Anti-hydrolysis blue-green light led epitaxial structure and preparation method thereof, and anti-hydrolysis blue-green light led

Abstract

The application discloses an anti-hydrolysis blue-green light LED epitaxial structure and a preparation method and anti-hydrolysis blue-green light LED thereof, and relates to the field of semiconductor photoelectric devices. The epitaxial structure comprises a substrate and a buffer layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer and a P-GaN layer arranged on the substrate in sequence, the buffer layer comprises BN layers, B x Ga 1‑x N layers and Al y Ga 1‑y N layers which are stacked in sequence, wherein x is 0.1-0.2 and y is 0.1-0.2. The anti-hydrolysis performance of the blue-green light LED can be improved by implementing the application.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor optoelectronic devices, in particular to an anti-hydrolysis blue-green LED epitaxial structure and a preparation method thereof, and an anti-hydrolysis blue-green LED. BACKGROUND

[0002] During use, the LED reacts with water / water vapor remaining in the external environment or the packaging glue, causing chip hydrolysis. This results in problems such as electrode peeling, LED light-emitting chip dimming, and dead light. Further, the hydrolysis product produced by hydrolysis also climbs to the light-emitting structure (epitaxy) part of the LED chip, causing PN junction conduction and further causing side leakage problems. Both of these significantly reduce the reliability of the LED.

[0003] The existing way to improve the anti-hydrolysis performance is to perform ISO deep etching on the epitaxial structure and add a thick passivation film forming process in the subsequent chip process, thereby preventing side leakage. However, such a passivation film will absorb light, reducing the light efficiency. At the same time, the deposition process often cannot guarantee that a passivation film with uniform thickness is formed on the side wall and the plane. Therefore, in order to deposit a thicker passivation film on the side wall, it often means that a passivation film with an even greater thickness is deposited on other planes, which increases the cost and further reduces the light efficiency. SUMMARY

[0004] The technical problem to be solved by the present application is to provide an anti-hydrolysis blue-green LED epitaxial structure and a preparation method thereof, which can improve the anti-hydrolysis performance of the blue-green LED.

[0005] The technical problem to be solved by the present application is to provide an anti-hydrolysis blue-green LED epitaxial structure and a preparation method thereof, which can improve the anti-hydrolysis performance of the blue-green LED.

[0006] To solve the above problems, the present application discloses an anti-hydrolysis blue-green LED epitaxial structure, which comprises a substrate and a buffer layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer and a P-GaN layer arranged in sequence on the substrate. x Ga 1-x N layer and an Al y Ga 1-y N layer, wherein x is 0.1-0.2 and y is 0.1-0.2.

[0007] As an improvement of the above technical solution, the thickness of the BN layer is 5-10 nm, the thickness of the B x Ga 1-x N layer is 10-20 nm, and the thickness of the Al y Ga 1-y N layer is 10-20 nm.

[0008] As the improvement of the above technical solution, the N-GaN layer comprises a first N-GaN layer, a composite insertion layer and a second N-GaN layer which are stacked in sequence.

[0009] The composite insertion layer is N-B z Ga 1-z N layer and N-Al w Ga 1-w N layer, and the period number of the periodic superlattice structure is greater than or equal to 2, wherein z is 0.1-0.2, and w is 0.1-0.2.

[0010] As the improvement of the above technical solution, the thickness of the first N-GaN layer is 200-500nm, and the thickness of the second N-GaN layer is 800-1500nm.

[0011] The doping element of the first N-GaN layer is Si, and the doping concentration is 3×10 18 -9×10 18 cm -3 ; the doping element of the second N-GaN layer is Si, and the doping concentration is 1×10 19 -5×10 19 cm -3 .

[0012] As the improvement of the above technical solution, the period number of the composite insertion layer is 10-20.

[0013] In each period, the thickness of the N-B z Ga 1-z N layer is 5-10nm, and the thickness of the N-Al w Ga 1-w N layer is 20-40nm.

[0014] As the improvement of the above technical solution, the doping element of the N-B z Ga 1-z N layer is Si, and the doping concentration is 8×10 17 -2×10 18 cm -3 ; and the doping element of the N-Al w Ga 1-w N layer is Si, and the doping concentration is 8×10 17 -3×10 18 cm -3 .

[0015] Correspondingly, the application also discloses an anti-hydrolysis blue-green LED epitaxial structure.

[0016] A substrate is provided, and a buffer layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer and a P-GaN layer are sequentially grown on the substrate;

[0017] The buffer layer comprises a BN layer, a B x Ga 1-x N layer and an Al y Ga 1-y N layer which are sequentially stacked, wherein x is 0.1-0.2 and y is 0.1-0.2.

[0018] As an improvement of the above technical solution, the growth temperature of the BN layer is 780-880℃, and the growth pressure is 20-200torr.

