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

Abstract

The application relates to the field of semiconductor photoelectric devices, and particularly discloses a light-emitting diode epitaxial wafer, a preparation method thereof and a light-emitting diode. x Ga 1‑x N well layer, a first Ga-polarity GaN layer, a Ga-polarity Al a Ga 1‑a N layer and a second Ga-polarity GaN layer; the second active layer comprises an In y Ga 1‑y N well layer and a third Ga-polarity GaN layer; the third active layer comprises an In z Ga 1‑z N well layer, a first N-polarity GaN layer, an N-polarity Al b Ga 1‑b N layer and a second N-polarity GaN layer; wherein y < x < z, and a <= b. By implementing the application, the light-emitting efficiency 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] GaN-based LEDs are widely used in lighting, displays, and other fields. With increasing demands for healthy lighting and display quality, the industry has proposed multi-band light-emitting LEDs, which utilize two or more InGaN-GaN multiple quantum well layers with different In compositions on the same LED to achieve multi-band light emission. However, with this structure, the variation in In composition can easily lead to intensified polarization effects in the multiple quantum well layers, reducing electron-hole recombination efficiency and consequently lowering luminous efficiency. Furthermore, the different band bending degrees in multiple quantum well layers with different In compositions also result in significant differences in the mobility of electrons and holes across different energy bands, further reducing recombination efficiency. 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 its preparation method, which can improve the luminous efficiency.

[0004] Another technical problem that the present invention needs to solve is to provide a light-emitting diode.

[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 opening layer, a first active layer, a second active layer, a third active layer, and a P-type GaN layer sequentially stacked on the substrate. The opening layer comprises alternating layers of AlN and C, Mg co-doped AlGaN; The first active layer includes alternating layers of In x Ga 1-x An N-well layer and a first quantum barrier layer; the first quantum barrier layer comprises N-well layers sequentially stacked on the In... x Ga 1-x The first Ga polar GaN layer on the N-well layer, Ga polar Al a Ga 1-a N-layer and second Ga-polar GaN layer; The second active layer includes alternating layers of In y Ga 1-y The N-well layer and the second quantum barrier layer; the second quantum barrier layer is a third Ga polar GaN layer; The third active layer comprises alternating layers of In z Ga 1-z An N-well layer and a third quantum barrier layer; the third quantum barrier layer comprises layers sequentially stacked on top of the In... zGa 1-z The first N-polar GaN layer on the N-well layer, and the N-polar Al b Ga 1-b N-layer and second N-polar GaN layer; Where y < x < z, a ≤ b.

[0006] As an improvement to the above technical solution, along the growth direction of the light-emitting diode epitaxial wafer, the C doping concentration of the C and Mg co-doped AlGaN layer in the opening layers of different periods decreases, the Mg doping concentration increases, and the proportion of Al component increases.

[0007] As an improvement to the above technical solution, along the growth direction of the light-emitting diode epitaxial wafer, the Ga polar Al in the first active layer of different periods... a Ga 1-a The proportion of Al components in the N layer increases progressively.

[0008] As an improvement to the above technical solution, along the growth direction of the light-emitting diode epitaxial wafer, the N-polarity Al in the third active layer of different periods... b Ga 1-b The proportion of Al component in the N layer decreases.

[0009] As an improvement to the above technical solution, the number of periods of the opening layer is 3 to 8; The thickness of the AlN layer is 3nm~5nm; The thickness of the C and Mg co-doped AlGaN layer is 3 nm to 5 nm, and the C doping concentration is 1 × 10⁻⁶. 16 cm -3 ~1×10 17 cm -3 The Mg doping concentration is 1×10 16 cm -3 ~1×10 17 cm -3 Its Al component accounts for 0.05~0.2%.

[0010] As an improvement to the above technical solution, the number of cycles in the first active layer is 3 to 12; The In x Ga 1-x The thickness of the N-well layer is 2nm~3.5nm, and the value of x ranges from 0.18 to 0.3; The thickness of the first Ga polar GaN layer is 2nm~5nm; The Ga polar Al a Ga 1-a The thickness of layer N is 1nm to 4nm, and the value of a ranges from 0.05 to 0.1. The thickness of the second Ga polar GaN layer is 2nm~5nm; The number of periods in the second active layer is 3 to 12; The In y Ga 1-y The thickness of the N-well layer is 2nm~3.5nm, and the value of y ranges from 0.1 to 0.2. The thickness of the third Ga polar GaN layer is 8nm~15nm; The number of cycles in the third active layer is 3 to 12; The In z Ga 1-z The thickness of the N-well layer is 2nm~5nm, and the value of z ranges from 0.25 to 0.4. The thickness of the first N-polar GaN layer is 2nm~5nm; The N polarity Al b Ga 1-b The thickness of the N layer is 1nm to 4nm, and the value of b ranges from 0.08 to 0.15. The thickness of the second N-polar GaN layer is 2nm~5nm.

[0011] Accordingly, the present invention also discloses a method for preparing a light-emitting diode epitaxial wafer, used to prepare the above-mentioned light-emitting diode epitaxial wafer, characterized in that it includes: Provide substrate; A buffer layer, an undoped GaN layer, an N-type GaN layer, an opening layer, a first active layer, a second active layer, a third active layer, and a P-type GaN layer are sequentially grown on the substrate. The opening layer comprises alternating layers of AlN and C, Mg co-doped AlGaN; The first active layer includes alternating layers of In x Ga 1-x An N-well layer and a first quantum barrier layer; the first quantum barrier layer comprises N-well layers sequentially stacked on the In... x Ga 1-x The first Ga polar GaN layer on the N-well layer, Ga polar Al a Ga 1-a N-layer and second Ga-polar GaN layer; The second active layer includes alternating layers of In y Ga 1-y The second quantum barrier layer is an N-well layer and a second quantum barrier layer; the second quantum barrier layer is a third Ga polar GaN layer; after the growth of the last third Ga polar GaN layer of the second active layer is completed, it is annealed at 1000℃~1100℃ for 40min~100min in a mixed gas atmosphere of NH3, H2 and N2. The third active layer comprises alternating layers of In z Ga 1-z An N-well layer and a third quantum barrier layer; the third quantum barrier layer comprises layers sequentially stacked on top of the In... z Ga 1-z The first N-polar GaN layer on the N-well layer, and the N-polar Al b Ga 1-b N-layer and second N-polar GaN layer; Where y < x < z, a ≤ b.

[0012] As an improvement to the above technical solution, the growth temperature of the AlN layer is 900℃~1100℃, and the growth pressure is 100 torr~300 torr; The growth temperature of the C and Mg co-doped AlGaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr.

