Light emitting diode epitaxial wafer and preparation method thereof

Abstract

The invention discloses a light-emitting epitaxial wafer and a preparation method thereof, and relates to the field of semiconductor photoelectric devices. The light-emitting diode epitaxial wafer sequentially comprises a substrate, a buffer layer, an N-type semiconductor layer, a multi-quantum well layer, a first electron barrier layer, a first P-type semiconductor layer, a second electron barrier layer and a second P-type semiconductor layer. The first electron blocking layer and the second electron blocking layer are both of a single-layer or multi-layer structure formed by an AlGaInN material, and the barrier height of the first electron blocking layer is larger than that of the second electron blocking layer; the first P-type semiconductor layer is of a single-layer or multi-layer structure formed by a Mg-doped AlGaInN material, the second P-type semiconductor layer is of a single-layer or multi-layer structure formed by a Mg-doped GaN material, and the doping concentration of the first P-type semiconductor layer is larger than that of the second P-type semiconductor layer. By implementing the invention, the luminous efficiency of the light-emitting diode based on the light-emitting diode epitaxial wafer can be improved.

Description

Technical Field

[0001] The invention relates to the field of semiconductor optoelectronic devices, and in particular to a light emitting diode epitaxial wafer and a preparation method thereof. Background Art

[0002] GaN-based light-emitting diodes are generally AlGaInN material systems. In this system, since electrons have higher mobility and smaller effective mass than holes, and electrons are easier to activate and have higher concentrations, the electron-hole concentration injected into the active area is extremely mismatched. The quantum wells close to the N-type semiconductor layer hardly emit light, while electrons can be easily injected into the active area or even enter the P-type semiconductor layer to cause electron leakage. Moreover, it is very difficult to obtain high-quality P-type materials with high hole concentration for light-emitting diodes, because the ionization rate of Mg in the AlGaInN material system is low, resulting in a generally low hole concentration in P-type semiconductor materials. In addition, the electron blocking layer, which is the main functional layer of the light-emitting diode, not only blocks electrons from being injected into the P-type layer to emit light, but also blocks holes from being injected into the active area, further reducing the hole concentration in the active area, resulting in a more serious problem of mismatching the electron-hole concentration in the active area. Therefore, in order to improve the luminous efficiency of GaN-based LEDs, it is very necessary to improve the hole injection efficiency of P-type materials and improve the electron-hole matching in the active area. Summary of the invention

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

[0004] In order to solve the above problems, the present invention provides a light emitting diode epitaxial wafer, which includes a substrate, a buffer layer, an N-type semiconductor layer, a multi-quantum well layer, a first electron blocking layer, a first P-type semiconductor layer, a second electron blocking layer and a second P-type semiconductor layer stacked in sequence on the substrate;

[0005] Wherein, the first electron blocking layer and the second electron blocking layer are both single-layer or multi-layer structures formed of AlGaInN material, and the barrier height of the first electron blocking layer is greater than the barrier height of the second electron blocking layer;

[0006] The first P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped AlGaInN material, the second P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped GaN material, and the doping concentration of the first P-type semiconductor layer is greater than the doping concentration of the second P-type semiconductor layer.

[0007] As an improvement of the above technical solution, the first electron blocking layer includes a first superlattice layer, a second superlattice layer and a third superlattice layer sequentially stacked on the multi-quantum well layer;

[0008] The first superlattice layer includes an AlN layer and a first GaN layer alternately stacked, and the second superlattice layer includes an Al w Ga 1-w N layer and a second GaN layer, the third superlattice layer includes an Al x Ga 1-x N layer and Mg doped with In α Ga 1-α N layers;

[0009] The first P-type semiconductor layer is Mg doped with Al a In b Ga 1-a-b N layers;

[0010] The second electron blocking layer includes a fourth superlattice layer, a fifth superlattice layer and a sixth superlattice layer sequentially stacked on the first P-type semiconductor layer;

[0011] Wherein, the fourth superlattice layer comprises Al y Ga 1-y N layer and Mg doped with In β Ga 1-β N layer; the fifth superlattice layer includes alternately stacked Al z Ga 1-z N layer and Mg doped with In γ Ga 1-γ N layer, the sixth superlattice layer includes first Mg-doped GaN layers and Mg-doped In layers alternately stacked δ Ga 1-δ N layers;

[0012] The second P-type semiconductor layer is a second Mg-doped GaN layer;

[0013] w≥x≥y≥z>a, α≤β≤γ≤δ.

[0014] As an improvement of the above technical solution, the period number of the first superlattice layer is 1 to 3, the thickness of the AlN layer is 0.36 nm to 2.9 nm, and the thickness of the first GaN layer is 0.6 nm to 5.8 nm;

[0015] The period number of the second superlattice layer is 2 to 5, and the Al w Ga 1-w The thickness of the N layer is 0.36nm to 3.6nm, and w is 0.5 to 0.8; the thickness of the second GaN layer is 0.36nm to 3.6nm;

[0016] The period number of the third superlattice layer is 2 to 6, and the Al x Ga 1-xThe thickness of the N layer is 0.36nm to 3.6nm, and x is 0.35 to 0.68; the Mg doped In α Ga 1-α The thickness of the N layer is 0.36nm~3.6nm, α is 0.02~0.08, and the doping concentration is 2.16×10 18 cm -3 ~2.53×10 19 cm -3 .

[0017] As an improvement of the above technical solution, the Mg doped Al a In b Ga 1-a-b The thickness of the N layer is 8nm~210nm, a≤0.32, b≤0.09, and the doping concentration is 1.2×10 19 cm -3 ~3.05×10 20 cm -3 ;

[0018] The thickness of the second Mg-doped GaN layer is 3.5 nm to 120 nm, and the doping concentration is 1.06×10 19 cm -3 ~8.76×10 19 cm -3 .