[0019] The growth temperature of the B x Ga 1-x N layer is 1000-1100℃, and the growth pressure is 100-300torr.

[0020] The growth temperature of the Al y Ga 1-y N layer is 700-900℃, and the growth pressure is 50-200torr.

[0021] As an improvement of the above technical solution, the N-GaN layer comprises a first N-GaN layer, a composite insertion layer and a second N-GaN layer which are sequentially stacked; wherein the composite insertion layer is a periodic superlattice structure composed of a N-B z Ga 1-z N layer and a N-Al w Ga 1-w N layer, and the number of periods is greater than or equal to 2, wherein z is 0.1-0.2 and w is 0.1-0.2.

[0022] The growth temperature of the first N-GaN layer and the second N-GaN layer is 1050-1150℃, and the growth pressure is 100-300torr.

[0023] The growth temperature of the composite insertion layer is 900-1000℃, and the growth pressure is 100-300torr.

[0024] Correspondingly, the application also discloses a hydrolysis-resistant blue-green LED, which comprises the above-mentioned epitaxial structure for a hydrolysis-resistant blue-green LED.

[0025] The application has the following beneficial effects:

[0026] 1. The epitaxial structure for a hydrolysis-resistant blue-green LED of the application adopts a BN layer, a B x Ga 1-x N layer and an Al y Ga1-y The N layer and the GaN layer together serve as a buffer layer. The lattice constant (a=0.253) of BN is smaller than the lattice constant (a=0.3189 nm) of GaN, which can significantly reduce the lattice mismatch between the substrate and the GaN-based epitaxial layer, reduce the dislocation density, and improve the crystal quality of the epitaxial layer. x Ga 1-x The N layer can significantly reduce the background carrier concentration, improve the resistivity of the U-GaN layer, and reduce the defect density. Such a structure design can improve the crystal quality and improve the hydrolysis resistance.

[0027] 2. The anti-hydrolysis blue-green LED epitaxial structure of the application inserts a composite insertion layer in the N-GaN layer, which is a periodic superlattice structure composed of a B z Ga 1-z N layer and an Al w Ga 1-w N layer. Firstly, the atomic radius of B atoms and Al atoms is relatively small, which can fill the vacancies caused by dislocations and further reduce the extension of lattice mismatch. Secondly, the tensile stress introduced by the two layers can offset the partial compressive stress accumulated during high-temperature GaN growth. Thirdly, the band gap of BN is between that of AlN and GaN, Eg(BN)=5.8eV, Eg(AlN)=6.15eV, and Eg(GaN)=3.4eV, thereby improving the electron blocking rate and improving the hydrolysis resistance. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structure diagram of the anti-hydrolysis blue-green LED epitaxial structure in an embodiment of the application;

[0029] Figure 2 is a structure diagram of the buffer layer in an embodiment of the application;

[0030] Figure 3 is a structure diagram of the N-GaN layer in an embodiment of the application;

[0031] Figure 4 is a flow chart of the preparation method of the anti-hydrolysis blue-green LED epitaxial structure in an embodiment of the application. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions and advantages of the application clearer, the application is further described in detail below.

[0033] Reference Figure 1 and Figure 2The application discloses an anti-hydrolysis epitaxial structure for blue-green LED, which comprises a substrate 1 and a buffer layer 2, a U-GaN layer 3, an N-GaN layer 4, a multi-quantum well layer 5, an electron blocking layer 6 and a P-GaN layer 7 arranged on the substrate 1 in sequence. The buffer layer 2 comprises BN layers 21, B x Ga 1-x N layers 22 (x is 0.1-0.2) and Al y Ga 1-y N layers 23 (0.1-0.2) arranged in sequence. Based on the structure, the crystal quality of the GaN-based epitaxial layer can be effectively improved, and the anti-hydrolysis performance is improved.

[0034] The lattice constant of the BN layer 21 is small, so that the lattice mismatch degree between the substrate and the GaN-based epitaxial layer can be obviously reduced, the dislocation density is reduced, and the crystal quality of the epitaxial layer is improved. Specifically, the thickness of the BN layer 21 is 5-10 nm, and is exemplarily 5.5 nm, 6 nm, 6.5 nm, 7 nm, 7.5 nm, 8 nm or 8.5 nm.

[0035] The B x Ga 1-x N layer 22 can significantly reduce the background carrier concentration, improve the resistivity of the U-GaN layer 3 and reduce the defect density. Specifically, the thickness of the B x Ga 1-x N layer 22 is 10-20 nm, and is exemplarily 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm or 18 nm, but is not limited thereto.

[0036] The Al y Ga 1-y N layer 23 is 10-20 nm, and is exemplarily 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm or 18 nm, but is not limited thereto.