[0013] As an improvement to the above technical solution, the In x Ga 1-x The growth temperature of the N-well layer is 730℃~800℃, and the growth pressure is 100 torr~300 torr. The growth temperature of the first Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the Ga polar Al a Ga 1-a The growth temperature of the N layer is 870℃~1000℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the second Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the growth atmosphere of the first quantum barrier layer is a mixture of H2 and NH3, and the volume ratio of H2 to NH3 is 1:8~1:12. The In y Ga 1-y The growth temperature of the N-well layer is 740℃~810℃, and the growth pressure is 100 torr~300 torr; The growth temperature of the third Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the growth atmosphere of the second quantum barrier layer is a mixture of H2 and NH3, and the volume ratio of H2 to NH3 is 1:8~1:12. The In z Ga 1-z The growth temperature of the N-well layer is 750℃~800℃, and the growth pressure is 100 torr~300 torr. The growth temperature of the first N-polar GaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr; The N polarity Al b Ga 1-b The growth temperature of the N layer is 820℃~900℃, and the growth pressure is 100 torr~300 torr; The growth temperature of the second N-polar GaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr; The growth atmosphere of the third quantum barrier layer is a mixture of N2 and NH3, with a volume ratio of N2 to NH3 of 1:1 to 1:5.

[0014] Accordingly, the present invention also discloses a light-emitting diode, which includes the above-described light-emitting diode epitaxial wafer.

[0015] Implementing this invention has the following beneficial effects: In one embodiment of the present invention, the epitaxial wafer of a light-emitting diode includes a substrate, on which a buffer layer, an undoped GaN layer, an N-type GaN layer, an opening layer, a first active layer, a second active layer, a third active layer, and a P-type GaN layer are sequentially stacked; wherein, the opening layer includes alternating layers of AlN layers and C, Mg co-doped AlGaN layers; the first active layer includes alternating layers of In... x Ga 1-x An N-well layer and a first quantum barrier layer; the first quantum barrier layer comprises N-well layers sequentially stacked on the In... x Ga 1-x The first Ga polar GaN layer on the N-well layer, Ga polar Al a Ga 1-a The second active layer comprises an N-layer and a second Ga-polar GaN layer; the second active layer includes alternating layers of In. y Ga 1-y The N-well layer and the second quantum barrier layer; the second quantum barrier layer is a third Ga polar GaN layer; the third active layer comprises alternating layers of In. z Ga 1-z The N-well layer and the third quantum barrier layer; the third quantum barrier layer consists of N-well layers stacked sequentially on In... z Ga 1-z The first N-polar GaN layer on the N-well layer, and the N-polar Al b Ga 1-bN-layer and second N-polar GaN layer; y < x < z, a ≤ b. Based on the above-mentioned LED epitaxial wafer, firstly, an AlN layer and a C, Mg co-doped AlGaN layer are introduced as opening layers. This not only reduces dislocation extension in the underlying layer and improves the crystal quality of the subsequent growth of the first, second, and third active layers, but also effectively controls the formation density and opening size of V-shaped pits, strengthening the dislocation shielding effect of the V-shaped pits and improving luminous efficiency and uniformity. Secondly, the high-barrier opening layer reduces the electron migration speed. In addition, Mg doping can also generate holes, consuming excessive electrons. The combination of these two improves the electron-hole matching degree in the first, second, and third active layers, thereby improving luminous efficiency. Thirdly, by sequentially forming In with a high In content on the opening layer... x Ga 1-x The first active layer consists of an N-well layer and a Ga-polar first quantum barrier layer, along with an In layer with a relatively low In content. y Ga 1-y The second active layer, composed of an N-well layer and a Ga-polarized second quantum barrier layer, allows the V-shaped pits to effectively extend to the first and second active layers, fully leveraging their dislocation suppression capabilities and improving the luminous efficiency of the first and second active layers. Furthermore, by employing an N-polarized quantum barrier layer in the third active layer, the luminous efficiency of In with a high In content can be significantly improved. z Ga 1-z The incorporation efficiency of the In component in the N-well layer is improved, preventing segregation and enhancing luminescence efficiency. Simultaneously, the growth of this third active layer effectively promotes the merging and filling of V-shaped pits, increasing the luminescent area and reducing current leakage. Furthermore, the polarization field in this third active layer is opposite to the applied bias field, weakening the polarization electric field, flattening the energy band, and improving electron-hole recombination efficiency, thus enhancing luminescence efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a light-emitting diode epitaxial wafer in one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the opening layer in one embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the first active layer in one embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the second active layer in one embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the third active layer in one embodiment of the present invention; Figure 6 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.

[0017] In this diagram, 100 is the substrate, 200 is the buffer layer, 300 is the undoped GaN layer, 400 is the N-type GaN layer, 500 is the opening layer, 510 is the AlN layer, 520 is the C / Mg co-doped AlGaN layer, 600 is the first active layer, and 610 is the In layer. x Ga 1-x N-well layer, 620 is the first quantum barrier layer, 621 is the first Ga polar GaN layer, 622 is the Ga polar Al layer. a Ga 1-a N-layer, 623 is the second Ga polar GaN layer, 700 is the second active layer, 710 is the In layer. y Ga 1-y The N-well layer, 720 is the second quantum barrier layer, 800 is the third active layer, and 810 is the In layer. z Ga 1-z N-well layer, 820 is the third quantum barrier layer, 821 is the first N-polar GaN layer, 822 is the N-polar Al layer. b Ga 1-b The N-layer is 823, which is the second N-polar GaN layer, and the P-type GaN layer is 900. Detailed Implementation