[0019] As an improvement of the above technical solution, the period number of the fourth superlattice layer is 2 to 5, and the Al y Ga 1-y The thickness of the N layer is 0.32nm to 3.8nm, and y is 0.3 to 0.6; the Mg doped In β Ga 1-β The thickness of the N layer is 0.32nm~3.8nm, β is 0.02~0.09, and its doping concentration is 3.51×10 18 cm -3 ~2.87×10 19 cm -3 ;

[0020] The period number of the fifth superlattice layer is 2 to 7, and the Al z Ga 1-z The thickness of the N layer is 0.32nm~3.8nm, z is 0.2~0.5; Mg is doped with In γ Ga 1-γ The thickness of the N layer is 0.32nm~3.8nm, γ is 0.03~0.12, and its doping concentration is 6.25×10 18 cm -3 ~3.67×10 19 cm -3;

[0021] The period number of the sixth superlattice layer is 3 to 10, the thickness of the first Mg-doped GaN layer is 0.32 nm to 3.8 nm, and the doping concentration is 2.35×10 18 cm -3 ~8.66×10 18 cm -3 ; The Mg doped with In δ Ga 1-δ The thickness of the N layer is 0.32nm~3.8nm, δ is 0.05~0.15, and its doping concentration is 1.16×10 19 cm -3 ~5.69×10 19 cm -3 .

[0022] As an improvement of the above technical solution, along the growth direction of the light emitting diode epitaxial wafer, the Mg doped Al a In b Ga 1-a-b The Al component and doping concentration in the N layer decrease;

[0023] Along the growth direction of the light emitting diode epitaxial wafer, the doping concentration of the second Mg-doped GaN layer decreases gradually.

[0024] As an improvement of the above technical solution, a is 0.15-0.3, and b is 0.02-0.08.

[0025] As an improvement of the above technical solution, the buffer layer is an AlN layer with a thickness of 10nm to 50nm;

[0026] The N-type semiconductor layer is an N-type GaN layer with a thickness of 1 μm to 3 μm and a Si doping concentration of 1×10 18 cm -3 ~5×10 19 cm -3 ;

[0027] The multi-quantum well layer includes alternately stacked InGaN quantum well layers and GaN quantum barrier layers, the thickness of the InGaN quantum well layer is 2nm-5nm, and the In component ratio is 0.1-0.4; the thickness of the GaN quantum barrier layer is 5nm-15nm.

[0028] Correspondingly, the present invention also 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:

[0029] Providing a substrate, and sequentially growing a buffer layer, an N-type semiconductor layer, a multi-quantum well layer, a first electron blocking layer, a first P-type semiconductor layer, a second electron blocking layer, and a second P-type semiconductor layer on the substrate;

[0030] Wherein, the first electron blocking layer and the second electron blocking layer are both single-layer or multi-layer structures formed of AlGaInN material, and the barrier height of the first electron blocking layer is greater than the barrier height of the second electron blocking layer;

[0031] The first P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped AlGaInN material, the second P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped GaN material, and the doping concentration of the first P-type semiconductor layer is greater than the doping concentration of the second P-type semiconductor layer.

[0032] As an improvement of the above technical solution, the first electron blocking layer includes a first superlattice layer, a second superlattice layer and a third superlattice layer sequentially stacked on the multi-quantum well layer;

[0033] The first superlattice layer includes an AlN layer and a first GaN layer alternately stacked, the AlN layer is grown at a temperature of 880°C to 1060°C, and a growth pressure of 30 torr to 400 torr; the first GaN layer is grown at a temperature of 880°C to 1060°C, and a growth pressure of 30 torr to 400 torr;

[0034] The second superlattice layer includes alternately stacked Al w Ga 1-w N layer and the second GaN layer, the Al w Ga 1-w The growth temperature of the N layer is 880° C. to 1060° C., and the growth pressure is 30 torr to 400 torr; the growth temperature of the second GaN layer is 880° C. to 1060° C., and the growth pressure is 30 torr to 400 torr;

[0035] The third superlattice layer includes alternately stacked Al x Ga 1-x N layer and Mg doped with In α Ga 1-α N layer; the Al x Ga 1-x The growth temperature of the N layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg doped In α Ga 1-α The growth temperature of the N layer is 830℃~980℃, and the growth pressure is 30torr~400torr;

[0036] The first P-type semiconductor layer is Mg doped with Al a In b Ga 1-a-b N layer; its growth temperature is 710℃~860℃, and its growth pressure is 30torr~650torr;

[0037] The second electron blocking layer includes a fourth superlattice layer, a fifth superlattice layer and a sixth superlattice layer sequentially stacked on the first P-type semiconductor layer;

[0038] Wherein, the fourth superlattice layer comprises Al y Ga 1-y N layer and Mg doped with In β Ga 1-β N layer; the Al y Ga 1-y The growth temperature of the N layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg doped In β Ga 1-β The growth temperature of the N layer is 830℃~1030℃, and the growth pressure is 30torr~400torr;

[0039] The fifth superlattice layer includes alternately stacked Al z Ga 1-z N layer and Mg doped with In γ Ga 1-γ N layer, the Al z Ga 1-z The growth temperature of the N layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg doped In γ Ga 1-γ The growth temperature of the N layer is 830℃~1030℃, and the growth pressure is 30torr~400torr;

[0040] The sixth superlattice layer includes first Mg-doped GaN layers and Mg-doped In layers alternately stacked δ Ga 1-δ N layer; the growth temperature of the first Mg-doped GaN layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg-doped In δ Ga 1-δ The growth temperature of the N layer is 830℃~1030℃, and the growth pressure is 30torr~400torr;

[0041] The second P-type semiconductor layer is a second Mg-doped GaN layer; its growth temperature is 880° C. to 1060° C., and its growth pressure is 300 torr to 650 torr.

[0042] The implementation of the present invention has the following beneficial effects:

[0043] In an embodiment of the present invention, a light-emitting diode epitaxial wafer is provided with a first electron blocking layer, a first P-type semiconductor layer, a second electron blocking layer and a second P-type semiconductor layer on a multi-quantum well layer in sequence; wherein, the first electron blocking layer and the second electron blocking layer are both single-layer or multi-layer structures formed of AlGaInN material, and the barrier height of the first electron blocking layer is greater than the barrier height of the second electron blocking layer; the first P-type semiconductor layer is a single-layer or multi-layer structure formed of Mg-doped AlGaInN material, the second P-type semiconductor layer is a single-layer or multi-layer structure formed of Mg-doped GaN material, and the doping concentration of the first P-type semiconductor layer is greater than the doping concentration of the second P-type semiconductor layer. Based on this structure, one can significantly weaken the blocking of the first electron blocking layer and the second electron blocking layer on hole injection into the multi-quantum well layer, thereby improving the hole injection efficiency. Both use the first P-type semiconductor layer with a higher doping concentration as the main functional layer for providing holes, which can improve the hole concentration and the efficiency of hole injection into the multi-quantum well layer, thereby improving the luminous efficiency of the light-emitting diode based on the light-emitting diode epitaxial wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic structural diagram of a light emitting diode epitaxial wafer in one embodiment of the present invention;

[0045] Figure 2 It is a flow chart of a method for preparing a light emitting diode epitaxial wafer in one embodiment of the present invention.

