10 17 cm -3 .

[0179] The rest is the same as Example 3.

[0180] Example 5

[0181] This embodiment provides a Micro-LED epitaxial wafer, which is different from the embodiment 4 in that:

[0182] In addition, x Ga 1-x The growth method of the N layer is as follows: first, N source (NH3), Ga source (TEGa), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 150 seconds. Then, only N source (NH3), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 15 seconds.

[0183] The rest is the same as Example 4.

[0184] Example 6

[0185] The present embodiment provides a Micro-LED epitaxial wafer, which includes a substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a first multi-quantum well layer, a second multi-quantum well layer, an electron blocking layer and a P-type GaN layer stacked in sequence on the substrate.

[0186] The substrate is a sapphire substrate, the buffer layer is an AlN layer with a thickness of 30 nm, and the thickness of the intrinsic GaN layer is 2.5 μm. The Si doping concentration in the N-type GaN layer is 3×10 19 cm -3 , with a thickness of 2μm. The electron blocking layer is an AlInGaN layer, with an In component ratio of 0.03, an Al component ratio of 0.02, and a thickness of 20nm. The Mg doping concentration in the P-type GaN layer is 2.5×10 20 cm -3 , and its thickness is 150nm.

[0187] The first multi-quantum well layer includes quantum well layers and first quantum barrier layers that are alternately stacked, and the number of cycles is 4. Each quantum well layer includes a first GaN layer, a first InGaN layer, an InGaN layer, and a x Ga 1-x N layer (x=0.15) and AlN layer, wherein the thickness of the first GaN layer is 1.2nm, the thickness of the first InGaN layer is 0.3nm, and the In composition thereof increases linearly from 0.05 to 0.15; In x Ga 1-xThe thickness of the N layer is 3.2nm, and the thickness of the AlN layer is 1.8nm. Each first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1-α N layer (α=0.1), non-doped Al a Ga 1-a N layer (a=0.1), N-type Al β Ga 1-β N layer (β = 0.1) and the second GaN layer; the thickness of the first quantum barrier layer is 15nm, the first AlGaN layer, N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Al β Ga 1-β The thickness ratio of the N layer to the second GaN layer is 1:6:1:6:1. The Al content in the first AlGaN layer decreases linearly from 0.3 to 0.1. α Ga 1-α The Si doping concentration in the N layer is 2.5×10 17 cm -3 , N-type Al β Ga 1-β The Si doping concentration in the N layer is 2.5×10 17 cm -3 .

[0188] The second multi-quantum well layer includes quantum well layers and second quantum barrier layers that are alternately stacked, and the number of cycles is 6. Each quantum well layer includes a first GaN layer, a first InGaN layer, an InGaN layer, and a second GaN layer that are sequentially stacked. x Ga 1-x N layer (x=0.15) and AlN layer, wherein the thickness of the first GaN layer is 1.2nm, the thickness of the first InGaN layer is 0.3nm, and the In composition thereof increases linearly from 0.05 to 0.15; In x Ga 1-x The thickness of the N layer is 3.2nm, and the thickness of the AlN layer is 1.8nm. Each second quantum barrier layer includes a second AlGaN layer, an N-type Al γ Ga 1-γ N layer (γ=0.2), non-doped Al b Ga 1-b N layer (b=0.2), N-type Al δ Ga 1-δ N layer (δ = 0.2) and the third GaN layer, the second AlGaN layer, the N-type Al γ Ga 1-γ N layer, non-doped Al b Ga1-b N layer, N-type Al δ Ga 1-δ The thickness ratio of the N layer and the third GaN layer is 1:6:1:6:1. The Al content in the second AlGaN layer decreases linearly from 0.3 to 0.2. γ Ga 1-γ The Si doping concentration in the N layer is 2.5×10 17 cm -3 , N-type Al δ Ga 1-δ The Si doping concentration in the N layer is 3.5×10 17 cm -3 .

[0189] The method for preparing the Micro-LED epitaxial wafer in this embodiment includes the following steps:

[0190] (1) Providing a substrate;

[0191] (2) growing a buffer layer on the substrate;

[0192] Specifically, an AlN layer is grown by PVD as a buffer layer.

[0193] (3) growing an intrinsic GaN layer on the buffer layer;

[0194] Specifically, the non-doped GaN layer is grown by MOCVD at a growth temperature of 1050° C. and a growth pressure of 300 torr.