[0018] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] In this invention, terms such as "first aspect" and "second aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional range of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0022] Please see Figures 1-5 As a first aspect of the present invention, an epitaxial wafer for a light-emitting diode is disclosed, comprising a substrate 100, and a buffer layer 200, an undoped GaN layer 300, an N-type GaN layer 400, an opening layer 500, a first active layer 600, a second active layer 700, a third active layer 800, and a P-type GaN layer 900 sequentially stacked on the substrate 100. The opening layer 500 comprises alternating layers of AlN layers 510 and C, Mg co-doped AlGaN layers 520; the first active layer 600 comprises alternating layers of In… x Ga 1- x N-well layer 610 and first quantum barrier layer 620; the first quantum barrier layer 620 comprises N-well layers sequentially stacked on In... x Ga 1-x The first Ga-polar GaN layer 621 and Ga-polar Al layer on the N-well layer 610 a Ga 1-a N layer 622 and second Ga polar GaN layer 623; second active layer 700 includes alternating layers of In y Ga 1-y N-well layer 710 and second quantum barrier layer 720; the second quantum barrier layer 720 is a third Ga polar GaN layer; the third active layer 800 includes alternating layers of In z Ga 1-z N-well layer 810 and third quantum barrier layer 820; the third quantum barrier layer 820 comprises N-well layers 810 and 820 respectively stacked on In. z Ga 1-z The first N-polar GaN layer 821 and N-polar Al on the N-well layer 810 b Ga 1-bN-layer 822 and second N-polar GaN layer 823; y < x < z, a ≤ b. Based on the above-mentioned LED epitaxial wafer, firstly, an AlN layer 510 and a C, Mg co-doped AlGaN layer 520 are introduced as an opening layer 500. This not only reduces dislocation extension in the underlying layer and improves the crystal quality of the subsequent growth of the first active layer 600, the second active layer 700, and the third active layer 800, but also effectively controls the formation density and opening size of the V-shaped pits, strengthening the dislocation shielding effect of the V-shaped pits and improving luminous efficiency and luminous uniformity. Secondly, the high-barrier opening layer 500 can reduce the electron migration speed. In addition, Mg doping can also generate holes, consuming excessive electrons. The combination of these two improves the electron-hole matching degree in the first active layer 600, the second active layer 700, and the third active layer 800, thereby improving luminous efficiency. Thirdly, by sequentially forming In with a high proportion of In composition on the opening layer 500... x Ga 1-x The first active layer 600 consists of an N-well layer 610 and a Ga-polar first quantum barrier layer 620, and an In layer with a low In content. y Ga 1-y The second active layer 700, composed of an N-well layer 710 and a Ga-polarized second quantum barrier layer 720, allows the V-shaped pits to effectively extend to the first active layer 600 and the second active layer 700, fully leveraging their dislocation suppression function and improving the luminous efficiency of the first active layer 600 and the second active layer 700. Fourthly, employing an N-polarized quantum barrier layer in the third active layer 800 can significantly improve the luminous efficiency of In with a high In content. z Ga 1-z The incorporation efficiency of the In component in the N-well layer 810 is improved, preventing segregation and enhancing luminescence efficiency. Simultaneously, the growth of this third active layer 800 effectively promotes the merging and filling of V-shaped pits, increasing the luminescent area and reducing current leakage. Furthermore, the polarization field in this third active layer 800 is opposite to the applied bias field, weakening the polarization electric field, flattening the energy band, and improving electron-hole recombination efficiency, thus enhancing luminescence efficiency.

[0023] Specifically, the number of cycles of the opening layer 500 is 2 to 12, exemplarily 3, 5, 7, 9 or 11, but not limited thereto. Preferably, in some embodiments, the number of cycles of the opening layer 500 is 2 to 10. More preferably, it is 3 to 8.

[0024] Specifically, the thickness of the AlN layer 510 is 2nm to 5nm, exemplarily 2.5nm, 3nm, 3.5nm, 4nm, or 4.5nm, but not limited thereto. Preferably, in some embodiments, the thickness of the AlN layer 510 is 3nm to 5nm. More preferably, it is 3.5nm to 5nm.

[0025] Specifically, the thickness of the C and Mg co-doped AlGaN layer 520 is 2nm to 5nm, exemplarily 2.5nm, 3nm, 3.5nm, 4nm, or 4.5nm, but not limited thereto. Preferably, the thickness of the C and Mg co-doped AlGaN layer 520 is 3nm to 5nm.

[0026] Specifically, the C doping concentration in the C, Mg co-doped AlGaN layer 520 is 1×10⁻⁶. 16 cm -3 ~5×10 17 cm -3 The C doping concentration is related to the aperture density and aperture size of the V-shaped pits. If the C doping concentration is too low, the aperture density of the V-shaped pits is small, and the dislocation shielding effect is weakened. If the C doping concentration is too high, it will introduce too many non-radiative recombination centers, leading to a decrease in luminous efficiency. For example, the C doping concentration in the C and Mg co-doped AlGaN layer 520 is 3 × 10⁻⁶. 16 cm -3 5×10 16 cm -3 7×10 16 cm -3 9×10 16 cm -3 1×10 17 cm -3 Or 3×10 17 cm -3 However, this is not the only possibility. Preferably, in some embodiments, the C doping concentration in the C, Mg co-doped AlGaN layer 520 is 1 × 10⁻⁶. 16 cm -3 ~1×10 17 cm -3 More preferably, 3×10 16 cm -3 ~1×10 17 cm -3 .

[0027] Specifically, compared to the technical solution without introducing the opening layer 500, the opening density of the V-shaped pit increases from 0.8 × 10⁻⁶ to 500 mm after introducing the opening layer 500. 8 cm -2 ~1.3×10 8 cm -2 Increased to 1.5 × 10 8 cm -2 ~2.0×10 8 cm -2 The opening diameter of the V-shaped pit increased from 75nm~100nm to 250nm~300nm.

[0028] Specifically, the Mg doping concentration in the C, Mg co-doped AlGaN layer 520 is 1×10⁻⁶. 16 cm -3 ~5×10 17 cm -3 For example, 3×10 16 cm -3 5×10 16 cm -3 7×10 16 cm -3 9×10 16 cm -3 1×10 17 cm -3 Or 3×10 17 cm -3 However, this is not the only possibility. Preferably, in some embodiments, the Mg doping concentration in the C, Mg co-doped AlGaN layer 520 is 1 × 10⁻⁶. 16 cm -3 ~1×10 17 cm -3 More preferably, it is 1×10. 16 cm -3 ~8×10 16 cm -3 .

[0029] Specifically, the proportion of Al component in the C and Mg co-doped AlGaN layer 520 is 0.05~0.25, exemplarily 0.08, 0.1, 0.12, 0.15, 0.17, 0.19, 0.21 or 0.23, but not limited thereto. Preferably, in some embodiments, the proportion of Al component in the C and Mg co-doped AlGaN layer 520 is 0.05~0.2, more preferably 0.08~0.15.

[0030] Specifically, the number of cycles in the first active layer 600 is 2 to 12, exemplarily 3, 5, 7, 9 or 11, but not limited thereto. Preferably, in some embodiments, the number of cycles in the first active layer 600 is 3 to 12.

[0031] Specifically, in x Ga 1-x The thickness of the N-well layer 610 is 2nm to 4nm, exemplarily 2.5nm, 3nm, or 3.5nm, but not limited thereto. Preferably, In x Ga 1-x The thickness of the N-well layer 610 is 2nm to 3.5nm, more preferably 2.5nm to 3nm.

[0032] Specifically, in x Ga 1-xThe proportion of In component in the N-well layer 610 (i.e., the value range of x) is 0.15 to 0.3, exemplarily 0.18, 0.20, 0.22, 0.25, or 0.28, but not limited thereto. Preferably, in some embodiments, the value range of x is 0.18 to 0.3, more preferably 0.18 to 0.25.

[0033] Specifically, the first quantum barrier layer 620 in the first active layer 600 is Ga polar, and its polarity determines that the V-shaped pit will continue to extend due to dislocation induction, thereby playing a role in dislocation annihilation. Furthermore, the Ga polar Al introduced into the first quantum barrier layer 620... a Ga 1-a The N-layer 622 can also weaken the polarization electric field, improve carrier recombination efficiency, and thus improve the overall luminescence efficiency.

[0034] Specifically, the thickness of the first Ga polar GaN layer 621 is 2nm to 6nm; exemplaryly, it is 2.5nm, 3nm, 3.5nm, 4nm, 4.5nm, 5nm, or 5.5nm, but is not limited thereto. Preferably, in some embodiments, the thickness of the first Ga polar GaN layer 621 is 2nm to 5nm, more preferably 3nm to 4nm.