[0037] Specifically, in an embodiment of the application, the N-GaN layer 4 is a Si-doped GaN layer, the doping concentration of which is 5*10 18 -5*10 19 cm -3 -3, and the thickness is 1-4 microns, and is exemplarily 1.3 microns, 1.6 microns, 2.2 microns, 2.5 microns, 3.1 microns, 3.4 microns or 3.7 microns, but is not limited thereto.

[0038] Preferably, the N-GaN layer 4 is a Si-doped GaN layer, the doping concentration of which is 5*10 Figure 3In another embodiment of the present application, a composite doping layer 43 is inserted in the N-GaN layer 4, i.e. comprising a first N-GaN layer 41, a composite insertion layer 42 and a second N-GaN layer 43 stacked in sequence; wherein the composite insertion layer 42 is an N-B z Ga 1-z N layer 421 and an N-Al w Ga 1-w N layer 422, the period number of which is ≥2, wherein z is 0.1-0.2 and w is 0.1-0.2. Firstly, since the atomic radii of B atom and Al atom are relatively small, the composite insertion layer 42 can fill the vacancies caused by dislocations, further reducing the extension of lattice mismatch. Secondly, the tensile stress introduced by the composite insertion layer 42 can offset part of the compressive stress accumulated during high-temperature GaN growth. Thirdly, the band gap of BN is between that of AlN and GaN, Eg(BN) = 5.8eV, Eg(AlN) = 6.15eV, and Eg(GaN) = 3.4eV, thereby improving the electron blocking rate. In combination of the above three, the water hydrolysis resistance can be effectively improved.

[0039] Specifically, the period number of the composite insertion layer 42 is 10-20. In each composite insertion layer 42, the thickness of the N-B z Ga 1-z N layer 421 is 5-10nm, and is exemplarily 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm, 8nm, 8.5nm, 9nm or 9.5nm, but is not limited thereto. The doping element of the N-B z Ga 1-z N layer 421 is Si, and the doping concentration is 8×10 17 -2×10 18 cm -3 . The N-Al w Ga 1-w N layer 432 is 20-40nm, and is exemplarily 23nm, 26nm, 29nm, 31nm, 33nm, 35nm, 37nm or 39nm, but is not limited thereto. The doping element of the N-Al w Ga 1-w N layer 422 is Si, and the doping concentration is 8×10 17 -3×10 18 cm -3 .

[0040] Specifically, the thickness of the first N-GaN layer 41 is 200-500 nm, and is exemplarily 225 nm, 250 nm, 275 nm, 300 nm, 350 nm, 380 nm, 410 nm, 430 nm, 445 nm, 470 nm or 490 nm, but is not limited thereto. The doping element of the first N-GaN layer 41 is Si, and the doping concentration is 3x1018cm-3. 18 -9x1018cm-3. 18 -3 The thickness of the second N-GaN layer 43 is 800-1500 nm, and is exemplarily 850 nm, 900 nm, 950 nm, 1000 nm, 1100 nm, 1230 nm, 1300 nm, 1350 nm or 1480 nm, but is not limited thereto. The doping element of the second N-GaN layer 43 is Si, and the doping concentration is 1x1018cm-3. 19 -5x1018cm-3. 19 -3

[0041] The substrate 1 can be a sapphire substrate, a silicon substrate, a silicon carbide substrate, an aluminum nitride substrate, but is not limited thereto.

[0042] The thickness of the U-GaN layer 3 is 300-800 nm, and is exemplarily 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm or 750 nm, but is not limited thereto.

[0043] The multi-quantum well layer 5 is a periodic structure, and the number of periods is 5-20. Each period includes an InGa a Ga 1-a N well layer and a GaN barrier layer, wherein a=0.1-0.35. The thickness of a single InGa a Ga 1-a N well layer is 2-5 nm, and the thickness of a single GaN barrier layer is 3-15 nm.

[0044] The electron blocking layer 6 is an AlGaN layer or an AlInGaN layer, but is not limited thereto. Preferably, in an embodiment of the present application, the electron blocking layer 6 is an Al b In c Ga 1-b-c N layer. Herein, a is 0.1-0.2, and b is 0.2-0.5. The thickness of the electron blocking layer 6 is 20-150 nm, and is exemplarily 50 nm, 80 nm, 110 nm, 125 nm or 140 nm, but is not limited thereto.

[0045] The doping element in the P-GaN layer 7 is Mg, but is not limited thereto. The doping concentration of Mg in the P-GaN layer 7 is 5x1019cm-3. 17 ​​​-1x10 20 cm -3 The thickness of the P-GaN layer 7 is 400-800 nm.

[0046] Correspondingly, referring to Figure 4 The application further discloses a preparation method of the anti-hydrolysis blue-green light LED epitaxial structure.

