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

Abstract

The application discloses an epitaxial wafer of a light emitting diode, a preparation method of the epitaxial wafer and the light emitting diode, and relates to the field of semiconductor photoelectric devices. The epitaxial wafer of the light emitting diode comprises a substrate, a buffer layer, a non-doped GaN layer, an N-type GaN layer, an active layer, an electron blocking layer and a P-type GaN layer arranged on the substrate in sequence; the electron blocking layer comprises an Mn / Zn co-doped Al x In y Ga 1‑x‑y N layer. By implementing the application, the light emitting efficiency of the light emitting diode can be improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor optoelectronic devices, and more particularly to a light-emitting diode epitaxial wafer and its fabrication method, and a light-emitting diode. Background Technology

[0002] Traditional light-emitting diode (LED) epitaxial wafers consist of a substrate and, sequentially grown on the substrate, a buffer layer, an undoped GaN layer, an N-type GaN layer, an active layer, an electron blocking layer, and a P-type GaN layer. Due to the high electron mobility, electrons easily overflow from the active layer to the P-type GaN layer and recombine with holes, thus reducing luminous efficiency. This problem is more pronounced at high current densities. Therefore, an electron blocking layer is typically designed into the epitaxial layer to block electrons. Existing electron blocking layers are often made of AlGaN material with a high Al content. This causes a large number of dislocations to be generated during epitaxial growth, affecting the crystal quality of the P-type GaN layer and leading to severe non-radiative recombination centers. On the other hand, while blocking electrons, the high Al content electron blocking layer, due to its high potential barrier and the effects of spontaneous polarization and piezoelectric polarization, also hinders the injection of holes from the P-type GaN layer into the active layer, affecting luminous efficiency. Summary of the Invention

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

[0004] Another technical problem that this invention aims to solve is to provide a light-emitting diode with high luminous efficiency.

[0005] To address the aforementioned problems, this invention discloses a light-emitting diode epitaxial wafer, comprising a substrate and a buffer layer, an undoped GaN layer, an N-type GaN layer, an active layer, an electron blocking layer, and a P-type GaN layer sequentially disposed on the substrate; the electron blocking layer comprises Mn / Zn co-doped Al. x In y Ga 1-x-y N layers.

[0006] As an improvement to the above technical solution, the Mn / Zn co-doped Al x In y Ga 1-x-y The Mn doping concentration in the N layer is 1×10⁻⁶. 18 cm -3 -1×10 20 cm -3 The Zn doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 20 cm -3, 0.2≤x≤0.8, 0≤y≤0.2.

[0007] As an improvement to the above technical solution, the Mn / Zn co-doped Al x In y Ga 1-x-y The thickness of the N layer is 10nm-100nm.

[0008] As an improvement to the above technical solution, the electron blocking layer further includes Mg-doped Al. a In b Ga 1-a-b N-layer, the Mg-doped Al a In b Ga 1-a-b The N-layer is disposed on the Mn / Zn co-doped Al. x In y Ga 1-x-y Above the Nth floor.

[0009] As an improvement to the above technical solution, the Mg-doped Al a In b Ga 1-a-b The Mg doping concentration in the N layer is 1×10⁻⁶. 17 cm -3 -1×10 19 cm -3 0.1≤a≤0.5, 0≤b≤0.1, the Mg doped with Al a In b Ga 1-a-b The thickness of the N layer is 5nm-20nm.

[0010] As an improvement to the above technical solution, the Mg-doped Al a In b Ga 1-a-b The lattice constant of the N-layer is intermediate between that of the Mn / Zn co-doped Al. x In y Ga 1-x-y The distance between the N-layer and the P-type GaN layer gradually increases along the direction of epitaxial growth.

[0011] Accordingly, the present invention also discloses a method for preparing a light-emitting diode epitaxial wafer, which includes:

[0012] A substrate is provided on which a buffer layer, an undoped GaN layer, an N-type GaN layer, an active layer, an electron blocking layer, and a P-type GaN layer are sequentially grown; the electron blocking layer comprises Mn / Zn co-doped Al. x In y Ga 1-x-y N layers.

[0013] As an improvement to the above technical solution, the Mn / Zn co-doped Al x In y Ga 1-x-y The growth temperature of the N layer is 850℃-1050℃, and the growth pressure is 50 torr-200 torr.