[0195] (4) Growing an N-type GaN layer on the intrinsic GaN layer;

[0196] Specifically, the N-type GaN layer is grown by MOCVD at a growth temperature of 1120° C. and a growth pressure of 300 torr.

[0197] (5) growing a first multi-quantum well layer on the N-type GaN layer;

[0198] Specifically, quantum well layers and first quantum barrier layers are alternately grown on the N-type GaN layer by MOCVD until a first multi-quantum well layer is obtained, wherein the growth temperature of the quantum well layer is 780°C and the growth pressure is 200 torr; the growth temperature of the first quantum barrier layer is 940°C and the growth pressure is 200 torr.

[0199] In addition, x Ga 1-xThe growth method of the N layer is as follows: first, N source (NH3), Ga source (TEGa), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 150 seconds. Then, only N source (NH3), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 15 seconds.

[0200] (6) growing a second multi-quantum well layer on the first multi-quantum well layer;

[0201] Specifically, quantum well layers and second quantum barrier layers are alternately grown on the first multi-quantum well layer by MOCVD until the second multi-quantum well layer is obtained, wherein the growth temperature of the quantum well layer is 780°C and the growth pressure is 200 torr; the growth temperature of the second quantum barrier layer is 920°C and the growth pressure is 200 torr.

[0202] In addition, x Ga 1-x The growth method of the N layer is as follows: first, N source (NH3), Ga source (TEGa), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 150 seconds. Then, only N source (NH3), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 15 seconds.

[0203] (7) growing an electron blocking layer on the second multi-quantum well layer;

[0204] Specifically, an AlInGaN layer was grown by MOCVD as an electron blocking layer at a growth temperature of 930° C. and a growth pressure of 300 torr.

[0205] (8) Growing a P-type GaN layer on the electron blocking layer;

[0206] Specifically, the P-type GaN layer is grown by MOCVD at a growth temperature of 980° C. and a growth pressure of 400 torr.

[0207] Example 7

[0208] This embodiment provides a Micro-LED epitaxial wafer, which is different from the embodiment 6 in that:

[0209] N-type Al γ Ga 1-γ The Si doping concentration in the N layer and the N-type Al δ Ga 1-δ The Si doping concentration in the N layer is the same, which is 5.5×10 17 cm -3 ;

[0210] The Al composition in the second AlGaN layer decreases linearly from 0.2 to 0.08, and γ=b=δ=0.08.

[0211] The rest are the same as in Example 6.

[0212] Example 8

[0213] The present embodiment provides a Micro-LED epitaxial wafer, which includes a substrate, a buffer layer, an intrinsic GaN layer, an N-type GaN layer, a first multi-quantum well layer, a second multi-quantum well layer, a third multi-quantum well layer, an electron blocking layer and a P-type GaN layer stacked in sequence on the substrate.

[0214] The substrate is a sapphire substrate, the buffer layer is an AlN layer with a thickness of 30 nm, and the thickness of the intrinsic GaN layer is 2.5 μm. The Si doping concentration in the N-type GaN layer is 3×10 19 cm -3 , with a thickness of 2μm. The electron blocking layer is an AlInGaN layer, with an In component ratio of 0.03, an Al component ratio of 0.02, and a thickness of 20nm. The Mg doping concentration in the P-type GaN layer is 2.5×10 20 cm -3 , and its thickness is 150nm.

[0215] The first multi-quantum well layer includes quantum well layers and first quantum barrier layers that are alternately stacked, and the number of cycles is 3. Each quantum well layer includes a first GaN layer, a first InGaN layer, and an InGaN layer that are sequentially stacked. x Ga 1-x N layer (x=0.15) and AlN layer, wherein the thickness of the first GaN layer is 1.2nm, the thickness of the first InGaN layer is 0.3nm, and the In composition thereof increases linearly from 0.05 to 0.15; In x Ga 1-x The thickness of the N layer is 3.2nm, and the thickness of the AlN layer is 1.8nm. Each first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1-α N layer (α=0.1), non-doped Al a Ga 1-a N layer (a=0.1), N-type Al β Ga 1-β N layer (β = 0.1) and the second GaN layer; the thickness of the first quantum barrier layer is 15nm, the first AlGaN layer, N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Al β Ga 1-βThe thickness ratio of the N layer to the second GaN layer is 1:6:1:6:1. The Al content in the first AlGaN layer decreases linearly from 0.3 to 0.1. α Ga 1-α The Si doping concentration in the N layer is 2.5×10 17 cm -3 , N-type Al β Ga 1-β The Si doping concentration in the N layer is 2.5×10 17 cm -3 .