[0047] S1: providing a substrate;

[0048] S2: sequentially growing a buffer layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer and a P-GaN layer on the substrate;

[0049] Specifically, S2 comprises:

[0050] S21: growing a buffer layer on the substrate;

[0051] Specifically, S21 comprises:

[0052] S211: growing a BN layer on the substrate;

[0053] Specifically, in an embodiment of the application, the BN layer is grown by MOCVD, the growth temperature is 780-880 ℃, and the growth pressure is 20-200 torr.

[0054] S212: growing a B x Ga 1-x N layer on the BN layer;

[0055] Specifically, in an embodiment of the application, the B x Ga 1-x N layer is grown by MOCVD, the growth temperature is 1000-1100 ℃, and the growth pressure is 100-300 torr.

[0056] S213: growing an Al x Ga 1-x N layer on the B y Ga 1-y N layer;

[0057] Specifically, in an embodiment of the application, the Al y Ga 1-y N layer is grown by MOCVD, the growth temperature is 700-900 ℃, and the growth pressure is 50-200 torr.

[0058] S22: growing a U-GaN layer on the buffer layer;

[0059] Specifically, the U-GaN layer is grown in MOCVD at a growth temperature of 1100-1150℃ and a growth pressure of 100-500 torr.

[0060] S23: growing a N-GaN layer on the U-GaN layer;

[0061] Specifically, in one embodiment of the present application, the N-GaN layer is grown in MOCVD at a growth temperature of 1100-1150℃ and a growth pressure of 100-500 torr.

[0062] Preferably, in another embodiment of the present application, step S23 comprises:

[0063] S231: growing a first N-GaN layer on the U-GaN layer;

[0064] Specifically, in one embodiment of the present application, the N-GaN layer is grown in MOCVD at a growth temperature of 1100-1150℃ and a growth pressure of 100-300 torr.

[0065] S232: growing a N-B z Ga 1-z N layer;

[0066] Specifically, in one embodiment of the present application, the N-B z Ga 1-z N layer is grown in MOCVD at a growth temperature of 900-1000℃ and a growth pressure of 100-300 torr.

[0067] S233: growing a N-Al y Ga 1-y N layer;

[0068] Specifically, in one embodiment of the present application, the N-Al y Ga 1-y N layer is grown in MOCVD at a growth temperature of 900-1000℃ and a growth pressure of 100-300 torr.

[0069] S234: periodically repeating steps S232-S233 until a composite insertion layer is obtained.

[0070] S24: growing a multiple quantum well layer on the N-GaN layer;

[0071] Specifically, in one embodiment of the present application, In a Ga 1-a N potential well layers and GaN potential barrier layers are periodically grown in MOCVD to form the multiple quantum well layer. In this embodiment, the In a Ga 1-aThe growth temperature of the N-type well layer is 700-800℃, and the growth pressure is 100-500 torr; the growth temperature of the GaN-type barrier layer is 800-900℃, and the growth pressure is 100-500 torr.

[0072] S25: Growth of an electron blocking layer on a multi-quantum-well layer;

[0073] Specifically, in one embodiment of the present invention, Al is grown in MOCVD. b In c Ga 1-b-c The N-layer serves as an electron blocking layer. The electron blocking layer is grown at a temperature of 900-1000℃ and a growth pressure of 100-500 torr.

[0074] S26: Grow a P-GaN layer on the electron blocking layer;

[0075] Specifically, in one embodiment of the present invention, a P-GaN layer is grown in MOCVD at a growth temperature of 800-1000℃ and a growth pressure of 100-300 torr.

[0076] The present invention will be further described below with reference to specific embodiments:

[0077] Example 1

[0078] This embodiment provides an epitaxial structure for hydrolysis-resistant blue-green LEDs, referenced... Figure 1 , Figure 2 It includes a substrate 1 and a buffer layer 2, a U-GaN layer 3, an N-GaN layer 4, a multiple quantum well layer 5, an electron blocking layer 6 and a P-GaN layer 7 sequentially disposed on the substrate 1.

[0079] Wherein, substrate 1 is a sapphire substrate, and buffer layer 2 is composed of sequentially stacked BN layer 21 and B x Ga 1-x Layer N, 22 (x = 0.12) and Al y Ga 1-y N layer 23 (0.15); BN layer 21 has a thickness of 8nm, B x Ga 1-x The thickness of layer N22 is 13nm, Al y Ga 1-y The thickness of layer N23 is 19nm.

[0080] The thickness of U-GaN layer 3 is 700 nm. The Si doping concentration in N-GaN layer 4 is 8 × 10⁻⁶. 18 cm -3 Its thickness is 2 μm. The multi-quantum well layer 5 is a periodic structure with 12 periods. Each period includes In. a Ga1-a N well layer (a = 0.25) and GaN barrier layer. Single In a Ga 1-a The thickness of the N well layer is 3.5 nm and the thickness of the single GaN barrier layer is 11.5 nm. The electron blocking layer 6 is Al b In c Ga 1-b-c N layer (a = 0.14, b = 0.35) with a thickness of 120 nm. The doped element of the P-GaN layer 7 is Mg and the doping concentration is 5 x 1018 cm-3 with a thickness of 650 nm. 18 cm -3 .