[0014] As an improvement to the above technical solution, the electron blocking layer further includes Mg-doped Al. a In b Ga 1-a-b N-layer, the Mg-doped Al a In b Ga 1-a-b The N-layer is disposed on the Mn / Zn co-doped Al. x In y Ga 1-x-y Above the N layer, the Mg-doped Al a In b Ga 1-a-b The growth temperature of the N layer is 800℃-1000℃, and the growth pressure is 50 torr-150 torr.

[0015] Accordingly, the present invention also discloses a light-emitting diode, which includes the above-mentioned light-emitting diode epitaxial wafer.

[0016] Implementing this invention has the following beneficial effects:

[0017] 1. In the epitaxial wafer of the light-emitting diode of the present invention, the electron blocking layer comprises Mn / Zn co-doped Al x In y Ga 1-x-y N layers. First, Mn / Zn co-doped Al. x In y Ga 1-x-y Mn in the N-layer exhibits spin polarization, which reduces hole scattering loss and increases hole mobility. Furthermore, the magnetic exchange effect of Mn provides additional transport paths for hole conduction, improving hole conduction performance while maintaining strong electron blocking ability, thus enhancing luminous efficiency. Secondly, doping with Zn can improve both hole mobility and conduction performance. Additionally, the hybrid effects between Zn and Mn can neutralize the localization effects caused by Mn doping. Finally, Mn / Zn co-doped Al... x In y Ga 1-x-y The N-layer is connected to the active layer using a material similar to that of the active layer. This reduces lattice mismatch with the active layer, improves lattice quality, and reduces band spikes caused by excessive band changes between the traditional electron blocking layer and the active layer, thus avoiding interference with hole injection and improving luminous efficiency.

[0018] 2. In the light-emitting diode epitaxial wafer of the present invention, the electron blocking layer further includes Mg-doped Al. a In b Ga 1-a-b In the N-layer, appropriate Mg doping can hinder dislocation slip, reduce the internal defect density of the crystal, improve lattice quality, and increase luminescence efficiency.

[0019] 3. In the epitaxial wafer of the light-emitting diode of the present invention, Mg is doped with Al. a In b Ga 1-a-b The lattice constant of the N-layer is intermediate between that of Mn / Zn co-doped Al. x In y Ga 1-x-y The distance between the N-layer and the P-type GaN layer gradually increases along the epitaxial growth direction, resulting in a smooth transition of energy levels between the electron blocking layer and the P-type GaN layer, which improves lattice quality and luminescence efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a light-emitting diode epitaxial wafer in one embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the electron blocking layer in one embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the electron blocking layer in another embodiment of the present invention;

[0023] Figure 4 This is a flowchart of a method for preparing an epitaxial wafer for a light-emitting diode according to an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0025] refer to Figure 1 and Figure 2 This invention discloses a light-emitting diode epitaxial wafer, comprising a substrate 1 and a buffer layer 2, an undoped GaN layer 3, an N-type GaN layer 4, an active layer 5, an electron blocking layer 6, and a P-type GaN layer 7 sequentially disposed on the substrate 1; wherein the electron blocking layer 6 comprises Mn / Zn co-doped Al x In y Ga 1-x-y N-layer 61. First, Mn / Zn co-doped Al x In y Ga 1-x-yIn the N-layer 61, Mn exhibits spin polarization, which reduces hole scattering loss and increases hole mobility. Furthermore, the magnetic exchange effect of Mn provides additional transport paths for hole conduction, improving hole conduction performance while maintaining strong electron blocking ability, thus enhancing luminous efficiency. Secondly, doping with Zn not only improves hole mobility and conduction performance but also generates hybrid effects between Zn and Mn, neutralizing the localization effects caused by Mn doping. Finally, Mn / Zn co-doped Al... x In y Ga 1-x-y The N layer 61 is connected to the active layer 5 and uses a similar material to the active layer 5. This can reduce the lattice mismatch with the active layer 5, improve the lattice quality, and reduce the band spikes caused by excessive band changes between the traditional electron blocking layer and the active layer, thus avoiding affecting hole injection and improving luminous efficiency.