[0046] 100 is a substrate, 200 is a buffer layer, 300 is a non-doped semiconductor layer, 400 is an N-type semiconductor layer, 500 is a multi-quantum well layer, 600 is a first electron blocking layer, 610 is a first superlattice layer, 611 is an AlN layer, 612 is a first GaN layer, 620 is a second superlattice layer, 621 is an Al w Ga 1-w N layer, 622 is the second GaN layer, 630 is the third superlattice layer, 631 is Al x Ga 1-x N layer, 632 is Mg doped with In α Ga 1-α N layer, 700 is the first P-type semiconductor layer, 800 is the second electron blocking layer, 810 is the fourth superlattice layer, 811 is Al y Ga 1-y N layer, 812 is Mg doped with In β Ga 1-β N layer, 820 is the fifth superlattice layer, 821 is Al z Ga 1-z N layer, 822 is Mg doped with Inγ Ga 1-γ N layer, 830 is the sixth superlattice layer, 831 is the first Mg-doped GaN layer, 832 is the Mg-doped In δ Ga 1-δ The N layer 900 is a second P-type semiconductor layer. DETAILED DESCRIPTION

[0047] 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.

[0048] See also Figure 1 An embodiment of the present invention discloses a light-emitting diode epitaxial wafer, which includes a substrate 100, a buffer layer 200, an N-type semiconductor layer 400, a multi-quantum well layer 500, a first electron blocking layer 600, a first P-type semiconductor layer 700, a second electron blocking layer 800 and a second P-type semiconductor layer 900 sequentially stacked on the substrate 100.

[0049] Among them, the first electron blocking layer 600 and the second electron blocking layer 800 are both single-layer or multi-layer structures formed of AlGaInN material, and the barrier height of the first electron blocking layer 600 is greater than the barrier height of the second electron blocking layer 800; the first P-type semiconductor layer 700 is a single-layer or multi-layer structure formed of Mg-doped AlGaInN material, and the second P-type semiconductor layer 900 is a single-layer or multi-layer structure formed of Mg-doped GaN material, and the doping concentration of the first P-type semiconductor layer 700 is greater than the doping concentration of the second P-type semiconductor layer 900. Based on this structure, one can significantly weaken the blocking of the first electron blocking layer 600 and the second electron blocking layer 800 on the hole injection into the multi-quantum well layer 500, thereby improving the hole injection efficiency. Both use the first P-type semiconductor layer 700 with a higher doping concentration as the main functional layer for providing holes, which can improve the hole concentration and the efficiency of hole injection into the multi-quantum well layer 500.

[0050] Preferably, in one embodiment, the first electron blocking layer 600 includes a first superlattice layer 610 , a second superlattice layer 620 and a third superlattice layer 630 sequentially stacked on the multi-quantum well layer 500 .

[0051] The first superlattice layer 610 includes an AlN layer 611 and a first GaN layer 612 alternately stacked, and the second superlattice layer 620 includes an AlN layer 612 alternately stacked. w Ga 1-w The N layer 621 and the second GaN layer 622, the third superlattice layer 630 includes an Al x Ga 1-x N layer 631 and Mg doped with In α Ga 1-α N layer 632; the first P-type semiconductor layer 700 is Mg doped with Ala In b Ga 1-a-b N layer; the second electron blocking layer 800 includes a fourth superlattice layer 810, a fifth superlattice layer 820 and a sixth superlattice layer 830 sequentially stacked on the first P-type semiconductor layer 700; the fourth superlattice layer 810 includes an Al y Ga 1-y N layer 811 and Mg doped with In β Ga 1-β N layer 812; the fifth superlattice layer 820 includes alternately stacked Al z Ga 1-z N layer 821 and Mg doped with In γ Ga 1-γ N layer 822, the sixth superlattice layer 830 includes first Mg-doped GaN layers 831 and Mg-doped In layers 832 and 833 alternately stacked. δ Ga 1-δ N layer 832; the second P-type semiconductor layer 900 is a second Mg-doped GaN layer; and w≥x≥y≥z>a, α≤β≤γ≤δ. Among them, the wide bandgap AlN material (AlN layer 611) and AlGaN material (Al w Ga 1-w N layer 621, Al x Ga 1-x N layer 631, Al y Ga 1- y N layer 811 and Al z Ga 1-z The first electron blocking layer 600 and the second electron blocking layer 800 in the GaN material (the first GaN layer 612, the second GaN layer 622, the first Mg-doped GaN layer 831), the InGaN material (Mg-doped InGaN layer 831) and the InGaN material (Mg-doped InGaN layer 831) are mainly used to block electrons and reduce the electron mobility, thereby preventing electrons from being injected into the P-type material and causing electron leakage. α Ga 1-α N layer 632, Mg doped with In β Ga 1-β N layer 812, Mg doped with In γ Ga 1-γ N layer 822, Mg doped with In δ Ga 1-δ The N layer 832 can store some holes and reduce the blocking effect on holes, thereby improving the efficiency of hole injection into the multi-quantum well layer 500. a In b Ga 1-a-bThe N layer as the first P-type semiconductor layer 700 can improve the activation efficiency of Mg and increase the hole concentration. The second Mg-doped GaN layer as the second P-type semiconductor layer 900 can merge defects and obtain high-quality materials, thereby improving the brightness and yield of the light-emitting diode epitaxial wafer.

[0052] Specifically, in one embodiment, the period number of the first superlattice layer 610 is 1 to 3, the thickness of the AlN layer 611 is 0.36 nm to 2.9 nm, and the thickness of the first GaN layer 612 is 0.6 nm to 5.8 nm.