[0035] Specifically, Ga polar Al a Ga 1-a The thickness of the N-layer 622 is 1 nm to 5 nm, exemplarily 1.5 nm, 2 nm, 2.5 nm, 3 nm, or 3.5 nm, but not limited thereto. Preferably, in some embodiments, Ga polar Al a Ga 1-a The thickness of the N-layer 622 is 1nm to 4nm, more preferably 2nm to 4nm.

[0036] Specifically, Ga polar Al a Ga 1-a The proportion of Al component in layer N 622 (i.e., the value range of α) is 0.05~0.15. If it is >0.15, new dislocations will be introduced; if it is <0.05, it will be difficult to effectively weaken the compressive strain. For example, the value of α is 0.08, 0.1, 0.12 or 0.14, but is not limited to these. Preferably, in some embodiments, the value range of α is 0.05~0.1, more preferably 0.08~0.1.

[0037] Specifically, the thickness of the second Ga polar GaN layer 623 is 2nm to 6nm; exemplary thicknesses are 2.5nm, 3nm, 3.5nm, 4nm, 4.5nm, 5nm, or 5.5nm, but are not limited thereto. Preferably, in some embodiments, the thickness of the second Ga polar GaN layer 623 is 2nm to 5nm, more preferably 3nm to 4nm.

[0038] Specifically, the number of cycles in the second active layer 700 is 2 to 12, exemplarily 3, 5, 7, 9 or 11, but not limited thereto. Preferably, in some embodiments, the number of cycles in the second active layer 700 is 3 to 12.

[0039] Specifically, in y Ga 1-y The thickness of the N-well layer 710 is 2nm to 4nm, exemplarily 2.5nm, 3nm, or 3.5nm, but not limited thereto. Preferably, In y Ga 1-y The thickness of the N-well layer 710 is 2nm to 3.5nm, more preferably 2.5nm to 3.5nm.

[0040] Specifically, in y Ga 1-y The proportion of In component in the N-well layer 710 (i.e., the value range of y) is 0.1 to 0.25, exemplarily 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, or 0.24, but not limited thereto. Preferably, in some embodiments, the value range of y is 0.1 to 0.2, more preferably 0.12 to 0.18.

[0041] Specifically, the second quantum barrier layer 720 in the second active layer 700 is Ga polar, specifically a third Ga polar GaN layer, which has high flatness and can promote the continued extension of V-shaped pits and promote dislocation annihilation.

[0042] Specifically, the thickness of the third Ga polar GaN layer is 8nm to 15nm, exemplarily 9nm, 11nm, 13nm or 14nm, but not limited thereto. Preferably, it is 10nm to 15nm.

[0043] Specifically, the number of cycles in the third active layer 800 is 2 to 12, exemplarily 3, 5, 7, 9 or 11, but not limited thereto. Preferably, in some embodiments, the number of cycles in the third active layer 800 is 3 to 12.

[0044] Specifically, in z Ga 1-zThe thickness of the N-well layer 810 is 2nm to 5nm, exemplarily 2.5nm, 3nm, 3.5nm, 4nm, or 4.5nm, but not limited thereto. Preferably, In z Ga 1-z The thickness of the N-well layer 810 is 3nm~5nm, more preferably 3.5nm~4.5nm.

[0045] Specifically, in z Ga 1-z The proportion of In component in the N-well layer 810 (i.e., the value range of z) is 0.25~0.45, exemplarily 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42 or 0.44, but not limited thereto. Preferably, in some embodiments, the value range of z is 0.25~0.4, more preferably 0.28~0.35.

[0046] Specifically, the third quantum barrier layer 820 in the third active layer 800 is N-polar, which can promote the production of In with a high In content. z Ga 1-z The uniform distribution of In in the N-well layer 810 reduces In segregation and improves luminescence efficiency. Moreover, the N-polar third quantum barrier layer 820 also introduces a polarization field opposite to the applied bias field, flattening the energy band and improving luminescence efficiency.

[0047] Specifically, the thickness of the first N-polar GaN layer 821 is 2nm to 6nm; exemplaryly, it is 2.5nm, 3nm, 3.5nm, 4nm, 4.5nm, 5nm, or 5.5nm, but is not limited thereto. Preferably, in some embodiments, the thickness of the first N-polar GaN layer 821 is 2nm to 5nm, more preferably 3nm to 4nm.

[0048] Specifically, N-polarity Al b Ga 1-b The thickness of the N-layer 822 is 1nm to 5nm, exemplarily 1.5nm, 2nm, 2.5nm, 3nm, 3.5nm, 4nm, or 4.5nm, but not limited thereto. Preferably, in some embodiments, the N-polarity Al... b Ga 1-b The thickness of the N-layer 822 is 1nm to 4nm, more preferably 2nm to 4nm.

[0049] Specifically, N-polarity Al b Ga 1-bThe proportion of Al component in layer N 822 (i.e., the value range of b) is 0.08~0.2, exemplarily 0.1, 0.12, 0.14, 0.16 or 0.18, but not limited thereto. Preferably, in some embodiments, the value range of b is 0.08~0.15, more preferably 0.1~0.15.

[0050] Specifically, the thickness of the second N-polar GaN layer 823 is 2nm to 6nm; exemplary thicknesses are 2.5nm, 3nm, 3.5nm, 4nm, 4.5nm, 5nm, or 5.5nm, but are not limited thereto. Preferably, in some embodiments, the thickness of the second N-polar GaN layer 823 is 2nm to 5nm, more preferably 3nm to 4nm.

[0051] Specifically, the substrate 100 is any one of a sapphire substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and a gallium oxide substrate, but is not limited thereto. Preferably, it is a sapphire substrate.

[0052] Specifically, the buffer layer 200 is an AlN layer, a GaN layer, or an AlGaN layer, but is not limited to these. The thickness of the buffer layer 200 is 30 nm to 80 nm.

[0053] Specifically, the thickness of the undoped GaN layer 300 is 1 μm to 3 μm.

[0054] Specifically, the N-type GaN layer 400 is doped with Si, but is not limited to this. The Si doping concentration in the N-type GaN layer 400 is 1 × 10⁻⁶. 18 cm -3 ~5×10 19 cm -3 Its thickness is 1μm~5μm.

[0055] Specifically, the doping element of the p-type GaN layer 900 is Mg, but it is not limited to this. The doping concentration of Mg in the p-type GaN layer 900 is 1×10⁻⁶. 19 cm -3 ~5×10 20 cm -3 Its thickness is 80nm~200nm.