[0026] Specifically, Mn / Zn co-doped Al x In y Ga 1-x-y The Mn doping concentration in N-layer 61 is 1×10⁻⁶. 18 cm -3 -5×10 20 cm -3 If the doping concentration of Mn is < 1 × 10 18 cm -3 This is insufficient to significantly improve hole mobility and conduction performance; if the Mn doping concentration is > 5 × 10⁻⁶, it will not significantly improve hole mobility and conduction performance. 20 cm -3 This can lead to a localization effect, which in turn reduces hole mobility and conductivity. Preferably, the Mn doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 20 cm -3 An example is 2×10 18 cm -3 4×10 18 cm -3 6×10 18 cm -3 8×10 18 cm -3 1×10 19 cm -3 2×10 19 cm -3 4×10 19 cm -3 6×10 19 cm -3 Or 8×10 19 cm -3 However, it is not limited to this.

[0027] Specifically, the Zn doping concentration is 1×10⁻⁶. 18 cm -3 -5×10 20 cm -3 If the Zn doping concentration is < 1 × 10 18 cm -3 It is difficult to effectively improve the hole mobility and conduction performance; if the Zn doping concentration is >5×10 20 cm -3 This would introduce too many defects. Preferably, the Zn doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 20 cm -3 An example is 2×10 18 cm -3 4×10 18 cm -3 6×10 18 cm -3 8×10 18 cm -3 1×10 19 cm -3 2×10 19 cm -3 4×10 19 cm -3 6×10 19 cm -3 Or 8×10 19 cm -3 However, it is not limited to this.

[0028] Specifically, 0.2 ≤ x ≤ 0.8. Within this range, the Al composition effectively limits electron overflow and reduces hole blockage. Examples of x include 0.3, 0.4, 0.5, 0.6, or 0.7, but it is not limited to these.

[0029] Specifically, 0 ≤ y ≤ 0.2. The In composition within this range reduces lattice mismatch between the active layer 5 and the p-type GaN layer 7. Examples of y values ​​are 0.12, 0.14, 0.16, or 0.18, but are not limited to these.

[0030] Specifically, Mn / Zn co-doped Al x In y Ga 1-x-yThe thickness of the N-layer 61 is 10nm-120nm. If the thickness is less than 10nm, it cannot effectively block electrons; if the thickness is greater than 120nm, it will introduce too many defects. Preferably, the thickness is 10nm-100nm, with examples of 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, or 90nm, but not limited to these.

[0031] Preferably, in another embodiment of the invention, reference is made to... Figure 3 Electron blocking layer 6 also includes Mg-doped Al a In b Ga 1-a-b N-layer 62, Mg-doped Al a In b Ga 1-a-b N-layer 62 is located in Mn / Zn co-doped Al. x In y Ga 1-x-y Above layer 61 (N). Appropriate Mg doping can hinder dislocation slip, reduce the defect density inside the crystal, improve lattice quality, and increase luminescence efficiency.

[0032] Specifically, the Mg doping concentration is 1×10⁻⁶. 17 cm -3 -5×10 19 cm -3 If the doping concentration is <1×10 17 cm -3 It cannot effectively hinder dislocation slip; if the doping concentration is >5×10 19 cm -3 This leads to a large number of magnesium and nitrogen vacancies, which can cause lattice distortion. Furthermore, excessively high Mg doping concentrations can introduce planar dislocations such as stacking faults and heterostructure interface defects, affecting luminescence efficiency. Preferably, the Mg doping concentration is 1 × 10⁻⁶. 17 cm -3 -1×10 19 cm -3 An example is 3×10 17 cm -3 5×10 17 cm -3 7×10 17 cm -3 1×10 18 cm -3 3×10 18 cm -3 5×10 18 cm -3 7×10 17 cm -3 Or 9×10 17 cm-3 However, it is not limited to this.

[0033] Specifically, 0.1 ≤ a ≤ 0.55, 0 ≤ b ≤ 0.12, with Al and In compositions within this range, can reduce the lattice mismatch between the electron blocking layer 6 and the active layer 5 and the p-type GaN layer 7. Preferably, 0.1 ≤ a ≤ 0.5, 0 ≤ b ≤ 0.1, and exemplary cases, a is 0.2, 0.3, or 0.4, and b is 0.02, 0.04, 0.06, or 0.08, but are not limited thereto.

