CN114420800A - Deep ultraviolet LED and preparation method thereof - Google Patents

Deep ultraviolet LED and preparation method thereof Download PDF

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CN114420800A
CN114420800A CN202111492919.3A CN202111492919A CN114420800A CN 114420800 A CN114420800 A CN 114420800A CN 202111492919 A CN202111492919 A CN 202111492919A CN 114420800 A CN114420800 A CN 114420800A
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aln
algan
thin film
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郭康贤
程权炜
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Guangzhou University
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Guangzhou University
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    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
    • H01L33/007—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound comprising nitride compounds
    • H—ELECTRICITY
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    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0093—Wafer bonding; Removal of the growth substrate
    • H—ELECTRICITY
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    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/12—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a stress relaxation structure, e.g. buffer layer
    • H—ELECTRICITY
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    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H01L33/22—Roughened surfaces, e.g. at the interface between epitaxial layers
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
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    • H—ELECTRICITY
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    • H01L2933/0008—Processes
    • H01L2933/0033—Processes relating to semiconductor body packages

Abstract

The invention discloses a preparation method of a deep ultraviolet LED, which comprises the following steps: (1) preparing a GaN film on a SiC substrate; (2) preparing an AlN film on the GaN film prepared in the step (1) to obtain SiC/GaN/AlN; (3) bonding the AlN thin film of SiC/GaN/AlN to the upper surface of the sapphire substrate; (4) stripping the SiC substrate, and then removing the GaN layer by using a membrane separation technology to obtain a sapphire/AlN template substrate; (5) an AlGaN transition layer, an n-AlGaN layer, a quantum well layer, a p-AlGaN film, a p-GaN film and a p-type electrode reflection layer are sequentially grown on the AlN film of the sapphire/AlN template substrate. The invention also discloses the deep ultraviolet LED prepared by the method. The invention solves the problem that more dislocation exists in AlN due to lattice mismatch, and simultaneously improves the light emitting efficiency of the deep ultraviolet LED.

Description

Deep ultraviolet LED and preparation method thereof
Technical Field
The invention relates to the field of deep ultraviolet LEDs, in particular to a deep ultraviolet LED and a preparation method thereof.
Background
Aluminum nitride is used as a direct band gap semiconductor, the forbidden band width is 6.2eV, and the aluminum nitride has wide application prospect in deep ultraviolet electronic devices, and the realization of high-performance LED devices needs a high-quality AlN substrate as a basis. Due to the lack of homogeneous substrates, currently commercialized epitaxy of uv LEDs mostly employs heterogeneous substrates such as silicon, silicon carbide and sapphire. However, silicon has an influence on AlGaN epitaxy due to lattice mismatch and thermal mismatch, and silicon carbide is not suitable for growing AlN because it easily absorbs ultraviolet light of 360nm, while sapphire also has lattice mismatch and thermal mismatch and has an influence on AlGaN epitaxy, but has a rich production experience, hardly absorbs ultraviolet light of 200-400 nm, and is suitable for being used as a substrate for growing AlN, but the problem that many dislocations exist in AlN due to lattice mismatch needs to be solved.
Due to the fact that a large number of dislocations and defects exist in the ultraviolet LED epitaxial layer, crystal quality is poor, the dislocations can extend to the quantum well region to serve as non-radiative recombination centers, and recombination efficiency is reduced. In addition, due to the problems of material refractive index difference and the like, total reflection exists between the chip and the air interface, and the light extraction efficiency of the ultraviolet LED is seriously reduced.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a preparation method of a deep ultraviolet LED, which solves the problem that more dislocations exist in AlN due to lattice mismatch.
The invention also aims to provide the deep ultraviolet LED prepared by the preparation method of the deep ultraviolet LED, and the light extraction efficiency and the intensity are high.