[0216] The second multi-quantum well layer includes quantum well layers and second quantum barrier layers that are alternately stacked, and the number of cycles is 4. Each quantum well layer includes a first GaN layer, a first InGaN layer, an InGaN layer, and a second GaN layer that are sequentially stacked. x Ga 1-x N layer (x=0.15) and AlN layer, wherein the thickness of the first GaN layer is 1.2nm, the thickness of the first InGaN layer is 0.3nm, and the In composition thereof increases linearly from 0.05 to 0.15; In x Ga 1-x The thickness of the N layer is 3.2nm, and the thickness of the AlN layer is 1.8nm. Each first quantum barrier layer includes a second AlGaN layer, an N-type Al γ Ga 1-γ N layer (γ=0.08), non-doped Al b Ga 1-b N layer (b=0.08), N-type Al δ Ga 1-δ N layer (δ = 0.08) and the third GaN layer, the second AlGaN layer, N-type Al γ Ga 1-γ N layer, non-doped Al b Ga 1-b N layer, N-type Al δ Ga 1-δ The thickness ratio of the N layer and the third GaN layer is 1:6:1:6:1. The Al content in the second AlGaN layer decreases linearly from 0.2 to 0.08. γ Ga 1-γ The Si doping concentration in the N layer is 5.5×10 17 cm -3 , N-type Al δ Ga 1-δ The Si doping concentration in the N layer is 5.5×10 17 cm -3 .

[0217] The third multi-quantum well layer includes quantum well layers and third quantum barrier layers that are alternately stacked, and the number of cycles is 3. Each quantum well layer includes a first GaN layer, a first InGaN layer, an InGaN layer, and a third GaN layer that are sequentially stacked. x Ga 1-x N layer (x=0.15) and AlN layer, wherein the thickness of the first GaN layer is 1.2nm, the thickness of the first InGaN layer is 0.3nm, and the In composition thereof increases linearly from 0.05 to 0.15; In x Ga 1-x The thickness of the N layer is 3.2 nm, and the thickness of the AlN layer is 1.8 nm. Each third quantum barrier layer includes a third AlGaN layer, a first Si-doped GaN layer, an undoped GaN layer, a second Si-doped GaN layer, and a fourth GaN layer stacked in sequence. The thickness ratio of the third AlGaN layer, the first Si-doped GaN layer, the undoped GaN layer, the second Si-doped GaN layer, and the fourth GaN layer is 1:6:1:6:1. The Al component in the third AlGaN layer decreases linearly from 0.15 to 0.02, and the doping concentration of the first Si-doped GaN layer is 5.5×10 17 cm -3 The doping concentration of the second Si-doped GaN layer is 6.5×10 17 cm -3 .

[0218] The method for preparing the Micro-LED epitaxial wafer in this embodiment includes the following steps:

[0219] (1) Providing a substrate;

[0220] (2) growing a buffer layer on the substrate;

[0221] Specifically, an AlN layer is grown by PVD as a buffer layer.

[0222] (3) growing an intrinsic GaN layer on the buffer layer;

[0223] Specifically, the non-doped GaN layer is grown by MOCVD at a growth temperature of 1050° C. and a growth pressure of 300 torr.

[0224] (4) Growing an N-type GaN layer on the intrinsic GaN layer;

[0225] Specifically, the N-type GaN layer is grown by MOCVD at a growth temperature of 1120° C. and a growth pressure of 300 torr.

[0226] (5) growing a first multi-quantum well layer on the N-type GaN layer;

[0227] Specifically, quantum well layers and first quantum barrier layers are alternately grown on the N-type GaN layer by MOCVD until a first multi-quantum well layer is obtained, wherein the growth temperature of the quantum well layer is 780°C and the growth pressure is 200 torr; the growth temperature of the first quantum barrier layer is 940°C and the growth pressure is 200 torr.

[0228] In addition, x Ga 1-x The growth method of the N layer is as follows: first, N source (NH3), Ga source (TEGa), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 150 seconds. Then, only N source (NH3), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 15 seconds.