[0034] Specifically, Mg doped with Al a In b Ga 1-a-b The thickness of the N-layer 62 is 5nm-25nm. If the thickness is less than 5nm, it is difficult to effectively reduce lattice mismatch; if the thickness is greater than 25nm, it will introduce too many defects. Preferably, the thickness is 5nm-20nm, with 8nm, 10nm, 12nm, 14nm, 16nm or 18nm being exemplary, but not limited to these.

[0035] Further preferred, Mg-doped Al a In b Ga 1-a-b The lattice constant of N-layer 62 is intermediate between that of Mn / Zn co-doped Al. x In y Ga 1-x-y Between the N-layer 61 and the P-type GaN layer 7, the energy level gradually increases along the epitaxial growth direction, where y is 0. This configuration allows for a smooth energy level transition between the electron blocking layer 6 and the P-type GaN layer 7, improving lattice quality and luminous efficiency.

[0036] The substrate 1 can be a sapphire substrate, a silicon substrate, or a silicon carbide substrate, but is not limited to these. A sapphire substrate is preferred.

[0037] The buffer layer 2 can be an AlN layer and / or an AlGaN layer, and the thickness of the buffer layer 2 is 20nm-100nm, with exemplary values ​​of 25nm, 30nm, 35nm, 40nm, 50nm, 70nm or 85nm, but not limited thereto.

[0038] The thickness of the undoped GaN layer 3 is 1μm-1.7μm.

[0039] The doping element of the N-type GaN layer 4 is Si, but it is not limited to Si. The doping concentration of the N-type GaN layer 4 is 5 × 10⁻⁶. 17 cm -3 -1×10 19 cm -3 The thickness is 1μm-3μm.

[0040] The active layer 5 consists of alternating stacked InGaN quantum well layers and GaN quantum barrier layers, with a stacking period of 3-15. The thickness of a single InGaN quantum well layer is 2nm-4nm, and the thickness of a single GaN quantum barrier layer is 8nm-12nm.

[0041] The doping element in the p-type GaN layer 7 is Mg, but it is not limited to this. The doping concentration of Mg in the p-type GaN layer 7 is 5 × 10⁻⁶. 18 cm -3 -5×10 21 cm -3 The thickness of the p-type GaN layer 7 is 15nm-20nm.

[0042] Accordingly, refer to Figure 4 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 includes the following steps:

[0043] S100: Provides a substrate;

[0044] S200: A buffer layer is grown on the substrate;

[0045] Specifically, an AlGaN layer grown by MOCVD or PVD can be used as a buffer layer, but the method is not limited to these. Preferably, the AlGaN layer is grown by MOCVD at a growth temperature of 500℃-700℃ and a growth pressure of 200 torr-400 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source; H2 and N2 are used as carrier gases; TMAl is introduced as the Al source; and TMGa is introduced as the Ga source.

[0046] S300: An undoped GaN layer is grown on the buffer layer;

[0047] Specifically, undoped GaN layers were grown in MOCVD at a temperature of 1000℃-1250℃ and a pressure of 100 torr-300 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source; H2 and N2 were used as carrier gases, and TMGa was introduced as the Ga source.

[0048] S400: An N-type GaN layer is grown on an undoped GaN layer;

[0049] Specifically, an N-type GaN layer is grown in MOCVD at a temperature of 1000℃-1200℃ and a pressure of 100 torr-500 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source, and SiH4 is introduced as the N-type doping source; H2 and N2 are used as carrier gases, and TMGa is introduced as the Ga source.

[0050] S500: An active layer is grown on an N-type GaN layer;

[0051] Specifically, InGaN quantum well layers and GaN quantum barrier layers are periodically grown in MOCVD to form active layers. The InGaN quantum well layer is grown at a temperature of 760℃-800℃ and a growth pressure of 150 torr-250 torr. During growth, NH3 is introduced as the N source, N2 as the carrier gas, TEGa as the Ga source, and TMIn as the In source in the MOCVD reaction chamber. The GaN quantum barrier layer is grown at a temperature of 860℃-900℃ and a growth pressure of 150 torr-250 torr. During growth, NH3 is introduced as the N source, H2 and N2 as the carrier gases, and TEGa as the Ga source in the MOCVD reaction chamber.