The purpose of the invention is realized by the following technical scheme:
a preparation method of a deep ultraviolet LED comprises the following steps:
(1) preparing a GaN film on a SiC substrate;
(2) preparing an AlN film on the GaN film prepared in the step (1) to obtain SiC/GaN/AlN;
(3) bonding the AlN thin film of SiC/GaN/AlN to the upper surface of the sapphire substrate;
(4) stripping the SiC substrate, and then removing the GaN layer by using a membrane separation technology to obtain a sapphire/AlN template substrate;
(5) an AlGaN transition layer, an n-AlGaN film, a quantum well layer, a p-AlGaN film, a p-GaN film and a p-type electrode reflecting layer are sequentially grown on the AlN film of the sapphire/AlN template substrate.
Preferably, step (5) is preceded by the following steps:
and (4) etching the AlN thin film on the sapphire/AlN template substrate obtained in the step (4) to enable the AlN thin film to be in a periodic columnar structure.
Preferably, the spacing between the AlN pillars of the periodic pillar structure is 6% to 20% of the cross-sectional size of the AlN pillars.
Preferably, the top of the AlN pillar of the periodic pillar structure is a concave hemisphere.
Preferably, the AlGaN transition layer is Al0.3Ga0.7And (6) N thin films.
Preferably, the preparation method of the deep ultraviolet LED further comprises the following steps: and etching the light emergent surface of the sapphire substrate into a hemispherical array structure.
Preferably, the bonding in step (3) is specifically: bonding is performed using atomic diffusion techniques or surface activation techniques.
Preferably, the GaN thin film is prepared by using a metal organic compound chemical vapor phase;
the AlN thin film is prepared by adopting a metal organic compound chemical vapor phase.
Preferably, the stripped SiC substrate specifically includes: and stripping the SiC substrate by adopting a laser stripping technology.
The deep ultraviolet LED prepared by the preparation method of the deep ultraviolet LED comprises a sapphire substrate, an AlN thin film layer, an AlGaN transition layer, an n-AlGaN thin film, a quantum well layer, a p-AlGaN thin film, a p-GaN thin film, a p-type electrode reflection layer, a first welding spot, a second welding spot and a substrate;
the sapphire substrate, the AlN thin film layer, the AlGaN transition layer, the n-AlGaN thin film, the quantum well layer, the p-AlGaN thin film, the p-GaN thin film and the p-type electrode reflection layer are sequentially laminated;
the p-type electrode reflecting layer is connected with the substrate through the first welding point and the first bonding pad in sequence;
the n-AlGaN layer is connected with the substrate through a second welding point and a second bonding pad in sequence.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) firstly, preparing a GaN film on a SiC substrate, and then preparing an AlN film on the GaN film; the preparation method comprises the steps of preparing a GaN film with good quality, enabling the lattice matching degree of GaN and AlN to be high, and in order to reduce lattice mismatch between sapphire and AlN, growing AlN crystals with few defects on GaN, bonding an AlN surface of SiC/GaN/AlN to the upper surface of a sapphire substrate through an atomic diffusion technology, a surface activation technology or other bonding technologies, enabling the AlN crystal and the AlN to be well combined under the condition of good quality, greatly improving the quality of sapphire and AlN, removing a SiC layer through a laser stripping technology, removing a GaN layer through a film separation technology, and finally obtaining a sapphire/AlN template substrate to provide a good growth substrate for later-stage growth of the n-AlGaN film.
(2) The invention etches the AlN film to ensure that the AlN film becomes a periodic columnar structure, so that dislocation is stopped on the surface of AlN, the dislocation of the n-AlGaN film grown in the later period is reduced, the crystal quality is improved, and the stress generated by the n-AlGaN film can be relieved. In addition, in order to maximize the utilization of light transmitted through the AlN pillar, the top is etched into a concave hemispherical structure using an etching technique to increase the intensity of light and the light extraction efficiency.
(3) The columnar structure of the AlN thin film can be used as a transverse Bragg reflector, can enhance the reflection, refraction and interference of light, on one hand, enhances the intensity of the light and increases the emergence rate, on the other hand, reduces the probability of light emergence from the side surface, and leads the light to be more emergent from the substrate side.