[0056] Preferably, in some embodiments, along the growth direction of the LED epitaxial wafer, the C doping concentration of the C and Mg co-doped AlGaN layers 520 in different periods of the opening layers 500 decreases, the Mg doping concentration increases, and the proportion of Al component increases. Based on this, the migration rate and injection amount of electron carriers into the first active layer 600, the second active layer 700, and the third active layer 800 can be better adjusted, controlling the distribution density and opening size of the V-shaped pits and improving luminous efficiency. The increasing and decreasing changes can be linear, gradient, or polynomial changes, but are not limited to these. In the C and Mg co-doped AlGaN layers 520 of the same period, the C doping concentration can decrease uniformly or correspondingly along its thickness direction; the Mg doping concentration and the proportion of Al component can increase uniformly or correspondingly along its thickness direction, but are not limited to these. Preferably, along the growth direction of the LED epitaxial wafer, the C doping concentration of the C and Mg co-doped AlGaN layer 520 in the opening layer 500 of different periods varies from 8 × 10⁻⁶ to 10⁻⁶. 16 cm -3 ~1×10 17 cm -3 linearly decreasing to 1×10 16 cm -3 ~4×10 16 cm -3 The Mg doping concentration was 1×10 16 cm -3 ~4×10 16 cm -3 linearly increasing to 8×10 16 cm -3 ~1×10 17 cm -3 The proportion of Al component increases linearly from 0.05~0.1 to 0.14~0.2%. Moreover, in a single period of C and Mg co-doped AlGaN layer 520, the C doping concentration, Mg doping concentration, and proportion of Al component do not change with thickness.

[0057] Preferably, in some embodiments, along the growth direction of the light-emitting diode epitaxial wafer, Ga polar Al in the first active layer 600 of different periods a Ga 1-a The proportion of Al component in the N-layer 622 increases progressively. Based on this, the polarization electric field can be further weakened to improve luminous efficiency. This increasing variation can be linear, gradient-like, or polynomial, but is not limited to these. In the same period, Ga polar Al... a Ga 1-a In the N-layer 622, the proportion of Al component can vary uniformly or progressively along its thickness direction, but is not limited thereto. Preferably, along the growth direction of the LED epitaxial wafer, the Ga-polar Al component in the first active layer 600 of different periods...a Ga 1-a The proportion of Al component in the N-layer 622 increases linearly from 0.05~0.07 to 0.08~0.1, and the polar Al component in a single cycle... a Ga 1-a In the N-layer 622, the proportion of Al component does not change with thickness.

[0058] Preferably, in some embodiments, along the growth direction of the light-emitting diode epitaxial wafer, the N-polarity Al in the third active layer 800 of different periods... b Ga 1-b The proportion of Al component in the N-layer 822 decreases progressively. This effectively prevents electron carrier leakage, improves hole injection efficiency, and enhances luminescence efficiency. The decreasing proportion can be linear, gradient-like, or polynomial, but is not limited to these. In the same period, N-polarity Al... b Ga 1-b In the N-layer 822, the proportion of Al component can vary uniformly or decrease accordingly along its thickness direction, but is not limited to this. Preferably, along the growth direction of the light-emitting diode epitaxial wafer, the N-polarity Al in the third active layer 800 of different periods... b Ga 1-b The proportion of Al component in the N-layer 822 decreases linearly from 0.14~0.15 to 0.08~0.11, and the N-polarity Al in a single cycle... b Ga 1-b In the N-layer 822, the proportion of Al component does not change with its thickness.

[0059] Accordingly, please refer to Figure 6 As a second aspect of the present invention, the present invention also provides a method for preparing a light-emitting diode epitaxial wafer, which includes the following steps: S1: Provides a substrate; S2: A buffer layer, an undoped GaN layer, an N-type GaN layer, an opening layer, a first active layer, a second active layer, a third active layer, and a P-type GaN layer are grown sequentially on the substrate. The opening layer comprises alternating layers of AlN and C, Mg co-doped AlGaN; the first active layer comprises alternating layers of In. x Ga 1-x An N-well layer and a first quantum barrier layer; the first quantum barrier layer comprises N-well layers sequentially stacked on the In... x Ga 1-x The first Ga polar GaN layer on the N-well layer, Ga polar Al a Ga 1-a The second active layer comprises an N-layer and a second Ga-polar GaN layer; the second active layer includes alternating layers of In. y Ga 1-yThe N-well layer and the second quantum barrier layer; the second quantum barrier layer is a third Ga polar GaN layer; the third active layer comprises alternating layers of In. z Ga 1-z The N-well layer and the third quantum barrier layer; the third quantum barrier layer consists of N-well layers stacked sequentially on In... z Ga 1-z The first N-polar GaN layer on the N-well layer, and the N-polar Al b Ga 1-b N-layer and second N-polar GaN layer; y < x < z, a ≤ b. Based on the above method for fabricating LED epitaxial wafers, firstly, the open layer reduces dislocation extension in the bottom layer, improves the crystal quality of subsequent layers, and can effectively control the formation density and opening size of V-shaped pits, strengthening the dislocation shielding effect of V-shaped pits and improving luminous efficiency and uniformity. Secondly, the high-barrier open layer can reduce the electron migration speed, and Mg doping can also generate holes, consuming excessive electrons. The combination of the two improves the electron-hole matching degree in the first, second, and third active layers, thus improving luminous efficiency. Thirdly, the first and second active layers can effectively expand and extend V-shaped pits, giving full play to their dislocation suppression effect and improving the luminous efficiency of the first and second active layers. Fourthly, the use of an N-polar quantum barrier layer in the third active layer can significantly improve the luminous efficiency of In with a high In content. z Ga 1-z The incorporation efficiency of the In component in the N-well layer is improved, preventing segregation and enhancing luminescence efficiency. Simultaneously, the growth of this third active layer effectively promotes the merging and filling of V-shaped pits, increasing the luminescent area and reducing current leakage. Furthermore, the polarization field in this third active layer is opposite to the applied bias field, weakening the polarization electric field, flattening the energy band, and improving electron-hole recombination efficiency, thus enhancing luminescence efficiency.

[0060] Specifically, in some implementations, step S2 includes: S21: Grow a buffer layer on the substrate; The buffer layer can be grown using PVD, MOCVD, MBE, or VPE, but is not limited to these methods.

[0061] Preferably, in one embodiment of the present invention, an AlN layer is grown by PVD as a buffer layer.

[0062] S22: Growing an undoped GaN layer on the buffer layer; Specifically, in some embodiments, undoped GaN layers are grown by MOCVD at a growth temperature of 1000℃~1200℃ and a growth pressure of 100 torr~500 torr.

[0063] S23: Growing an N-type GaN layer on an undoped GaN layer; Specifically, in some embodiments, an N-type GaN layer is grown using MOCVD at a growth temperature of 1000℃~1200℃ and a growth pressure of 100 torr~500 torr.

[0064] S24: Growing an open layer on an N-type GaN layer; Specifically, in some implementations, AlN layers and C / Mg co-doped AlGaN layers are periodically grown on an N-type GaN layer using MOCVD until an open layer is obtained. The growth temperature of the AlN layer is 900℃~1100℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the C / Mg co-doped AlGaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr.