[0053] Specifically, in one embodiment, the period number of the second superlattice layer 620 is 2 to 5, and Al w Ga 1-w The thickness of the N layer 621 is 0.36 nm to 3.6 nm, and w is 0.5 to 0.8; the thickness of the second GaN layer 622 is 0.36 nm to 3.6 nm.

[0054] Specifically, in one embodiment, the period number of the third superlattice layer 630 is 2 to 6, and Al x Ga 1-x The thickness of the N layer 631 is 0.36 nm to 3.6 nm, and x is 0.35 to 0.68; Mg is doped with In α Ga 1-α The thickness of the N layer 632 is 0.36 nm to 3.6 nm, α is 0.02 to 0.08, and the doping concentration is 2.16×10 18 cm -3 ~2.53×10 19 cm -3 .

[0055] Specifically, in one embodiment, Mg doped with Al a In b Ga 1-a-b The thickness of the N layer is 8nm~210nm, a≤0.32, b≤0.09, and the doping concentration is 1.2×10 19 cm -3 ~3.05×10 20 cm -3 ; Preferably, a is 0.15 to 0.3, and b is 0.02 to 0.08.

[0056] Specifically, in one embodiment, the period number of the fourth superlattice layer 810 is 2 to 5, and Al y Ga 1-y The thickness of the N layer 811 is 0.32nm to 3.8nm, and y is 0.3 to 0.6; Mg is doped with In β Ga 1-βThe thickness of the N layer 812 is 0.32 nm to 3.8 nm, β is 0.02 to 0.09, and its doping concentration is 3.51×10 18 cm -3 ~2.87×10 19 cm -3 .

[0057] Specifically, in one embodiment, the period number of the fifth superlattice layer 820 is 2 to 7, and Al z Ga 1-z The thickness of the N layer 821 is 0.32nm to 3.8nm, and z is 0.2 to 0.5; Mg is doped with In γ Ga 1-γ The thickness of the N layer 822 is 0.32nm to 3.8nm, the γ is 0.03 to 0.12, and the doping concentration is 6.25×10 18 cm -3 ~3.67×10 19 cm -3 .

[0058] Specifically, in one embodiment, the period number of the sixth superlattice layer 830 is 3 to 10, the thickness of the first Mg-doped GaN layer 831 is 0.32 nm to 3.8 nm, and the doping concentration is 2.35×10 18 cm -3 ~8.66×10 18 cm -3 Mg doped with In δ Ga 1-δ The thickness of the N layer 832 is 0.32nm to 3.8nm, δ is 0.05 to 0.15, and its doping concentration is 1.16×10 19 cm -3 ~5.69×10 19 cm -3 .

[0059] Specifically, in one embodiment, the thickness of the second Mg-doped GaN layer is 3.5 nm to 120 nm, and the doping concentration is 1.06×10 19 cm -3 ~8.76×10 19 cm -3 .

[0060] Preferably, in one embodiment, along the growth direction of the light emitting diode epitaxial wafer, Mg doped with Al a In b Ga 1-a-b The Al component and doping concentration in the N layer decrease gradually. Based on this implementation, the Mg activation efficiency can be further improved and the hole concentration can be increased.

[0061] Preferably, in one embodiment, the doping concentration of the second Mg-doped GaN layer decreases along the growth direction of the light-emitting diode epitaxial wafer. Based on this implementation, defects can be better filled, crystal quality can be improved, and light-emitting efficiency can be improved.

[0062] Specifically, the substrate 100 is a sapphire substrate or a silicon substrate, but is not limited thereto.

[0063] Specifically, the buffer layer 200 is an AlN layer, a GaN layer or an AlGaN layer, but not limited thereto. The thickness of the buffer layer 200 is 10nm to 80nm, but not limited thereto. Preferably, in one embodiment, the buffer layer 200 is an AlN layer, and its thickness is 10nm to 50nm.

[0064] Specifically, the N-type semiconductor layer 400 is an N-type GaN layer or an N-type AlGaN layer, but is not limited thereto. Preferably, in one embodiment, the N-type semiconductor layer 400 is an N-type GaN layer, and its doping element is Si, but is not limited thereto. The doping concentration of Si in the N-type GaN layer is 1×10 18 cm -3 ~5×10 19 cm -3 , and its thickness is 1μm~3μm.

[0065] Specifically, the multi-quantum well layer 500 is an InGaN-GaN type multi-quantum well layer, an InGaN-AlGaN type multi-quantum well layer or an AlGaN-AlGaN type multi-quantum well layer, but is not limited thereto. Preferably, in one embodiment, the multi-quantum well layer 500 is a periodic structure, the number of periods of which is 3 to 15, and each period includes sequentially stacked InGaN quantum well layers and GaN quantum barrier layers. Among them, the In component ratio in the InGaN quantum well layer is 0.1 to 0.4, its thickness is 2nm to 5nm, and the thickness of the GaN quantum barrier layer is 5nm to 15nm.

[0066] Preferably, in one embodiment, the light emitting diode epitaxial wafer further includes a non-doped semiconductor layer 300, which is disposed between the buffer layer 200 and the N-type semiconductor layer 400, and specifically can be a non-doped GaN layer or a non-doped AlGaN layer, but is not limited thereto. Preferably, in one embodiment, the non-doped semiconductor layer 300 is a non-doped GaN layer, and its thickness is 1 μm to 5 μm.

[0067] Accordingly, see Figure 2 The present invention also provides a method for preparing a light emitting diode epitaxial wafer, which is used to prepare the above-mentioned light emitting diode epitaxial wafer, and specifically comprises the following steps:

[0068] S1: providing a substrate;

[0069] S2: sequentially growing a buffer layer, an N-type semiconductor layer, a multi-quantum well layer, a first electron blocking layer, a first P-type semiconductor layer, a second electron blocking layer and a second P-type semiconductor layer on the substrate;

[0070] Specifically, in some embodiments of the present invention, step S2 includes:

[0071] S21: growing a buffer layer on the substrate;

[0072] Specifically, in one embodiment of the present invention, an AlN layer is grown by PVD as a buffer layer.