[0229] (6) growing a second multi-quantum well layer on the first multi-quantum well layer;

[0230] Specifically, quantum well layers and second quantum barrier layers are alternately grown on the first multi-quantum well layer by MOCVD until the second multi-quantum well layer is obtained, wherein the growth temperature of the quantum well layer is 780°C and the growth pressure is 200 torr; the growth temperature of the first quantum barrier layer is 920°C and the growth pressure is 200 torr.

[0231] In addition, x Ga 1-x The growth method of the N layer is as follows: first, N source (NH3), Ga source (TEGa), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 150 seconds. Then, only N source (NH3), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 15 seconds.

[0232] (7) growing a third multi-quantum well layer on the second multi-quantum well layer;

[0233] Specifically, quantum well layers and third quantum barrier layers are alternately grown on the second multi-quantum well layer by MOCVD until the third multi-quantum well layer is obtained, wherein the growth temperature of the quantum well layer is 780°C and the growth pressure is 200 torr; the growth temperature of the third quantum barrier layer is 900°C and the growth pressure is 200 torr.

[0234] In addition, x Ga 1-xThe growth method of the N layer is as follows: first, N source (NH3), Ga source (TEGa), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 150 seconds. Then, only N source (NH3), In source (TMIn) and carrier gas (N2) are introduced, and the growth is carried out at 780°C and 200 torr for 15 seconds.

[0235] (8) growing an electron blocking layer on the third multi-quantum well layer;

[0236] Specifically, an AlInGaN layer was grown by MOCVD as an electron blocking layer at a growth temperature of 930° C. and a growth pressure of 300 torr.

[0237] (9) Growing a P-type GaN layer on the electron blocking layer;

[0238] Specifically, the P-type GaN layer is grown by MOCVD at a growth temperature of 980° C. and a growth pressure of 400 torr.

[0239] Example 9

[0240] This embodiment provides a Micro-LED epitaxial wafer, which is different from the embodiment 8 in that:

[0241] The doping concentration of the first Si-doped GaN layer is the same as that of the second Si-doped GaN layer, both of which are 7.5×10 17 cm -3 .

[0242] The rest is the same as Example 8.

[0243] Comparative Example 1

[0244] This comparative example provides a Micro-LED epitaxial wafer, which is different from Example 1 in that:

[0245] The first multi-quantum well layer includes alternately stacked InGaN quantum well layers and GaN quantum barrier layers, wherein the In component ratio in the InGaN quantum well layer is 0.32, the thickness is 4nm, the growth temperature is 780℃, and the growth pressure is 200torr. The thickness of the GaN quantum barrier layer is 12nm, the growth resolution is 890℃, and the growth pressure is 200torr.

[0246] The rest are the same as in Example 1.

[0247] The Micro-LED epitaxial wafers obtained in Examples 1 to 9 and Comparative Example 1 were prepared into Micro-LEDs with a size of 50 μm×50 μm and a horizontal structure, and 2The brightness was tested at a current density of , and the brightness improvement rate was calculated based on the data of comparative example 1. The specific results are shown in the following table:

[0248]

[0249] It can be seen from the table that the Micro-LED epitaxial wafer in the present invention can effectively improve the luminous efficiency.

[0250] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A Micro-LED epitaxial wafer, characterized in that: It includes a substrate, an N-type GaN layer, a first multi-quantum well layer and a P-type GaN layer sequentially stacked on the substrate, wherein the first multi-quantum well layer includes a quantum well layer and a first quantum barrier layer alternately stacked; The quantum well layer includes a first GaN layer, a first InGaN layer, and an In x Ga 1-x The first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Al β Ga 1-β N layer and a second GaN layer; The In component ratio of the first InGaN layer decreases from the side close to the first GaN layer to the side close to the In x Ga 1-x The N layer side changes gradually, and the maximum value of the In component ratio in the first InGaN layer is less than or equal to the In x Ga 1-x The proportion of In component in the N layer; The Al component ratio in the first AlGaN layer decreases from the side close to the quantum well layer to the side close to the N-type Al α Ga 1-α The N-type AlGaN layer has a decreasing change, and the minimum value of the Al component ratio in the first AlGaN layer is greater than or equal to the N-type Al α Ga 1-α The proportion of Al component in the N layer.

2. The Micro-LED epitaxial wafer according to claim 1, characterized in that: In x Ga 1-x The thickness of the N layer is ≤3.5nm, and the value of x ranges from 0.1 to 0.