[0052] S600: An electron blocking layer is grown on the active layer;

[0053] Specifically, in one embodiment of the present invention, S600 includes:

[0054] S610: Mn / Zn co-doped Al is grown on the active layer. x In y Ga 1-x-y N layers;

[0055] Specifically, Mn / Zn co-doped Al is grown in MOCVD. x In y Ga 1-x-y The N-layer was grown at a temperature of 850℃-1050℃ and a pressure of 50 torr-200 torr. During growth, NH3 was introduced as the N source, TMMn as the Mn source, DMZn as the Zn source, TEGa as the Ga source, TMI as the In source, and TMI as the Al source in the MOCVD reaction chamber, with N2 as the carrier gas.

[0056] S620: Al co-doped with Mn / Zn x In y Ga 1-x-y Mg-doped Al growing on N layer a In b Ga 1-a-b N layers;

[0057] Specifically, Mg-doped Al is grown in MOCVD. a In b Ga 1-a-bThe N-layer was grown at a temperature of 800℃-1000℃ and a pressure of 50 torr-150 torr. During growth, NH3 was introduced as the N source, Cp2Mg as the Mg source, TEGa as the Ga source, TMIn as the In source, and TMAl as the Al source in the MOCVD reaction chamber, with N2 as the carrier gas.

[0058] S700: A P-type GaN layer is grown on an electron blocking layer;

[0059] Specifically, a P-type GaN layer was grown in MOCVD at a temperature of 980℃-1050℃ and a pressure of 100 torr-300 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source, and Cp2Mg was introduced as the P-type doping source; H2 and N2 were used as carrier gases, and TMGa was introduced as the Ga source.

[0060] The present invention will be further described below with reference to specific embodiments:

[0061] Example 1

[0062] This embodiment provides a light-emitting diode epitaxial wafer, referenced... Figure 1 , Figure 2 and Figure 4 It includes a substrate 1 and a buffer layer 2, an undoped GaN layer 3, an N-type GaN layer 4, an active layer 5, an electron blocking layer 6, and a P-type GaN layer 7 sequentially disposed on the substrate 1.

[0063] In this design, substrate 1 is a sapphire substrate; buffer layer 2 is an AlGaN layer with a thickness of 30 nm; undoped GaN layer 3 has a thickness of 1.5 μm; and the Si doping concentration in N-type GaN layer 4 is 7 × 10⁻⁶. 18 cm -3 Its thickness is 2μm. The active layer 5 consists of alternating stacked InGaN quantum well layers and GaN quantum barrier layers, with a stacking period of 10. The thickness of a single InGaN quantum well layer is 3nm, and the thickness of a single GaN quantum barrier layer is 10nm.

[0064] Among them, electron blocking layer 6 is an Al co-doped with Mn / Zn. x In y Ga 1-x-y N-layer 61. Mn / Zn co-doped Al x In y Ga 1-x-y The Mn doping concentration in N-layer 61 is 5 × 10⁻⁶. 20 cm -3 The Zn doping concentration is 5 × 10⁻⁶. 20 cm -3 The x-axis is 0.5, the y-axis is 0.1, and the thickness is 120nm.

[0065] In this layer, the doping element of the p-type GaN layer 7 is Mg, and the doping concentration is 5 × 10⁻⁶. 19 cm -3 The thickness is 15nm.

[0066] The method for fabricating the epitaxial wafer of the light-emitting diode in this embodiment includes the following steps:

[0067] (1) Provide a substrate;

[0068] (2) Grow a buffer layer on the substrate;

[0069] Specifically, the AlGaN layer was grown using MOCVD at a growth temperature of 600℃ and a growth pressure of 300 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source; H2 and N2 were used as carrier gases; TMAl was introduced as the Al source; and TMGa was introduced as the Ga source.

[0070] (3) Grow an undoped GaN layer on the buffer layer;

[0071] Specifically, undoped GaN layers were grown using MOCVD at a growth temperature of 1100℃ and a growth pressure of 200 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source, and H2 and N2 were used as carrier gases, while TMGa was introduced as the Ga source.