[0065] Preferably, in some embodiments, when growing C and Mg co-doped AlGaN layers with different cycles, the C doping concentration, Al composition, and Mg doping concentration in the C and Mg co-doped AlGaN layer can be controlled by adjusting the flow rates of the C source (TMGa), Al source (TMAl), and Mg source (Cp2Mg).

[0066] S25: The first active layer is grown on the open layer; Specifically, in some implementations, In is grown periodically via MOCVD. x Ga 1-x The process continues with the N-well layer and the first quantum barrier layer until the first active layer is obtained. Wherein... x Ga 1-x The growth temperature of the N-well layer is 730℃~800℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the first Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; Ga polar Al a Ga 1-a The growth temperature of the N layer is 870℃~1000℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the second Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the growth atmosphere of the first quantum barrier layer is a mixture of H2 and NH3, with a volume ratio of H2 to NH3 of 1:8~1:12.

[0067] Preferably, in some embodiments, Ga polar Al is grown at different cycles. a Ga 1-a With N layers, Ga polarity Al can be achieved by controlling the flow rate of the Al source (TMAl). a Ga 1-a The proportion of Al components in the N layer is regulated.

[0068] S26: Grow a second active layer on the first active layer; Specifically, in some implementations, In is grown periodically via MOCVD. y Ga 1-y The process continues with an N-well layer and a second quantum barrier layer until a second active layer is obtained. Wherein... y Ga 1-y The growth temperature of the N-well layer is 740℃~810℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the third Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the growth atmosphere of the second quantum barrier layer is a mixture of H2 and NH3, with a volume ratio of H2 to NH3 of 1:8~1:12.

[0069] Specifically, after the growth of the last third Ga polar GaN layer in the second active layer is completed, it is annealed at 1000℃~1100℃ for 40min~100min in a mixed gas atmosphere of NH3, H2, and N2; wherein the volume ratio of NH3, H2, and N2 is (1.5~4):(1~3):(1.5~4). During the annealing process, H2 selectively etches the Ga surface domain regions on the surface of the third Ga polar GaN layer, providing a good N polar template for subsequent N-face growth. NH3 can inhibit the overall decomposition of the third Ga polar GaN layer, and N2 serves as a dilution carrier gas.

[0070] S27: Grow a third active layer on the second active layer; Specifically, in some implementations, In is grown periodically via MOCVD. z Ga 1-z The process continues with the N-well layer and the third quantum barrier layer until the third active layer is obtained. In... z Ga 1-z The growth temperature of the N-well layer is 750℃~800℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the first N-polar GaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr; the N-polar Al... b Ga 1-b The growth temperature of the N-layer is 820℃~900℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the second N-polar GaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr; the growth atmosphere of the third quantum barrier layer is a mixture of N2 and NH3, with a volume ratio of N2 to NH3 of 1:1~1:5.

[0071] Preferably, in some embodiments, N-polarity Al is grown for different periods. b Ga1-b In the N-layer configuration, N-polarity Al can be achieved by controlling the flow rate of the Al source (TMAl). b Ga 1-b The proportion of Al components in the N layer is regulated.

[0072] S28: Grow a P-type GaN layer on the third active layer; Specifically, in some implementations, a P-type GaN layer is grown by MOCVD at a growth temperature of 950°C to 1000°C and a growth pressure of 100 torr to 300 torr.

[0073] Accordingly, as a third aspect of the present invention, the present invention also provides a light-emitting diode comprising the above-described light-emitting diode epitaxial wafer.

[0074] The present invention will be further described below with reference to specific embodiments: Example 1 This embodiment provides a light-emitting diode epitaxial wafer, which includes a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, an opening layer, a first active layer, a second active layer, a third active layer and a P-type GaN layer sequentially stacked on the substrate.

[0075] The substrate is sapphire; the buffer layer is an AlN layer with a thickness of 30 nm; the undoped GaN layer has a thickness of 1.5 μm; and the Si doping concentration in the N-type GaN layer is 6.5 × 10⁻⁶. 18 cm -3 .

[0076] The open layer comprises alternating layers of AlN and C / Mg co-doped AlGaN, with a period of 6. The AlN layer is 4 nm thick, and the C / Mg co-doped AlGaN layer is 4.5 nm thick, with a C doping concentration of 5.5 × 10⁻⁶. 16 cm -3 The Mg doping concentration is 7×10 16 cm -3 The proportion of Al component is 0.12%. Furthermore, the C doping concentration, Mg doping concentration, and Al component proportion are all the same in C and Mg co-doped AlGaN layers of different periods.

[0077] The first active layer consists of alternating layers of In x Ga 1-x The N-well layer (x=0.22) and the first quantum barrier layer have a period number of 5. x Ga 1-x The thickness of the N-well layer is 3 nm. The first quantum barrier layer consists of a first Ga polar GaN layer and a Ga polar Al layer stacked sequentially. a Ga 1-aThe N-layer (a=0.08) and the second Ga-polar GaN layer; the thickness of the first Ga-polar GaN layer is 4nm, and the Ga-polar Al... a Ga 1-a The thickness of the N-layer is 3 nm, and the thickness of the second Ga-polar GaN layer is 4 nm. Ga-polar Al layers with different periods... a Ga 1-a In the N layer, the proportion of Al components is the same.

[0078] The second active layer consists of alternating layers of In y Ga 1-y The N-well layer (y=0.14) and the second quantum barrier layer have a period number of 5. y Ga 1-y The thickness of the N-well layer is 3 nm. The second quantum barrier layer is a third Ga polar GaN layer with a thickness of 10 nm.

[0079] The third active layer consists of alternating layers of In z Ga 1-z The N-well layer (z=0.33) and the third quantum barrier layer have a period number of 4. z Ga 1-z The thickness of the N-well layer is 3.5 nm. The third quantum barrier layer consists of a first N-polar GaN layer and an N-polar Al layer stacked sequentially. b Ga 1-b An N-layer (b=0.12) and a second N-polar GaN layer; wherein the thickness of the first N-polar GaN layer is 4nm, and the N-polar Al... b Ga 1- b The thickness of the N-layer is 3 nm, and the thickness of the second N-polar GaN layer is 4 nm. N-polar Al layers with different periods... b Ga 1-b In the N layer, the proportion of Al components is the same.

[0080] The p-type GaN layer has a thickness of 150 nm and a Mg doping concentration of 3.5 × 10⁻⁶. 20 cm -3 .

[0081] The method for fabricating the epitaxial wafer of the light-emitting diode in this embodiment includes the following steps: (1) Provide a substrate; (2) A buffer layer is grown on the substrate; Specifically, an AlN layer is grown by PVD as a buffer layer.

[0082] (3) Growing an undoped GaN layer on the buffer layer; Specifically, an undoped GaN layer was grown by MOCVD at a growth temperature of 1120℃ and a growth pressure of 300 torr.

[0083] (4) Growing an N-type GaN layer on an undoped GaN layer; Specifically, an N-type GaN layer was grown by MOCVD at a growth temperature of 1060℃ and a growth pressure of 300 torr.