(4) The AlGaN transition layer is filled in the AlN etching layer, can be better matched with an AlN film, minimizes the number of dislocation, prepares the transition layer with a certain thickness and the same components when reaching the top of AlN, and then grows the n-AlGaN film with a certain thickness upwards, so that the lattice mismatch between AlN and n-AlGaN is smaller; the dislocation is reduced, and the quality of the n-AlGaN film is improved.
(5) The deep ultraviolet LED adopts a flip chip mode, directly transfers heat to the substrate through the welding spot and then transfers the heat to the outside, and can enhance the heat dissipation effect.
(6) According to the deep ultraviolet LED, the sapphire substrate is patterned into the hemispherical array, and the light-emitting intensity is enhanced due to the focusing of light.
Drawings
Fig. 1 is a schematic view of a deep ultraviolet LED prepared according to an embodiment of the present invention. In the figure, 1 is a sapphire substrate, 2 is an AlN thin film, 3 is an AlGaN transition layer, 4 is an n-AlGaN layer, 5 is a quantum well layer, 6 is a p-AlGaN thin film, and 7 is a p-GaN thin film; 8 is a p-type electrode reflection layer, 9-1 is a first welding point, 10-1 is a first welding pad, 9-2 is a second welding point, 10-2 is a second welding point, and 11 is a substrate.
Fig. 2 is a schematic flow chart of steps (1) to (4) of the method for manufacturing a deep ultraviolet LED according to the embodiment of the present invention. In the figure, 1 is a sapphire substrate, 12 is a SiC substrate, 13 is a GaN thin film, and 2 is an AlN thin film.
Fig. 3 is a schematic flow chart of steps (4) — (7) of the method for manufacturing a deep ultraviolet LED according to the embodiment of the present invention. In the figure, 1 is a sapphire substrate, 2 is an AlN thin film, 3 is an AlGaN transition layer, 4 is an n-AlGaN thin film, 5 is a quantum well layer, 6 is a p-AlGaN thin film, and 7 is a p-GaN thin film; 8 is a p-type electrode reflection layer, 9-1 is a first welding point, 10-1 is a first welding pad, 9-2 is a second welding point, 10-2 is a second welding point, and 11 is a substrate.
Fig. 4 is a graph of light extraction efficiency of the epitaxial wafers a to E in an example of the present invention.
Fig. 5(a) and 5(b) are graphs showing electric field intensity distributions of TE and TM optical modes of the epitaxial wafer a in the example of the present invention, respectively.
Fig. 6(a) and 6(B) are graphs showing electric field intensity distributions of TE and TM optical modes of the epitaxial wafer B in the embodiment of the present invention, respectively.
Fig. 7(a) and 7(b) are graphs of the electric field intensity distribution of the TE and TM optical modes of the epitaxial wafer C in the embodiment of the present invention, respectively.
Fig. 8(a) and 8(b) are graphs of the electric field intensity distribution of the TE and TM optical modes of the epitaxial wafer D in the example of the present invention, respectively.
Fig. 9(a) and 9(b) are graphs of electric field intensity distribution of TE and TM optical modes of the epitaxial wafer E in the example of the present invention, respectively.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.
Examples
As shown in fig. 1, the deep ultraviolet LED prepared by the method for preparing a deep ultraviolet LED of the present embodiment includes a sapphire substrate, an AlN thin film layer, an AlGaN transition layer, an n-AlGaN thin film, a quantum well layer, a p-AlGaN thin film, a p-GaN thin film, a p-type electrode reflection layer, a first solder joint, a second solder joint, and a substrate; the sapphire substrate, the AlN thin film layer, the AlGaN transition layer, the n-AlGaN thin film, the quantum well layer, the p-AlGaN thin film, the p-GaN thin film and the p-type electrode reflection layer are sequentially laminated; the p-type electrode reflecting layer is connected with the substrate through the first welding point and the first bonding pad in sequence; the n-AlGaN film is connected with the substrate through the second welding spot and the second bonding pad in sequence.