[0073] S22: growing a non-doped semiconductor layer on the buffer layer;

[0074] Specifically, in one embodiment of the present invention, a non-doped GaN layer is grown by MOCVD as a non-doped semiconductor layer, and its growth temperature is 1000° C. to 1200° C. and its growth pressure is 100 torr to 500 torr.

[0075] S23: growing an N-type semiconductor layer on the non-doped semiconductor layer;

[0076] Specifically, in one embodiment of the present invention, an N-type GaN layer is grown by MOCVD as the N-type semiconductor layer, and its growth temperature is 1100° C. to 1200° C. and its growth pressure is 100 torr to 500 torr.

[0077] S24: growing a multi-quantum well layer on the N-type semiconductor layer;

[0078] Specifically, in one embodiment, an InGaN quantum well layer and a GaN quantum barrier layer are periodically grown on an N-type semiconductor layer by MOCVD until a multi-quantum well layer is obtained.

[0079] The growth temperature of the InGaN quantum well layer is 760°C to 850°C, and the growth pressure is 50 torr to 300 torr. The growth temperature of the GaN quantum barrier layer is 850°C to 950°C, and the growth pressure is 50 torr to 300 torr.

[0080] S25: growing a first electron blocking layer on the multi-quantum well layer;

[0081] Specifically, in one embodiment, step S25 includes:

[0082] S251: growing a first superlattice layer on the multi-quantum well layer;

[0083] Specifically, in one implementation, an AlN layer and a first GaN layer are periodically grown by MOCVD until a first superlattice layer is obtained, wherein the AlN layer is grown at a temperature of 880°C to 1060°C and a growth pressure of 30 torr to 400 torr; the first GaN layer is grown at a temperature of 880°C to 1060°C and a growth pressure of 30 torr to 400 torr.

[0084] S252: growing a second superlattice layer on the first superlattice layer;

[0085] Specifically, in one embodiment, Al is periodically grown by MOCVD. w Ga 1-w N layer and the second GaN layer until the second superlattice layer is obtained. w Ga 1-w The growth temperature of the N layer is 880° C. to 1060° C., and the growth pressure is 30 torr to 400 torr; the growth temperature of the second GaN layer is 880° C. to 1060° C., and the growth pressure is 30 torr to 400 torr.

[0086] S253: growing a third superlattice layer on the second superlattice layer to obtain a first electron blocking layer;

[0087] Specifically, in one embodiment, Al is periodically grown by MOCVD. x Ga 1-x N layer and Mg doped with In α Ga 1-α N layers until the third superlattice layer is obtained. x Ga 1-x The growth temperature of the N layer is 880℃~1060℃, and the growth pressure is 30torr~400torr; Mg doped with In α Ga 1-α The growth temperature of the N layer is 830° C. to 980° C., and the growth pressure is 30 torr to 400 torr.

[0088] S26: growing a first P-type semiconductor layer on the first electron blocking layer;

[0089] Specifically, in one embodiment, Mg-doped Al is grown by MOCVD. a In b Ga 1-a-b The N layer, as the first P-type semiconductor layer, has a growth temperature of 710° C. to 860° C. and a growth pressure of 30 torr to 650 torr.

[0090] S27: growing a second electron blocking layer on the first P-type semiconductor layer;

[0091] Specifically, in one embodiment, S27 includes the following steps:

[0092] S271: growing a fourth superlattice layer on the first P-type semiconductor layer;

[0093] Specifically, in one embodiment, Al is periodically grown by MOCVD. y Ga 1-y N layer and Mg doped with In β Ga 1-β N layers until the fourth superlattice layer is obtained. y Ga 1-y The growth temperature of the N layer is 880℃~1060℃, and the growth pressure is 30torr~400torr; Mg doped with In β Ga 1-β The growth temperature of the N layer is 830° C. to 1030° C., and the growth pressure is 30 torr to 400 torr.

[0094] S272: growing a fifth superlattice layer on the fourth superlattice layer;

[0095] Specifically, in one embodiment, Al is periodically grown by MOCVD. z Ga 1-z N layer and Mg doped with In γ Ga 1-γ N layers are formed until the fifth superlattice layer is obtained. z Ga 1-z The growth temperature of the N layer is 880℃~1060℃, and the growth pressure is 30torr~400torr; Mg doped with In γ Ga 1-γ The growth temperature of the N layer is 830° C. to 1030° C., and the growth pressure is 30 torr to 400 torr.

[0096] S273: growing a sixth superlattice layer on the fifth superlattice layer to obtain a second electron blocking layer;

[0097] Specifically, in one embodiment, a first Mg-doped GaN layer and a Mg-doped In layer are periodically grown by MOCVD. δ Ga 1-δ N layer, until the sixth superlattice layer is obtained, wherein the growth temperature of the first Mg-doped GaN layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg-doped In δ Ga 1-δ The growth temperature of the N layer is 830° C. to 1030° C., and the growth pressure is 30 torr to 400 torr.

[0098] S28: growing a second P-type semiconductor layer on the second electron blocking layer;

[0099] Specifically, in one embodiment, a second Mg-doped GaN layer is grown by MOCVD as the second P-type semiconductor layer, and the growth temperature is 880° C. to 1060° C. and the growth pressure is 300 torr to 650 torr.

[0100] The present invention will be further described below with specific embodiments:

[0101] Example 1

[0102] The present embodiment provides a light-emitting diode epitaxial wafer, which includes a substrate, a buffer layer, an undoped semiconductor layer, an N-type semiconductor layer, a multi-quantum well layer, a first electron blocking layer, a first P-type semiconductor layer, a second electron blocking layer and a second P-type semiconductor layer stacked in sequence on the substrate.

[0103] The substrate is a sapphire substrate. The buffer layer is an AlN layer with a thickness of 30 nm. The non-doped semiconductor layer is a non-doped GaN layer with a thickness of 2.5 μm. The N-type semiconductor layer is an N-type GaN layer with a thickness of 2 μm and a Si doping concentration of 1×10 19 cm -3 The multi-quantum well layer includes alternately stacked InGaN quantum well layers and GaN quantum barrier layers, and the number of cycles is 10. The In component ratio in the InGaN quantum well layer is 0.2, and its thickness is 3nm, and the thickness of the GaN quantum barrier layer is 10nm.