[0084] (5) Growing an open layer on an N-type GaN layer; Specifically, AlN layers and C / Mg co-doped AlGaN layers were periodically grown on an N-type GaN layer using MOCVD until an open layer was obtained. The growth temperature of the AlN layer was 950℃ and the growth pressure was 200 torr; the growth temperature of the C / Mg co-doped AlGaN layer was 820℃ and the growth pressure was 200 torr.

[0085] (6) The first active layer is grown on the open layer; Specifically, In is grown periodically via MOCVD. x Ga 1-x The process continues with the N-well layer and the first quantum barrier layer until the first active layer is obtained. Wherein... x Ga 1-x The N-well layer was grown at 740℃ under a growth pressure of 200 torr; the first Ga-polar GaN layer was grown at 920℃ under a growth pressure of 200 torr; the Ga-polar Al layer... a Ga 1-a The growth temperature of the N layer is 950℃ and the growth pressure is 200 torr; the growth temperature of the second Ga polar GaN layer is 920℃ and the growth pressure is 200 torr; the growth atmosphere of the first quantum barrier layer is a mixture of H2 and NH3, with a volume ratio of H2 to NH3 of 1:10.

[0086] (7) Grow a second active layer on the first active layer; Specifically, In is grown periodically via MOCVD. y Ga 1-y The process continues with an N-well layer and a second quantum barrier layer until a second active layer is obtained. Wherein... y Ga 1-y The growth temperature of the N-well layer is 760℃ and the growth pressure is 200 torr; the growth temperature of the second Ga polar GaN layer is 920℃ and the growth pressure is 200 torr; the growth atmosphere of the second quantum barrier layer is a mixture of H2 and NH3, with a volume ratio of H2 to NH3 of 1:10.

[0087] Specifically, after the growth of the last third Ga polar GaN layer of the second active layer is completed, it is annealed at 1040°C for 60 min in a mixed gas atmosphere of NH3, H2 and N2; wherein the volume ratio of NH3, H2 and N2 is 3:2:3.

[0088] (8) Grow a third active layer on the second active layer; Specifically, In is grown periodically via MOCVD. z Ga 1-z The process continues with the N-well layer and the third quantum barrier layer until the third active layer is obtained. In... z Ga 1-z The N-well layer was grown at 780℃ under a growth pressure of 300 torr; the first N-polar GaN layer was grown at 840℃ under a growth pressure of 300 torr; the N-polar Al... b Ga 1-b The growth temperature of the N-layer is 860℃ and the growth pressure is 300 torr; the growth temperature of the second N-polar GaN layer is 840℃ and the growth pressure is 300 torr; the growth atmosphere of the third quantum barrier layer is a mixture of N2 and NH3, with a volume ratio of N2 to NH3 of 1:3.

[0089] (9) Grow a P-type GaN layer on the third active layer; Specifically, a P-type GaN layer was grown by MOCVD at a growth temperature of 980℃ and a growth pressure of 250 torr.

[0090] Example 2 This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 1 in that: Along the growth direction of the LED epitaxial wafer, the C doping concentration of the C / Mg co-doped AlGaN layer in different periods decreases, while the Mg doping concentration increases, and the proportion of Al component also increases. Specifically, in the C / Mg co-doped AlGaN layers of the 1st to 6th periods, the C doping concentration is 8.5 × 10⁻⁶. 16 cm -3 7.5×10 16 cm -3 6.5×10 16 cm -3 5.5×10 16 cm -3 4.5×10 16 cm -3 and 3.5×10 16 cm -3 The Mg doping concentrations were 3.5 × 10⁻⁶. 16 cm -3 4.5×10 16 cm -3 5.5×10 16 cm -3 6.5×10 16 cm -37.5×10 16 cm -3 and 8.5×10 16 cm -3 The proportions of Al components were 0.09, 0.10, 0.11, 0.12, 0.13, and 0.14, respectively. It should be noted that in a single-cycle C-Mg co-doped AlGaN layer, the C doping concentration, Mg doping concentration, and the proportion of Al component do not change with thickness.

[0091] Accordingly, in the preparation method of this layer, the flow rates of C source (TMGa), Al source (TMAl), and Mg source (Cp2Mg) are controlled to achieve the regulation of C doping concentration, Al composition, and Mg doping concentration in the C and Mg co-doped AlGaN layer.

[0092] Everything else is the same as in Example 1.

[0093] Example 3 This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 2 in that: Along the growth direction of the LED epitaxial wafer, Ga polar Al in the first active layer of different periods a Ga 1-a The proportion of Al component in the N-layer increases progressively. Specifically, in the Ga polar Al layers of the 1st to 5th periods... a Ga 1-a In the N-layer, the proportions of Al components are 0.06, 0.07, 0.08, 0.09, and 0.1%, respectively. It should be noted that in a single period of Ga polar Al... a Ga 1- a In the N layer, the proportion of Al component does not change with thickness.

[0094] Accordingly, in the preparation method of this layer, Ga polar Al is grown in different cycles. a Ga 1-a In the N-layer configuration, Ga polarity Al is achieved by controlling the flow rate of the Al source (TMAl). a Ga 1-a The proportion of Al components in the N layer is regulated.

[0095] Everything else is the same as in Example 2.

[0096] Example 4 This embodiment provides a light-emitting diode epitaxial wafer, which differs from Embodiment 3 in that: Along the growth direction of the LED epitaxial wafer, the N-polarity Al in the third active layer of different periods b Ga 1-bThe proportion of Al component in the N layer decreases progressively. Specifically, the N-polar Al content decreases in the first to fourth periods. b Ga 1-b In the N layer, the proportions of Al components were 0.14, 0.13, 0.12, and 0.11, respectively.

[0097] It should be noted that in a single cycle, the N polarity Al b Ga 1-b In the N layer, the proportion of Al component does not change with thickness.

[0098] Accordingly, in the preparation method of this layer, N-polar Al is grown in different cycles. b Ga 1-b In the N-layer configuration, N-polarity Al is achieved by controlling the flow rate of the Al source (TMAl). b Ga 1-b The proportion of Al components in the N layer is regulated.

[0099] Everything else is the same as in Example 3.

[0100] Comparative Example 1 This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that: Excluding the open layer.

[0101] Everything else is the same as in Example 1.

[0102] Comparative Example 2 This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that: The third quantum barrier layer of the third active layer has the same composition as the first quantum barrier layer.

[0103] Everything else is the same as in Example 1.

[0104] Comparative Example 3 This comparative example provides a light-emitting diode epitaxial wafer, which differs from Example 1 in that: The first, second, and third quantum barrier layers are all Ga polar GaN layers. The thickness of each of the first, second, and third quantum barrier layers is 10 nm.

[0105] Everything else is the same as in Example 1.