[0081] The method for preparing the anti-hydrolysis blue-green light LED epitaxial structure in the embodiment comprises the following steps:

[0082] (1) providing a substrate;

[0083] (2) growing a BN layer on the substrate;

[0084] Specifically, the BN layer is grown by MOCVD, and the growth temperature is 800°C and the growth pressure is 120 torr.

[0085] (3) growing a B x Ga 1-x N layer on the BN layer;

[0086] Specifically, the B x Ga 1-x N layer is grown by MOCVD, and the growth temperature is 1050°C and the growth pressure is 200 torr.

[0087] (4) growing an Al x Ga 1-x N layer on the B y Ga 1-y N layer;

[0088] Specifically, in an embodiment of the present application, the Al y Ga 1-y N layer is grown by MOCVD, and the growth temperature is 820°C and the growth pressure is 100 torr.

[0089] (5) growing a U-GaN layer on the buffer layer;

[0090] Specifically, the U-GaN layer is grown by MOCVD, and the growth temperature is 1120°C and the growth pressure is 300 torr.

[0091] (6) growing an N-GaN layer on the U-GaN layer;

[0092] Specifically, the N-GaN layer was grown using MOCVD at a growth temperature of 1120℃ and a growth pressure of 200 torr.

[0093] (7) Growth of multiple quantum well layers on N-GaN layers;

[0094] Specifically, in MOCVD, In... a Ga 1-a An N-type potential well layer and a GaN-type barrier layer are used to form a multi-quantum well layer. In... a Ga 1-a The growth temperature of the N-type well layer is 750℃ and the growth pressure is 300 torr; the growth temperature of the GaN-type barrier layer is 870℃ and the growth pressure is 300 torr.

[0095] The fabrication method for each quantum well layer is as follows:

[0096] (6) Grow an electron blocking layer on a multi-quantum-well layer;

[0097] Specifically, growing Al in MOCVD b In c Ga 1-b-c The N-layer serves as an electron blocking layer. The electron blocking layer is grown at a temperature of 950°C and a growth pressure of 300 torr.

[0098] (7) Grow a P-GaN layer on the electron blocking layer;

[0099] Specifically, the P-GaN layer was grown using MOCVD at a growth temperature of 850℃ and a growth pressure of 200 torr.

[0100] Example 2

[0101] This embodiment provides an epitaxial structure for hydrolysis-resistant blue-green LEDs, referenced... Figure 1 , Figure 2 , Figure 3 It includes a substrate 1 and a buffer layer 2, a U-GaN layer 3, an N-GaN layer 4, a multiple quantum well layer 5, an electron blocking layer 6 and a P-GaN layer 7 sequentially disposed on the substrate 1.

[0102] Wherein, substrate 1 is a sapphire substrate, and buffer layer 2 is composed of sequentially stacked BN layer 21 and B x Ga 1-x N layer 22 (x is 0.12) and Al y Ga 1-y N layer 23 (0.15); BN layer 21 has a thickness of 8nm, B x Ga 1-x The thickness of layer N22 is 13nm, Al y Ga 1-yThe thickness of the N-layer 23 is 19 nm. The thickness of the U-GaN layer 3 is 700 nm.

[0103] The N-GaN layer 4 consists of a first N-GaN layer 41, a composite insertion layer 42, and a second N-GaN layer 43, which are stacked sequentially. The first N-GaN layer 41 has a thickness of 350 nm and is doped with Si at a concentration of 8 × 10⁻⁶. 18 cm -3 The composite insert layer 42 is for NB. z Ga 1-z N (z = 0.13) layer 421 and N-Al w Ga 1-w A periodic superlattice structure consisting of N (w = 0.15) layers 422, with a period number of 12, wherein in each composite insertion layer 42, NB z Ga 1-z The thickness of the N-layer 421 is 6.5nm, NB z Ga 1-z The N-layer 421 is doped with Si, and the doping concentration is 1×10⁻⁶. 18 cm -3 N-Al w Ga 1-w The thickness of the N-layer 432 is 22nm, N-Al w Ga 1-w The N-layer 422 is doped with Si, and the doping concentration is 1.5 × 10⁻⁶. 18 cm -3 The second N-GaN layer 43 has a thickness of 1380 nm, and the doping element of the second N-GaN layer 43 is Si, with a doping concentration of 8 × 10⁻⁶. 18 cm -3 .

[0104] Among them, the multi-quantum well layer 5 is a periodic structure with 12 periods. Each period includes In... a Ga 1-a N-type well layer (a = 0.25) and GaN barrier layer. Single In a Ga 1-a The thickness of the N-well layer is 3.5 nm, and the thickness of a single GaN barrier layer is 11.5 nm. Electron blocking layer 6 is made of Al. b In c Ga 1-b-c The N-layer (a = 0.14, b = 0.35) has a thickness of 120 nm. The P-GaN layer 7 is doped with Mg at a concentration of 5 × 10⁻⁶. 18 cm -3 The thickness is 650nm.