[0072] (4) An N-type GaN layer is grown on an undoped GaN layer;

[0073] Specifically, an N-type GaN layer was grown using MOCVD at a growth temperature of 1100℃ and a growth pressure of 300 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as an N source and SiH4 was introduced as an N-type doping source. H2 and N2 were used as carrier gases, and TMGa was introduced as a Ga source.

[0074] (5) An active layer is grown on the N-type GaN layer;

[0075] Specifically, InGaN quantum well layers and GaN quantum barrier layers are periodically grown in MOCVD to obtain active layers. The growth temperature of the InGaN quantum well layer is 780℃, and the growth pressure is 200 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source, N2 is introduced as the carrier gas, TEGa is introduced as the Ga source, and TMIn is introduced as the In source. The growth temperature of the GaN quantum barrier layer is 880℃, and the growth pressure is 200 torr. During growth, NH3 is introduced into the MOCVD reaction chamber as the N source, H2 and N2 are introduced as the carrier gas, and TEGa is introduced as the Ga source.

[0076] (6) Grow an electron blocking layer on the active layer;

[0077] Specifically, Mn / Zn co-doped Al is grown on the active layer. x In y Ga 1-x-y The N-layer acts as an electron-blocking layer. Specifically, Mn / Zn co-doped Al is grown in MOCVD. x In y Ga 1-x-y The N-layer was grown at a temperature of 950℃ and a pressure of 100 torr. During growth, NH3 was introduced as the N source, TMMn as the Mn source, DMZn as the Zn source, TEGa as the Ga source, TMI as the In source, and TMI as the Al source in the MOCVD reaction chamber, with N2 as the carrier gas.

[0078] (7) Grow a P-type GaN layer on the electron blocking layer;

[0079] Specifically, a P-type GaN layer was grown in MOCVD at a temperature of 1000℃ and a pressure of 200 torr. During growth, NH3 was introduced into the MOCVD reaction chamber as the N source, and Cp2Mg was introduced as the P-type doping source; H2 and N2 were used as carrier gases, and TMGa was introduced as the Ga source.

[0080] Example 2

[0081] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 1 in that the Mn doping concentration is 1×10⁻⁶. 19 cm -3 The Zn doping concentration is 1×10⁻⁶. 19 cm -3 Its thickness is 50nm.

[0082] Everything else is the same as in Example 1.

[0083] Example 3

[0084] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 2 in that, with reference to... Figure 3 Electron blocking layer 6 also includes Mg-doped Al a In b Ga 1-a-b N-layer 62, Mg-doped Al a In b Ga 1-a-b N-layer 62 is located in Mn / Zn co-doped Al. x In y Ga 1-x- y Above layer N61. Mg-doped Al a Inb Ga 1-a-b The Mg doping concentration in layer 62 is 5 × 10⁻⁶. 19 cm -3 a = 0.3, b = 0.06, and the thickness is 25 nm. Correspondingly, in the preparation method, Mg-doped Al is grown in MOCVD. a In b Ga 1-a-b The N-layer was grown at a temperature of 900℃ and a pressure of 100 torr. During growth, NH3 was introduced as the N source, Cp2Mg as the Mg source, TEGa as the Ga source, TMIn as the In source, and TMAl as the Al source into the MOCVD reaction chamber, with N2 as the carrier gas.

[0085] Everything else is the same as in Example 2.

[0086] Example 4

[0087] This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 3 in that Al x In y Ga 1-x-y In layer N, y is 0. Mg-doped Al a In b Ga 1-a-b In layer N (62), 0.1 ≤ a ≤ 0.5, 0 ≤ b ≤ 0.1. Mg doped with Al a In b Ga 1-a-b The lattice constant of N-layer 62 is intermediate between that of Mn / Zn co-doped Al. x In y Ga 1-x-y Between the N-layer 61 and the P-type GaN layer 7, the size gradually increases along the direction of epitaxial growth.

[0088] Everything else is the same as in Example 3.

[0089] Comparative Example 1

[0090] This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that the electron blocking layer 6 in the epitaxial wafer is an AlGaN layer, the Al content in the AlGaN layer is 0.5%, and its thickness is 120 nm. Correspondingly, in the preparation method, the growth temperature of the AlGaN layer is 950 °C, the growth pressure is 100 torr, and the rest are the same as in Example 1.