3.

3. The Micro-LED epitaxial wafer according to claim 1, characterized in that: α=a=β, the N-type Al α Ga 1-α The doping concentration of the N layer is related to the N-type Al β Ga 1-β The doping concentration of the N layer is the same.

4. The Micro-LED epitaxial wafer according to any one of claims 1 to 3, characterized in that: The period number of the first multi-quantum well layer is 2 to 10; The thickness of the first GaN layer is 0.5nm~5nm, the thickness of the first InGaN layer is 0.1nm~1nm, and the In component ratio is 0.01~0.3; x Ga 1-x The thickness of the N layer is 1nm~4nm; the thickness of the AlN layer is 0.5nm~5nm; The thickness of the first quantum barrier layer is 5nm~30nm; The Al component ratio in the first AlGaN layer is 0.05-0.4, and the N-type Al α Ga 1-α The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of α is 0.05~0.3; the non-doped Al a Ga 1-a The value range of a in the N layer is 0.05~0.3; β Ga 1-β The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of β is 0.05~0.

3.

5. The Micro-LED epitaxial wafer according to claim 1, wherein: It also includes a second multi-quantum well layer disposed between the first multi-quantum well layer and the P-type GaN layer, wherein the second multi-quantum well layer includes alternately stacked quantum well layers and second quantum barrier layers; The second quantum barrier layer includes a second AlGaN layer, an N-type Al γ Ga 1-γ N layer, non-doped Al b Ga 1-b N layer, N-type Al δ Ga 1-δ N layer and a third GaN layer; The Al component ratio in the second AlGaN layer decreases from the side close to the quantum well layer to the side close to the N-type Al γ Ga 1-γ The N-type AlGaN layer has a decreasing change, and the minimum value of the Al component ratio in the second AlGaN layer is greater than or equal to the N-type Al γ Ga 1-γ The proportion of Al component in the N layer; γ≠α, b≠a, δ≠β.

6. The Micro-LED epitaxial wafer according to claim 5, characterized in that: The N-type Al γ Ga 1-γ The doping concentration of the N layer is greater than that of the N-type Al α Ga 1-α The doping concentration of the N layer; δ Ga 1-δ The doping concentration of the N layer is greater than that of the N-type Al β Ga 1-β Doping concentration of the N layer.

7. The Micro-LED epitaxial wafer according to claim 5, characterized in that: The proportion of Al component in the second AlGaN layer is less than the proportion of Al component in the first AlGaN layer, γ<α, b<a, δ<β.

8. The Micro-LED epitaxial wafer according to claim 5, characterized in that: γ=b=δ, the N-type Al γ Ga 1-γ The doping concentration of the N layer is related to the N-type Al δ Ga 1-δ The doping concentration of the N layer is the same.

9. The Micro-LED epitaxial wafer according to claim 5, characterized in that: The sum of the period number of the first multi-quantum well layer and the period number of the second multi-quantum well layer is 3-15, and the ratio of the period number of the first multi-quantum well layer to the period number of the second multi-quantum well layer is 1:1-1:

2.

10. The Micro-LED epitaxial wafer according to any one of claims 5 to 9, characterized in that: The period number of the second multi-quantum well layer is 2 to 10; The thickness of the second quantum barrier layer is 5nm~30nm; The Al component ratio in the second AlGaN layer is 0.05-0.35, and the N-type Al γ Ga 1-γ The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of γ is 0.05~0.2; the non-doped Al b Ga 1-b The value range of b in the N layer is 0.05~0.2; δ Ga 1-δ The doping concentration of the N layer is 1×10 17 cm -3 ~1×10 18 cm -3 , the value range of δ is 0.05~0.

2.

11. The Micro-LED epitaxial wafer according to claim 5, characterized in that: It also includes a third multi-quantum well layer, wherein the third multi-quantum well layer is disposed between the first multi-quantum well layer and the P-type GaN layer, or the third multi-quantum well layer is disposed between the second multi-quantum well layer and the P-type GaN layer; The third multi-quantum well layer includes quantum well layers and third quantum barrier layers that are alternately stacked, and the third quantum barrier layer includes a third AlGaN layer, a first Si-doped GaN layer, an undoped GaN layer, a second Si-doped GaN layer, and a fourth GaN layer that are sequentially stacked; The proportion of Al component in the third AlGaN layer decreases from the side close to the quantum well layer to the side close to the first Si-doped GaN layer.