[0106] The LED epitaxial wafers obtained in Examples 1-4 and Comparative Examples 1-3 were fabricated into chips with a vertical structure of 5 mil × 7 mil. The luminous intensity was measured at 120 mA, and the brightness improvement rate of Example 1 was calculated based on the data from Comparative Example 1. Specific results are shown in the table below:

[0107] 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, characterized in that, It includes a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, an opening layer, a first active layer, a second active layer, a third active layer and a P-type GaN layer are sequentially stacked on the substrate. The opening layer comprises alternating layers of AlN and C, Mg co-doped AlGaN; The first active layer includes alternating layers of In x Ga 1-x An N-well layer and a first quantum barrier layer; the first quantum barrier layer comprises N-well layers sequentially stacked on the In... x Ga 1-x The first Ga polar GaN layer on the N-well layer, Ga polar Al a Ga 1-a N-layer and second Ga-polar GaN layer; The second active layer includes alternating layers of In y Ga 1-y The N-well layer and the second quantum barrier layer; the second quantum barrier layer is a third Ga polar GaN layer; The third active layer comprises alternating layers of In z Ga 1-z An N-well layer and a third quantum barrier layer; the third quantum barrier layer comprises layers sequentially stacked on top of the In... z Ga 1-z The first N-polar GaN layer on the N-well layer, and the N-polar Al b Ga 1-b N-layer and second N-polar GaN layer; Where x ranges from 0.18 to 0.3, y ranges from 0.1 to 0.2, z ranges from 0.25 to 0.4, a ranges from 0.05 to 0.1, and b ranges from 0.08 to 0.15; and y < x < z, a ≤ b.

2. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, Along the growth direction of the light-emitting diode epitaxial wafer, the C doping concentration of the C and Mg co-doped AlGaN layer in the opening layers of different periods decreases, the Mg doping concentration increases, and the proportion of Al component increases.

3. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, Along the growth direction of the light-emitting diode epitaxial wafer, the Ga polar Al in the first active layer of different periods a Ga 1-a The proportion of Al components in the N layer increases progressively.

4. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, Along the growth direction of the epitaxial wafer of the light-emitting diode, the N-polarity Al in the third active layer of different periods b Ga 1-b The proportion of Al component in the N layer decreases.

5. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The number of periods of the opening layer is 3 to 8; The thickness of the AlN layer is 3nm~5nm; The thickness of the C and Mg co-doped AlGaN layer is 3 nm to 5 nm, and the C doping concentration is 1 × 10⁻⁶. 16 cm -3 ~1×10 17 cm -3 The Mg doping concentration is 1×10 16 cm -3 ~1×10 17 cm -3 Its Al component accounts for 0.05~0.2%.

6. The light-emitting diode epitaxial wafer as described in claim 1, characterized in that, The number of cycles in the first active layer is 3 to 12; The In x Ga 1-x The thickness of the N-well layer is 2nm~3.5nm; The thickness of the first Ga polar GaN layer is 2nm~5nm; The Ga polar Al a Ga 1-a The thickness of the N layer is 1nm~4nm; The thickness of the second Ga polar GaN layer is 2nm~5nm; The number of periods in the second active layer is 3 to 12; The In y Ga 1-y The thickness of the N-well layer is 2nm~3.5nm; The thickness of the third Ga polar GaN layer is 8nm~15nm; The number of cycles in the third active layer is 3 to 12; The In z Ga 1-z The thickness of the N-well layer is 2nm~5nm; The thickness of the first N-polar GaN layer is 2nm~5nm; The N polarity Al b Ga 1-b The thickness of the N layer is 1nm~4nm; The thickness of the second N-polar GaN layer is 2nm~5nm.

7. A method for fabricating a light-emitting diode epitaxial wafer, used to fabricate a light-emitting diode epitaxial wafer as described in any one of claims 1 to 6, characterized in that, include: Provide substrate; A buffer layer, an undoped GaN layer, an N-type GaN layer, an opening layer, a first active layer, a second active layer, a third active layer, and a P-type GaN layer are sequentially grown on the substrate. The opening layer comprises alternating layers of AlN and C, Mg co-doped AlGaN; The first active layer includes alternating layers of In x Ga 1-x An N-well layer and a first quantum barrier layer; the first quantum barrier layer comprises N-well layers sequentially stacked on the In... x Ga 1-x The first Ga polar GaN layer on the N-well layer, Ga polar Al a Ga 1-a N-layer and second Ga-polar GaN layer; The second active layer includes alternating layers of In y Ga 1-y The second quantum barrier layer is an N-well layer and a second quantum barrier layer; the second quantum barrier layer is a third Ga polar GaN layer; after the growth of the last third Ga polar GaN layer of the second active layer is completed, it is annealed at 1000℃~1100℃ for 40min~100min in a mixed gas atmosphere of NH3, H2 and N2. The third active layer comprises alternating layers of In z Ga 1-z An N-well layer and a third quantum barrier layer; the third quantum barrier layer comprises layers sequentially stacked on top of the In... z Ga 1-z The first N-polar GaN layer on the N-well layer, and the N-polar Al b Ga 1-b N-layer and second N-polar GaN layer; Where y < x < z, a ≤ b.

8. The method for fabricating a light-emitting diode epitaxial wafer as described in claim 7, characterized in that, The growth temperature of the AlN layer is 900℃~1100℃, and the growth pressure is 100 torr~300 torr. The growth temperature of the C and Mg co-doped AlGaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr.

9. The method for fabricating a light-emitting diode epitaxial wafer as described in claim 7, characterized in that, The In x Ga 1-x The growth temperature of the N-well layer is 730℃~800℃, and the growth pressure is 100 torr~300 torr. The growth temperature of the first Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the Ga polar Al a Ga 1-a The growth temperature of the N layer is 870℃~1000℃, and the growth pressure is 100 torr~300 torr; the growth temperature of the second Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the growth atmosphere of the first quantum barrier layer is a mixture of H2 and NH3, and the volume ratio of H2 to NH3 is 1:8~1:

12. The In y Ga 1-y The growth temperature of the N-well layer is 740℃~810℃, and the growth pressure is 100 torr~300 torr; The growth temperature of the third Ga polar GaN layer is 850℃~950℃, and the growth pressure is 100 torr~300 torr; the growth atmosphere of the second quantum barrier layer is a mixture of H2 and NH3, and the volume ratio of H2 to NH3 is 1:8~1:

12. The In z Ga 1-z The growth temperature of the N-well layer is 750℃~800℃, and the growth pressure is 100 torr~300 torr. The growth temperature of the first N-polar GaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr; The N polarity Al b Ga 1-b The growth temperature of the N layer is 820℃~900℃, and the growth pressure is 100 torr~300 torr; The growth temperature of the second N-polar GaN layer is 800℃~900℃, and the growth pressure is 100 torr~300 torr; The growth atmosphere of the third quantum barrier layer is a mixture of N2 and NH3, with a volume ratio of N2 to NH3 of 1:1 to 1:

5.

10. A light-emitting diode, characterized in that, Includes the light-emitting diode epitaxial wafer as described in any one of claims 1 to 6.

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