[0105] The method for preparing the anti-hydrolysis epitaxial structure for blue-green LED in the embodiment comprises the following steps:

[0106] (1) providing a substrate;

[0107] (2) growing a BN layer on the substrate;

[0108] Specifically, the BN layer is grown by MOCVD, and the growth temperature is 800 ℃ and the growth pressure is 120 torr.

[0109] (3) growing a B x Ga 1-x N layer on the BN layer;

[0110] Specifically, the B x Ga 1-x N layer is grown by MOCVD, and the growth temperature is 1050 ℃ and the growth pressure is 200 torr.

[0111] (4) growing an Al x Ga 1-x N layer on the B y Ga 1-y N layer;

[0112] Specifically, in an embodiment of the present application, the Al y Ga 1-y N layer is grown by MOCVD, and the growth temperature is 820 ℃ and the growth pressure is 100 torr.

[0113] (5) growing a U-GaN layer on the buffer layer;

[0114] Specifically, the U-GaN layer is grown by MOCVD, and the growth temperature is 1120 ℃ and the growth pressure is 300 torr.

[0115] (6) growing a first N-GaN layer on the U-GaN layer;

[0116] Specifically, the first N-GaN layer is grown by MOCVD, and the growth temperature is 1120 ℃ and the growth pressure is 200 torr.

[0117] (7) growing an N-B z Ga 1-z N layer;

[0118] Specifically, the N-B z Ga 1-z N layer is grown by MOCVD, and the growth temperature is 960 ℃ and the growth pressure is 200 torr.

[0119] (8) growing an N-Al y Ga 1-y N layer;

[0120] Specifically, the N-Al y Ga 1-y N layer is grown by MOCVD at a growth temperature of 960℃ and a growth pressure of 200 torr.

[0121] (9) repeating steps (7)-(8) periodically until a composite insertion layer is obtained.

[0122] (10) growing a second N-GaN layer on the composite insertion layer;

[0123] Specifically, the second N-GaN layer is grown by MOCVD at a growth temperature of 1120℃ and a growth pressure of 200 torr.

[0124] (11) growing a multi-quantum well layer on the second N-GaN layer;

[0125] Specifically, the In a Ga 1-a N potential well layer and the GaN potential barrier layer are periodically grown by MOCVD to form the multi-quantum well layer. The growth temperature of the In a Ga 1-a N potential well layer is 750℃ and the growth pressure is 300 torr, and the growth temperature of the GaN potential barrier layer is 870℃ and the growth pressure is 300 torr.

[0126] The preparation method of each quantum well layer is as follows:

[0127] (12) growing an electron blocking layer on the multi-quantum well layer;

[0128] Specifically, the Al b In c Ga 1-b-c N layer is grown by MOCVD at a growth temperature of 950℃ and a growth pressure of 300 torr.

[0129] (13) growing a P-GaN layer on the electron blocking layer;

[0130] Specifically, the P-GaN layer is grown by MOCVD at a growth temperature of 850℃ and a growth pressure of 200 torr.

[0131] Embodiment 3

[0132] This embodiment provides an anti-hydrolysis blue-green LED epitaxial structure, which refers to Figure 1 、 Figure 2 、 Figure 3It includes a substrate 1 and a buffer layer 2, a U-GaN layer 3, an N-GaN layer 4, a multiple quantum well layer 5, an electron blocking layer 6 and a P-GaN layer 7 sequentially disposed on the substrate 1.

[0133] Wherein, substrate 1 is a sapphire substrate, and buffer layer 2 is composed of sequentially stacked BN layer 21 and B x Ga 1-x Layer N, 22 (x = 0.12) and Al y Ga 1-y N layer 23 (0.15); BN layer 21 has a thickness of 8nm, B x Ga 1-x The thickness of layer N22 is 13nm, Al y Ga 1-y The thickness of the N-layer 23 is 19 nm. The thickness of the U-GaN layer 3 is 700 nm.

[0134] The N-GaN layer 4 consists of a first N-GaN layer 41, a composite insertion layer 42, and a second N-GaN layer 43, which are stacked sequentially. The first N-GaN layer 41 has a thickness of 350 nm and is doped with Si at a concentration of 8 × 10⁻⁶. 18 cm -3 The composite insert layer 42 is for NB. z Ga 1-z N (z = 0.13) layer 421 and N-Al w Ga 1-w A periodic superlattice structure consisting of N (w = 0.15) layers 422, with a period number of 12, wherein in each composite insertion layer 42, NB z Ga 1-z The thickness of the N-layer 421 is 6.5nm, NB z Ga 1-z The N-layer 421 is doped with Si, and the doping concentration is 1×10⁻⁶. 18 cm -3 N-Al w Ga 1-w The thickness of the N-layer 432 is 22nm, N-Al w Ga 1-w The N-layer 422 is doped with Si, and the doping concentration is 1.5 × 10⁻⁶. 18 cm -3 The second N-GaN layer 43 has a thickness of 1380 nm, and the doping element of the second N-GaN layer 43 is Si, with a doping concentration of 3 × 10⁻⁶. 19 cm -3 .