[0104] The first electron blocking layer includes a first superlattice layer, a second superlattice layer and a third superlattice layer stacked on the multi-quantum well layer in sequence; the first superlattice layer includes an AlN layer and a first GaN layer stacked alternately, and the number of cycles is 2. The thickness of the AlN layer is 2nm, and the thickness of the first GaN layer is 5nm. The second superlattice layer includes an AlN layer stacked alternately. w Ga 1-w N layer (w = 0.75) and the second GaN layer, the period number is 4, Al w Ga 1-w The thickness of the N layer is 2nm, and the thickness of the second GaN layer is 3nm. The third superlattice layer includes alternately stacked Al x Ga 1-x N layer (x = 0.65) and Mg doped In α Ga 1-α N layer (α = 0.03), the number of periods is 5, Al x Ga 1-x The thickness of the N layer is 2nm, and the Mg is doped with In α Ga 1-α The thickness of the N layer is 3 nm and the doping concentration is 3.5×1018 cm -3 .

[0105] Among them, the first P-type semiconductor layer is Mg doped with Al a In b Ga 1-a-b The N layer (a = 0.2, b = 0.05) has a thickness of 150 nm and a doping concentration of 1.5 × 10 20 cm -3 .

[0106] The second electron blocking layer includes a fourth superlattice layer, a fifth superlattice layer and a sixth superlattice layer sequentially stacked on the first P-type semiconductor layer; the fourth superlattice layer includes an Al y Ga 1-y N layer (y = 0.55) and Mg doped In β Ga 1-β N layer (β = 0.05), the number of periods is 4, Al y Ga 1-y The thickness of the N layer is 2.5 nm, and the Mg is doped with In β Ga 1-β The thickness of the N layer is 3 nm and its doping concentration is 5.5×10 18 cm -3 The fifth superlattice layer includes alternately stacked Al z Ga 1-z N layer (z = 0.4) and Mg doped In γ Ga 1-γ N layers (γ=0.1), period number is 5, Al z Ga 1-z The thickness of the N layer is 2nm, and the Mg is doped with In γ Ga 1-γ The thickness of the N layer is 3 nm and its doping concentration is 8.5×10 18 cm -3 The sixth superlattice layer includes a first Mg-doped GaN layer and a Mg-doped In layer alternately stacked δ Ga 1-δ N layer (δ=0.12), the period number is 8, the thickness of the first Mg-doped GaN layer is 3nm, and its doping concentration is 6.5×10 18 cm -3 Mg doped with In δ Ga 1-δ The thickness of the N layer is 2.2 nm, and its doping concentration is 2.2×10 19 cm -3 .

[0107] The second P-type semiconductor layer is a second Mg-doped GaN layer with a thickness of 50 nm and a doping concentration of 5.6×1019 cm -3 .

[0108] The method for preparing the light emitting diode epitaxial wafer in this embodiment comprises the following steps:

[0109] (1) providing a substrate;

[0110] (2) growing a buffer layer on the substrate;

[0111] Specifically, an AlN layer is grown by PVD to serve as a buffer layer.

[0112] (3) growing a non-doped semiconductor layer on the buffer layer;

[0113] Specifically, the non-doped GaN layer is grown by MOCVD, and the growth temperature of the non-doped GaN layer is 1080° C. and the growth pressure is 300 torr.

[0114] (4) growing an N-type semiconductor layer on the non-doped semiconductor layer;

[0115] Specifically, an N-type GaN layer is grown by MOCVD as the N-type semiconductor layer, and the growth temperature is 1180° C. and the growth pressure is 400 torr.

[0116] (5) growing a multi-quantum well layer on the N-type semiconductor layer;

[0117] Specifically, an InGaN quantum well layer and a GaN quantum barrier layer are periodically grown on an N-type semiconductor layer by MOCVD until a multi-quantum well layer is obtained. The growth temperature of the InGaN quantum well layer is 780°C and the growth pressure is 200 torr. The growth temperature of the GaN quantum barrier layer is 920°C and the growth pressure is 200 torr.

[0118] (6) growing a first superlattice layer on the multi-quantum well layer;

[0119] Specifically, an AlN layer and a first GaN layer are periodically grown by MOCVD until a first superlattice layer is obtained, wherein the AlN layer is grown at a temperature of 960° C. and a growth pressure of 200 torr; and the first GaN layer is grown at a temperature of 1020° C. and a growth pressure of 200 torr.

[0120] (7) growing a second superlattice layer on the first superlattice layer;

[0121] Specifically, Al is grown periodically by MOCVD. w Ga 1-w N layer and the second GaN layer until the second superlattice layer is obtained. w Ga 1-wThe growth temperature of the N layer is 1040° C. and the growth pressure is 200 torr; the growth temperature of the second GaN layer is 920° C. and the growth pressure is 200 torr.

[0122] (8) growing a third superlattice layer on the second superlattice layer to obtain a first electron blocking layer;

[0123] Specifically, Al is grown periodically by MOCVD. x Ga 1-x N layer and Mg doped with In α Ga 1-α N layers until the third superlattice layer is obtained. x Ga 1-x The growth temperature of the N layer is 1030℃ and the growth pressure is 200torr; Mg doped with In α Ga 1-α The growth temperature of the N layer is 880°C and the growth pressure is 200 torr.

[0124] (9) growing a first P-type semiconductor layer on the first electron blocking layer;

[0125] Specifically, Mg-doped Al is grown by MOCVD a In b Ga 1-a-b The N layer, as the first P-type semiconductor layer, has a growth temperature of 830° C. and a growth pressure of 600 torr.

[0126] (10) growing a fourth superlattice layer on the first P-type semiconductor layer;

[0127] Specifically, Al is grown periodically by MOCVD. y Ga 1-y N layer and Mg doped with In β Ga 1-β N layers until the fourth superlattice layer is obtained. y Ga 1-y The growth temperature of the N layer is 960℃ and the growth pressure is 200torr; Mg doped with In β Ga 1-β The growth temperature of the N layer is 880°C and the growth pressure is 200 torr.