12. The Micro-LED epitaxial wafer according to claim 11, wherein: The doping concentration of the first Si-doped GaN layer is greater than that of the N-type Al γ Ga 1-γ The doping concentration of the N layer is greater than that of the N-type Al δ Ga 1-δ Doping concentration of the N layer.

13. The Micro-LED epitaxial wafer according to claim 11, wherein: The doping concentration of the first Si-doped GaN layer is the same as the doping concentration of the second Si-doped GaN layer.

14. The Micro-LED epitaxial wafer according to claim 11, wherein: The sum of the period number of the first multi-quantum well layer, the period number of the second multi-quantum well layer, and the period number of the third multi-quantum well layer is 3 to 15; or The sum of the period number of the first multi-quantum well layer and the period number of the third multi-quantum well layer is 3-15.

15. The Micro-LED epitaxial wafer according to claim 11, wherein: The period number of the third multi-quantum well layer is 2 to 10; The thickness of the third quantum barrier layer is 5nm~30nm; The Al component ratio in the first AlGaN layer is 0.05-0.3, and the doping concentration of the first Si-doped GaN layer is 1×10 17 cm -3 ~1×10 18 cm -3 The doping concentration of the second Si-doped GaN layer is 1×10 17 cm -3 ~1×10 18 cm -3 .

16. A method for preparing a Micro-LED epitaxial wafer, for preparing the Micro-LED epitaxial wafer according to any one of claims 1 to 15, characterized in that: include: Providing a substrate, and sequentially growing an N-type GaN layer, a first multi-quantum well layer, and a P-type GaN layer on the substrate, wherein the first multi-quantum well layer comprises quantum well layers and first quantum barrier layers that are alternately stacked; The quantum well layer includes a first GaN layer, a first InGaN layer, and an In x Ga 1-x The first quantum barrier layer includes a first AlGaN layer, an N-type Al α Ga 1-α N layer, non-doped Al a Ga 1-a N layer, N-type Al β Ga 1-β N layer and a second GaN layer; The In component ratio of the first InGaN layer decreases from the side close to the first GaN layer to the side close to the In x Ga 1-x The N layer side changes gradually, and the maximum value of the In component ratio in the first InGaN layer is less than or equal to the In x Ga 1-x The proportion of In component in the N layer; The Al component ratio in the first AlGaN layer decreases from the side close to the quantum well layer to the side close to the N-type Al α Ga 1-α The N-type AlGaN layer has a decreasing change, and the minimum value of the Al component ratio in the first AlGaN layer is greater than or equal to the N-type Al α Ga 1-α The proportion of Al component in the N layer.

17. The method for preparing a Micro-LED epitaxial wafer according to claim 16, wherein: In x Ga 1-x When the N layer grows, N source, Ga source, In source and carrier gas are first introduced, and grown at 700℃~900℃ and 50torr~300torr for 100s~200s, and then only N source, In source and carrier gas are introduced, and treated at 700℃~900℃ and 50torr~300torr for 10s~60s.

18. The method for preparing a Micro-LED epitaxial wafer according to claim 16, wherein: The growth temperature of the quantum well layer is 700° C. to 900° C., and the growth pressure is 50 torr to 300 torr; The growth temperature of the first quantum barrier layer is 800° C. to 950° C., and the growth pressure is 50 torr to 300 torr.

19. The method for preparing a Micro-LED epitaxial wafer according to claim 16, wherein: The Micro-LED epitaxial wafer further includes a second multi-quantum well layer and a third multi-quantum well layer, wherein the second multi-quantum well layer includes an alternately stacked quantum well layer and a second quantum barrier layer, and the third multi-quantum well layer includes an alternately stacked quantum well layer and a third quantum barrier layer; The growth temperature of the quantum well layer is 700° C. to 900° C., and the growth pressure is 50 torr to 300 torr; The growth temperature of the second quantum barrier layer is 800° C. to 950° C., and the growth pressure is 50 torr to 300 torr; The growth temperature of the third quantum barrier layer is 800° C. to 950° C., and the growth pressure is 50 torr to 300 torr.

20. A Micro-LED, characterized in that: Comprising the Micro-LED epitaxial wafer as described in any one of claims 1 to 15.

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