[0091] Comparative Example 2

[0092] This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that the electron blocking layer 6 is not doped with Mn or Zn, while the rest is the same as Example 1.

[0093] Comparative Example 3

[0094] This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that the electron blocking layer 6 is not doped with Mn, while the rest is the same as Example 1.

[0095] The LED epitaxial wafers obtained in Examples 1-4 and Comparative Examples 1-3 were fabricated into 15mil*15mil chips using the same process conditions. 300 chips were fabricated for each example and comparative example, and tested at a current of 120mA. Using Comparative Example 1 as a benchmark, the improvement rate of luminous efficacy in each example was calculated. The specific calculation results are shown in the table below:

[0096]

[0097]

[0098] As can be seen from the table, changing the traditional electron blocking layer (Comparative Example 1) to the electron blocking layer structure of this invention effectively improves the luminous efficacy. Furthermore, a comparison between Example 1 and Comparative Examples 2-3 shows that changing the electron blocking layer structure of this invention is unlikely to effectively improve brightness.

[0099] The above description is a preferred embodiment of the invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the invention, and these improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A light-emitting diode epitaxial wafer, comprising a substrate and a buffer layer, an undoped GaN layer, an N-type GaN layer, an active layer, an electron blocking layer, and a P-type GaN layer sequentially disposed on the substrate; characterized in that, The electron blocking layer comprises Mn / Zn co-doped Al x In y Ga 1-x-y N layers; The Mn / Zn co-doped Al x In y Ga 1-x-y The Mn doping concentration in the N layer is 1×10⁻⁶. 18 cm -3 -1×10 20 cm -3 The Zn doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 20 cm -3 , 0.2≤x≤0.8, 0≤y≤0.

2.

2. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The Mn / Zn co-doped Al x In y Ga 1-x-y The thickness of the N layer is 10nm-100nm.

3. The light-emitting diode epitaxial wafer as described in claim 1 or 2, characterized in that, The electron blocking layer also includes Mg-doped Al. a In b Ga 1-a-b N-layer, the Mg-doped Al a In b Ga 1-a-b The N-layer is disposed on the Mn / Zn co-doped Al. x In y Ga 1-x-y Above the Nth floor.

4. The light-emitting diode epitaxial wafer as described in claim 3, characterized in that, The Mg-doped Al a In b Ga 1-a-b The Mg doping concentration in the N layer is 1×10⁻⁶. 17 cm -3 -1×10 19 cm -3 0.1≤a≤0.5, 0≤b≤0.1, the Mg doped with Al a In b Ga 1-a-b The thickness of the N layer is 5nm-20nm.

5. The light-emitting diode epitaxial wafer as described in claim 4, characterized in that, The Mg-doped Al a In b Ga 1-a-b The lattice constant of the N-layer is intermediate between that of the Mn / Zn co-doped Al. x In y Ga 1-x-y The distance between the N-layer and the P-type GaN layer gradually increases along the direction of epitaxial growth.

6. A method for preparing a light-emitting diode epitaxial wafer, used to prepare a light-emitting diode epitaxial wafer as described in any one of claims 1-5, characterized in that, include: A substrate is provided on which a buffer layer, an undoped GaN layer, an N-type GaN layer, an active layer, an electron blocking layer, and a P-type GaN layer are sequentially grown; the electron blocking layer comprises Mn / Zn co-doped Al. x In y Ga 1-x-y N layers.

7. The method for fabricating a light-emitting diode epitaxial wafer as described in claim 6, characterized in that, The Mn / Zn co-doped Al x In y Ga 1-x-y The growth temperature of the N layer is 850℃-1050℃, and the growth pressure is 50 torr-200 torr.

8. The method for fabricating a light-emitting diode epitaxial wafer as described in claim 6, characterized in that, The electron blocking layer also includes Mg-doped Al. a In b Ga 1-a-b N-layer, the Mg-doped Al a In b Ga 1-a-b The N-layer is disposed on the Mn / Zn co-doped Al. x In y Ga 1-x-y Above the N layer, the Mg-doped Al a In b Ga 1-a-b The growth temperature of the N layer is 800℃-1000℃, and the growth pressure is 50 torr-150 torr.

9. A light-emitting diode, characterized in that, Includes the light-emitting diode epitaxial wafer as described in any one of claims 1-5.

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