[0128] (11) growing a fifth superlattice layer on the fourth superlattice layer;

[0129] Specifically, Al is grown periodically by MOCVD. z Ga 1-z N layer and Mg doped with In γ Ga 1-γ N layers are formed until the fifth superlattice layer is obtained.z Ga 1-z The growth temperature of the N layer is 1030℃ and the growth pressure is 300torr; Mg doped with In γ Ga 1-γ The growth temperature of the N layer is 850°C and the growth pressure is 300 torr.

[0130] (12) growing a sixth superlattice layer on the fifth superlattice layer to obtain a second electron blocking layer;

[0131] Specifically, the first Mg-doped GaN layer and the Mg-doped In layer are periodically grown by MOCVD. δ Ga 1-δ N layer until the sixth superlattice layer is obtained, wherein the growth temperature of the first Mg-doped GaN layer is 1040°C and the growth pressure is 200 torr; the Mg-doped In δ Ga 1-δ The growth temperature of the N layer is 840°C and the growth pressure is 200 torr;

[0132] (13) growing a second P-type semiconductor layer on the second electron blocking layer;

[0133] Specifically, a second Mg-doped GaN layer is grown by MOCVD as the second P-type semiconductor layer, and the growth temperature is 1040° C. and the growth pressure is 500 torr.

[0134] Example 2

[0135] This embodiment provides a light emitting diode epitaxial wafer, which is different from the embodiment 1 in that:

[0136] Along the growth direction of the LED epitaxial wafer, Mg doped with Al a In b Ga 1-a-b The Al component and doping concentration in the N layer decrease linearly.

[0137] The rest are the same as in Example 1.

[0138] Example 3

[0139] This embodiment provides a light emitting diode epitaxial wafer, which is different from the embodiment 2 in that:

[0140] Along the growth direction of the light emitting diode epitaxial wafer, the doping concentration of the second Mg-doped GaN layer changes linearly and gradually.

[0141] The rest is the same as Example 2.

[0142] Comparative Example 1

[0143] This comparative example provides a light emitting diode epitaxial wafer, which differs from Example 1 in that:

[0144] An electron blocking layer and a P-type GaN layer are provided on the multi-quantum well layer. The electron blocking layer is an AlGaN layer with a thickness of 50nm and an Al component ratio of 0.55. The thickness of the P-type GaN layer is 200nm and the Mg doping concentration is 3.5×10 20 cm -3 .

[0145] The electron blocking layer is grown by MOCVD at a growth temperature of 1020°C and a growth pressure of 300 torr; the P-type GaN layer is grown at a temperature of 980°C and a growth pressure of 400 torr.

[0146] The rest are the same as in Example 1.

[0147] The light-emitting diode epitaxial wafers obtained in Examples 1 to 3 and Comparative Example 1 were prepared into chips with a size of 10 mil×24 mil in a front-mounted structure, and the luminous brightness was measured at 120 mA, and the brightness improvement rate was calculated based on the data of Comparative Example 1. The specific results are shown in the following table:

[0148] Brightness increase rate / % Example 1 0.78 Example 2 1.12 Example 3 1.33 Comparative Example 1 -

[0149] 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 light emitting diode epitaxial wafer, characterized in that: It includes a substrate, a buffer layer, an N-type semiconductor layer, a multi-quantum well layer, a first electron blocking layer, a first P-type semiconductor layer, a second electron blocking layer and a second P-type semiconductor layer stacked in sequence on the substrate; Wherein, the first electron blocking layer and the second electron blocking layer are both single-layer or multi-layer structures formed of AlGaInN material, and the barrier height of the first electron blocking layer is greater than the barrier height of the second electron blocking layer; The first P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped AlGaInN material, the second P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped GaN material, and the doping concentration of the first P-type semiconductor layer is greater than the doping concentration of the second P-type semiconductor layer.

2. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The first electron blocking layer includes a first superlattice layer, a second superlattice layer and a third superlattice layer sequentially stacked on the multi-quantum well layer; The first superlattice layer includes an AlN layer and a first GaN layer alternately stacked, and the second superlattice layer includes an Al w Ga 1-w N layer and a second GaN layer, the third superlattice layer includes an Al x Ga 1-x N layer and Mg doped with In α Ga 1-α N layers; The first P-type semiconductor layer is Mg doped with Al a In b Ga 1-a-b N layers; The second electron blocking layer includes a fourth superlattice layer, a fifth superlattice layer and a sixth superlattice layer sequentially stacked on the first P-type semiconductor layer; The fourth superlattice layer includes alternately stacked Al y Ga 1-y N layer and Mg doped with In β Ga 1-β N layer; the fifth superlattice layer includes alternately stacked Al z Ga 1-z N layer and Mg doped with In γ Ga 1-γ N layer, the sixth superlattice layer includes first Mg-doped GaN layers and Mg-doped In layers alternately stacked δ Ga 1-δ N layers; The second P-type semiconductor layer is a second Mg-doped GaN layer; w≥x≥y≥z>a, α≤β≤γ≤δ.

3. The light emitting diode epitaxial wafer according to claim 2, characterized in that: The period number of the first superlattice layer is 1 to 3, the thickness of the AlN layer is 0.36 nm to 2.9 nm, and the thickness of the first GaN layer is 0.6 nm to 5.8 nm; The period number of the second superlattice layer is 2 to 5, and the Al w Ga 1-w The thickness of the N layer is 0.36nm to 3.6nm, and w is 0.5 to 0.8; the thickness of the second GaN layer is 0.36nm to 3.6nm; The period number of the third superlattice layer is 2 to 6, and the Al x Ga 1-x The thickness of the N layer is 0.36nm to 3.6nm, and x is 0.35 to 0.68; the Mg doped In α Ga 1-α The thickness of the N layer is 0.36nm~3.6nm, α is 0.02~0.08, and the doping concentration is 2.16×10 18 cm -3 ~2.53×10 19 cm -3 .

4. The light emitting diode epitaxial wafer according to claim 2, characterized in that: The Mg doped Al a In b Ga 1-a-b The thickness of the N layer is 8nm~210nm, a≤0.32, b≤0.09, and the doping concentration is 1.2×10 19 cm -3 ~3.05×10 20 cm -3 ; The thickness of the second Mg-doped GaN layer is 3.5 nm to 120 nm, and the doping concentration is 1.06×10 19 cm -3 ~8.76×10 19 cm -3 .