As shown in fig. 2 to 3, the method for manufacturing a deep ultraviolet LED of the present embodiment includes the following steps:
(1) preparing a GaN film on a SiC substrate by adopting a metal organic compound chemical vapor phase method;
(2) preparing an AlN film on the GaN film prepared in the step (1) by adopting a metal organic compound chemical vapor phase method to obtain SiC/GaN/AlN;
(3) bonding the AlN film of the SiC/GaN/AlN to the upper surface of the sapphire substrate by adopting an atomic diffusion technology or a surface activation technology;
(4) stripping the SiC substrate, and then removing the GaN layer by using a membrane separation technology to obtain a sapphire/AlN template substrate;
(4) etching the AlN thin film on the sapphire/AlN template substrate obtained in the step (4) by adopting a mask photoetching technology to enable the AlN thin film to be in a periodic columnar structure, so that dislocation of an AlGaN transition layer is reduced, the dislocation is stopped on the surface of AlN, the dislocation of the n-AlGaN thin film grown in the later period is reduced, the crystal quality is improved, and meanwhile, the light extraction efficiency and the intensity are enhanced through the constructive interference effect of a Bragg reflector and the thin film;
in the AlN column of the periodic columnar structure in this embodiment, the distance between adjacent AlN columns of the quadrangular prism is smaller than the average crack distance of the AlGaN transition layer, specifically, 6% to 20% of the side length of the cross section of the AlN column. Therefore, the extension of dislocation of the AlGaN transition layer is blocked at the gap between the columnar AlN, and the AlGaN transition layer with good quality is prepared, so that the stress generated in the subsequent growth process of the n-AlGaN film can be relieved, and the probability of extending the dislocation to the quantum well layer is reduced.
The top of the AlN column of the periodic columnar structure is concave and hemispherical, so that the light emitting efficiency and intensity can be increased;
(5) growing an AlGaN transition layer, an n-AlGaN film, a quantum well layer, a p-AlGaN film, a p-GaN film and a p-type electrode reflecting layer on the AlN film of the sapphire/AlN template substrate in sequence;
in this embodiment, a 360nm light source is adopted, and the corresponding AlGaN transition layer is Al0.3Ga0.7N; in the embodiment, the AlGaN transition layer is filled in the AlN film etching layer, so that the AlN film can be better matched, the number of dislocation is minimized, when reaching the top of AlN, the AlGaN transition layer with a certain thickness grows upwards, and then the n-AlGaN film with a certain thickness grows upwards, so that lattice mismatch between AlN and n-AlGaN is smaller. The dislocation is reduced, and the quality of the n-AlGaN film is improved.
(6) Etching the light-emitting surface of the sapphire substrate into a hemispherical array structure by adopting a mask photoetching technology to obtain an epitaxial chip;
(7) and welding the prepared epitaxial chip to the substrate through a welding process.
Simulation test example:
the test example adopts optical simulation software of finite time domain difference (FDTD) to research the light extraction efficiency and the electric field intensity distribution of TE and TM optical modes of five types of epitaxial wafers of a traditional thin film epitaxial wafer, the AlN layer is subjected to columnar etching, the transition layer is filled in the AlN etching layer, the AlN layer is subjected to columnar etching and AlN columnar body concave semicircle etching, the AlN layer is etched, and sapphire is subjected to convex semicircle etching.