[0135] Among them, the multi-quantum well layer 5 is a periodic structure with 12 periods. Each period includes In...a Ga 1-a N well layer (a = 0.25) and GaN barrier layer. Single In a Ga 1-a N well layer is 3.5 nm, and single GaN barrier layer is 11.5 nm. The electron blocking layer 6 is Al b In c Ga 1-b-c N layer (a = 0.14, b = 0.35) with a thickness of 120 nm. The doped element of the P-GaN layer 7 is Mg, and the doping concentration is 5 x 10 18 cm -3 with a thickness of 650 nm.

[0136] The method for preparing the anti-hydrolysis blue-green LED epitaxial structure in the embodiment comprises the following steps:

[0137] (1) providing a substrate;

[0138] (2) growing a BN layer on the substrate;

[0139] Specifically, the BN layer is grown by MOCVD, and the growth temperature is 800°C, and the growth pressure is 120 torr.

[0140] (3) growing a B x Ga 1-x N layer on the BN layer;

[0141] Specifically, the B x Ga 1-x N layer is grown by MOCVD, and the growth temperature is 1050°C, and the growth pressure is 200 torr.

[0142] (4) growing an Al x Ga 1-x N layer on the B y Ga 1-y N layer;

[0143] Specifically, in an embodiment of the present application, the Al y Ga 1-y N layer is grown by MOCVD, and the growth temperature is 820°C, and the growth pressure is 100 torr.

[0144] (5) growing a U-GaN layer on the buffer layer;

[0145] Specifically, the U-GaN layer is grown by MOCVD, and the growth temperature is 1120°C, and the growth pressure is 300 torr.

[0146] (6) growing a first N-GaN layer on the U-GaN layer;

[0147] Specifically, the first N-GaN layer is grown by MOCVD at a growth temperature of 1120 °C and a growth pressure of 200 torr.

[0148] (7) growing N-B z Ga 1-z N layer;

[0149] Specifically, the N-B z Ga 1-z N layer is grown by MOCVD at a growth temperature of 960 °C and a growth pressure of 200 torr.

[0150] (8) growing N-Al y Ga 1-y N layer;

[0151] Specifically, the N-Al y Ga 1-y N layer is grown by MOCVD at a growth temperature of 960 °C and a growth pressure of 200 torr.

[0152] (9) repeating steps (7) - (8) periodically until a composite insertion layer is obtained.

[0153] (10) growing a second N-GaN layer on the composite insertion layer;

[0154] Specifically, the second N-GaN layer is grown by MOCVD at a growth temperature of 1120 °C and a growth pressure of 200 torr.

[0155] (11) growing a multiple quantum well layer on the second N-GaN layer;

[0156] Specifically, the In a Ga 1-a N potential well layer and the GaN potential barrier layer are periodically grown by MOCVD to form the multiple quantum well layer. The growth temperature of the In a Ga 1-a N potential well layer is 750 °C and the growth pressure is 300 torr; the growth temperature of the GaN potential barrier layer is 870 °C and the growth pressure is 300 torr.

[0157] The preparation method of each quantum well layer is as follows:

[0158] (12) growing an electron blocking layer on the multiple quantum well layer;

[0159] Specifically, the Al b In c Ga 1-b-c N layer is grown by MOCVD as the electron blocking layer. The growth temperature of the electron blocking layer is 950 °C and the growth pressure is 300 torr.

[0160] (13) growing a P-GaN layer on the electron blocking layer;

[0161] Specifically, the P-GaN layer is grown by MOCVD, the growth temperature is 850℃, and the growth pressure is 200 torr.

[0162] Comparative Example 1

[0163] This comparative example provides an epitaxial structure for blue-green light LED, which is different from Example 1 in that the buffer layer 2 is an AlN layer with a thickness of 40 nm, which is made by PVD method.

[0164] Comparative Example 2

[0165] This comparative example provides an epitaxial structure for blue-green light LED, which is different from Example 1 in that the buffer layer 2 does not contain the BN layer 21, and accordingly, the step of preparing the layer is not included in the preparation method.

[0166] Comparative Example 3

[0167] This comparative example provides an epitaxial structure for blue-green light LED, which is different from Example 1 in that the buffer layer 2 does not contain the BN layer 21, and accordingly, the step of preparing the layer is not included in the preparation method. x Ga 1-x N layer 22, and accordingly, the step of preparing the layer is not included in the preparation method.