5. The light emitting diode epitaxial wafer according to claim 2, characterized in that: The period number of the fourth superlattice layer is 2 to 5, and the Al y Ga 1-y The thickness of the N layer is 0.32nm to 3.8nm, and y is 0.3 to 0.6; the Mg doped In β Ga 1-β The thickness of the N layer is 0.32nm~3.8nm, β is 0.02~0.09, and its doping concentration is 3.51×10 18 cm -3 ~2.87×10 19 cm -3 ; The period number of the fifth superlattice layer is 2 to 7, and the Al z Ga 1-z The thickness of the N layer is 0.32nm~3.8nm, z is 0.2~0.5; Mg is doped with In γ Ga 1-γ The thickness of the N layer is 0.32nm~3.8nm, γ is 0.03~0.12, and its doping concentration is 6.25×10 18 cm -3 ~3.67×10 19 cm -3 ; The period number of the sixth superlattice layer is 3 to 10, the thickness of the first Mg-doped GaN layer is 0.32 nm to 3.8 nm, and the doping concentration is 2.35×10 18 cm -3 ~8.66×10 18 cm -3 ; The Mg doped with In δ Ga 1-δ The thickness of the N layer is 0.32nm~3.8nm, δ is 0.05~0.15, and its doping concentration is 1.16×10 19 cm -3 ~5.69×10 19 cm -3 .

6. The light emitting diode epitaxial wafer according to claim 2, characterized in that: Along the growth direction of the LED epitaxial wafer, the Mg doped Al a In b Ga 1-a-b The Al component and doping concentration in the N layer decrease; Along the growth direction of the light emitting diode epitaxial wafer, the doping concentration of the second Mg-doped GaN layer decreases gradually.

7. The light emitting diode epitaxial wafer according to claim 4, characterized in that: a is 0.15~0.3, b is 0.02~0.

08.

8. The light emitting diode epitaxial wafer according to any one of claims 1 to 7, characterized in that: The buffer layer is an AlN layer, and its thickness is 10nm to 50nm; The N-type semiconductor layer is an N-type GaN layer with a thickness of 1 μm to 3 μm and a Si doping concentration of 1×10 18 cm -3 ~5×10 19 cm -3 ; The multi-quantum well layer includes alternately stacked InGaN quantum well layers and GaN quantum barrier layers, the thickness of the InGaN quantum well layer is 2nm-5nm, and the In component ratio is 0.1-0.4; the thickness of the GaN quantum barrier layer is 5nm-15nm.

9. A method for preparing a light emitting diode epitaxial wafer, used for preparing the light emitting diode epitaxial wafer according to any one of claims 1 to 8, characterized in that: include: Providing a substrate, and sequentially growing a buffer layer, an N-type semiconductor layer, a multi-quantum well layer, a first electron blocking layer, a first P-type semiconductor layer, a second electron blocking layer, and a second P-type semiconductor layer on the substrate; Wherein, the first electron blocking layer and the second electron blocking layer are both single-layer or multi-layer structures formed of AlGaInN material, and the barrier height of the first electron blocking layer is greater than the barrier height of the second electron blocking layer; The first P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped AlGaInN material, the second P-type semiconductor layer is a single-layer or multi-layer structure formed by Mg-doped GaN material, and the doping concentration of the first P-type semiconductor layer is greater than the doping concentration of the second P-type semiconductor layer.

10. The method for preparing a light emitting diode epitaxial wafer according to claim 1, characterized in that: The first electron blocking layer includes a first superlattice layer, a second superlattice layer and a third superlattice layer sequentially stacked on the multi-quantum well layer; The first superlattice layer includes an AlN layer and a first GaN layer alternately stacked, the AlN layer is grown at a temperature of 880°C to 1060°C, and a growth pressure of 30 torr to 400 torr; the first GaN layer is grown at a temperature of 880°C to 1060°C, and a growth pressure of 30 torr to 400 torr; The second superlattice layer includes Al w Ga 1-w N layer and the second GaN layer, the Al w Ga 1-w The growth temperature of the N layer is 880° C. to 1060° C., and the growth pressure is 30 torr to 400 torr; the growth temperature of the second GaN layer is 880° C. to 1060° C., and the growth pressure is 30 torr to 400 torr; The third superlattice layer includes alternately stacked Al x Ga 1-x N layer and Mg doped with In α Ga 1-α N layer; the Al x Ga 1-x The growth temperature of the N layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg doped In α Ga 1-α The growth temperature of the N layer is 830℃~980℃, and the growth pressure is 30torr~400torr; The first P-type semiconductor layer is Mg doped with Al a In b Ga 1-a-b N layer; its growth temperature is 710℃~860℃, and its growth pressure is 30torr~650torr; The second electron blocking layer includes a fourth superlattice layer, a fifth superlattice layer and a sixth superlattice layer sequentially stacked on the first P-type semiconductor layer; The fourth superlattice layer includes alternately stacked Al y Ga 1-y N layer and Mg doped with In β Ga 1-β N layer; the Al y Ga 1-y The growth temperature of the N layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg doped In β Ga 1-β The growth temperature of the N layer is 830℃~1030℃, and the growth pressure is 30torr~400torr; The fifth superlattice layer includes alternately stacked Al z Ga 1-z N layer and Mg doped with In γ Ga 1-γ N layer, the Al z Ga 1-z The growth temperature of the N layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg doped In γ Ga 1-γ The growth temperature of the N layer is 830℃~1030℃, and the growth pressure is 30torr~400torr; The sixth superlattice layer includes first Mg-doped GaN layers and Mg-doped In layers alternately stacked δ Ga 1-δ N layer; the growth temperature of the first Mg-doped GaN layer is 880°C to 1060°C, and the growth pressure is 30torr to 400torr; the Mg-doped In δ Ga 1-δ The growth temperature of the N layer is 830℃~1030℃, and the growth pressure is 30torr~400torr; The second P-type semiconductor layer is a second Mg-doped GaN layer; its growth temperature is 880° C. to 1060° C., and its growth pressure is 300 torr to 650 torr.

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