[0168] The epitaxial structures for blue-green light LED obtained in Examples 1-3 and Comparative Examples 1-3 are tested, and the specific test method is as follows:

[0169] The epitaxial structures prepared in each example and comparative example are prepared into a positive LED chip according to the conventional method (see document 201810417428.4), and then measured according to the existing equipment (CN202010143107.7), specifically, the test temperature is 85℃, and the humidity is 90%RH; every 5h is taken out, observed under a high-power microscope, if there is corrosion, the time of the previous one is taken as the maximum hydrolysis time; if there is no corrosion, put it into the equipment and continue to test.

[0170] The specific results are shown in the following table:

[0171]

[0172]

[0173] As can be seen from the table, when the conventional quantum well layer (Comparative Example 1) is changed to the quantum well layer structure in the present application, the luminous efficiency and wavelength uniformity are both significantly improved. In addition, as can be seen from the comparison between Example 1 and Comparative Examples 2-4, when the quantum well layer structure in the present application is changed, it is difficult to effectively improve the luminous efficiency and wavelength uniformity.

[0174] The above describes the preferred embodiments of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which are also considered within the scope of protection of the present application.

Claims

1. An epitaxial structure for a hydrolysis-resistant blue-green LED, comprising a substrate and, sequentially on the substrate, a buffer layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer, and a P-GaN layer; characterized in that, The buffer layer includes BN layers, B x Ga 1-x N layers and Al y Ga 1-y N layers stacked in sequence, wherein x is 0.1-0.2 and y is 0.1-0.

2. The N-GaN layer comprises a first N-GaN layer, a composite insertion layer and a second N-GaN layer which are stacked in sequence; the composite insertion layer is N-B z Ga 1-z N layer and a N-Al w Ga 1-w N layer, and the period number of the periodic superlattice structure is ≥2, wherein z is 0.1-0.2 and w is 0.1-0.

2. The first N-GaN layer has a thickness of 200-500 nm, and the second N-GaN layer has a thickness of 800-1500 nm; The doping element of the first N-GaN layer is Si, and the doping concentration is 3x10 18 -9x10 18 cm -3 -5; the doping element of the second N-GaN layer is Si, and the doping concentration is 1x10 19 -5x10 19 cm -3 ; The N-B z Ga 1-z The doping element of the N layer is Si, and the doping concentration is 8×10 17 -2×10 18 cm -3 ; the N-Al w Ga 1-w The doping element of the N layer is Si, and the doping concentration is 8×10 17 -3×10 18 cm -3 .

2. The anti-hydrolysis epitaxial structure for blue-green LED of claim 1, wherein, The BN layer has a thickness of 5-10 nm, the B x Ga 1-x The GaN layer has a thickness of 10-20 nm, the Al y Ga 1-y The GaN layer has a thickness of 10-20 nm.

3. The anti-hydrolysis epitaxial structure for blue-green LED of claim 1, wherein, The composite insertion layer has a period number of 10-20; N-B z Ga 1-z N layer has a thickness of 5-10 nm, N-Al w Ga 1-w N layer has a thickness of 20-40 nm.

4. An anti-hydrolysis blue-green LED epitaxial structure for preparing the anti-hydrolysis blue-green LED epitaxial structure according to any one of claims 1-3, characterized in that, The method comprises: A substrate is provided, and a buffer layer, a U-GaN layer, an N-GaN layer, a multi-quantum well layer, an electron blocking layer and a P-GaN layer are sequentially grown on the substrate; The buffer layer comprises BN layer, B x Ga 1-x N layer and Al y Ga 1-y N layer, wherein x is 0.1-0.2 and y is 0.1-0.

2. The N-GaN layer comprises a first N-GaN layer, a composite insertion layer and a second N-GaN layer which are stacked in sequence; wherein the composite insertion layer is N-B z Ga 1-z N layer and N-Al w Ga 1-w N layer, and the period number of the periodic superlattice structure is ≥2, wherein z is 0.1-0.2 and w is 0.1-0.

2. The growth temperature of the first N-GaN layer and the second N-GaN layer is 1050-1150 ℃, and the growth pressure is 100-300 torr; The growth temperature of the composite insertion layer is 900-1000 ℃, and the growth pressure is 100-300 torr.

5. The method of producing an epitaxial structure for a water hydrolysis resistant blue-green LED according to claim 4, wherein The growth temperature of the BN layer is 780-880 ℃, and the growth pressure is 20-200 torr; The B x Ga 1-x The growth temperature of the N layer is 1000-1100℃, and the growth pressure is 100-300 torr; The Al y Ga 1-y The growth temperature of the GaN layer is 700-900 °C, and the growth pressure is 50-200 torr.

6. A hydrolysis resistant blue-green LED, characterized in that, The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises:

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