Simulation setting:
(1) simulation dimension: 2D;
(2) a simulation area: 5.15 μm by 5.15 μm;
(3) a power monitor: 5, 4 surrounding light sources, 1 is positioned at a position 0.15 mu m away from the light emitting surface side of the chip;
(4) boundary conditions: the upper part, the lower part, the left part and the right part are both PML perfect absorbing layers;
(5) a dipole light source: the light emission wavelength is 360nm
Basic parameters of the epitaxial wafer:
(1) size: 3 μm by 4.35 μm
(2) Basic composition (thickness, refractive index, extinction coefficient):
al film: 100nm, 0.4, 4.37
p-GaN thin film: 100nm, 2.7, 0.3
p-AlGaN film: 50nm, 2.6 and 0
Quantum well layer: 100nm, 2.67, 0
n-AlGaN film: 1 μm, 2.6, 0
6、Al0.3Ga0.7N transition layer: 400nm, 2.48 and 0
An AlN thin film: 1 μm, 2.05, 0
Sapphire substrate: 2 μm, 1.79, 0
Epitaxial wafer volume parameters:
an epitaxial wafer A: a conventional thin film type epitaxial wafer; the solar cell sequentially comprises a sapphire substrate, an AlN thin film (not etched), an n-AlGaN thin film, a quantum well layer, a p-AlGaN thin film, a p-GaN thin film and an Al thin film;
an epitaxial wafer B: the AlN layer etching type epitaxial wafer sequentially comprises a sapphire substrate, an etching AlN thin film, an n-AlGaN thin film, a quantum well layer, a p-AlGaN thin film, a p-GaN thin film and an Al thin film, wherein the side length of AlN columnar bodies of the etching AlN thin film is 300nm, the interval is 60nm, and 8 AlN columnar bodies are formed in total. Meanwhile, an n-AlGaN film of 200nm grows in the gaps of the AlN columnar bodies.
An epitaxial wafer C: the AlN etching layer is filled with a transition layer type epitaxial wafer and sequentially comprises a sapphire substrate, an etched AlN thin film, a transition layer, an n-AlGaN thin film, a quantum well layer, a p-AlGaN thin film, a p-GaN thin film and an Al thin film; etching the AlN thin film to be the same as that in the epitaxial wafer B; the transition layers include 200nm AlGaN transition layers grown in the AlN pillar gaps and 200nm AlGaN transition layers grown over the top of the AlN pillars.
An epitaxial wafer D: the AlN layer etching and AlN columnar body concave semicircle etching type epitaxial wafer has the same characteristics as those of the epitaxial wafer B except the following characteristics: etching a concave semicircle at the top of the AlN columnar body; the radius of the concave semicircle is 150nm, and a total of 7 etching parts are formed.
An epitaxial wafer E: the AlN layer etching, the AlN columnar body concave semicircle etching and the sapphire convex semicircle etching type epitaxial wafer have the same characteristics as those of the epitaxial wafer D except the following characteristics: and etching a hemispherical array structure on the light-emitting surface of the sapphire, wherein the radius of each sapphire convex semicircle is 300nm, and the total number of the sapphire convex semicircles is 5.
And (4) conclusion:
fig. 4 is a graph of light extraction efficiency of the epitaxial wafer a, the epitaxial wafer B, the epitaxial wafer C, the epitaxial wafer D, and the epitaxial wafer E, and it can be seen that the light extraction efficiency of the whole epitaxial wafer is higher than that of the conventional thin film type epitaxial wafer through AlN etching, concave semicircle etching of AlN columnar bodies, or sapphire etching. The TE mode is improved by 1.4 to 19.1 percent and the TM mode is improved by 11.8 to 29.3 percent.
As shown in fig. 5(a) -5 (B) and fig. 6(a) -6 (B), it can be seen that the TE light mode of the epitaxial wafer B increases the intensity of the emitted light in the vertical direction by 6.74% compared to the epitaxial wafer a due to the interference of light in the directions of 0 °, 10 °, 30 ° and 40 °. The TM light mode obviously emits light from the initial two sides and passes through the Bragg reflector, so that the light is obviously increased within the range of 10-40 degrees of light-emitting angle, and the light extraction efficiency is improved.
As shown in fig. 6(a) -6 (B) and fig. 7(a) -7 (B), it can be seen that the transition layer is grown in the gap between the AlN pillars and on the surface of the AlN film, and although the transition layer can better match the AlN film and the n-AlGaN, this will increase the material interface, making the total reflection more severe, so the light extraction rate of the epitaxial wafer C will be lower or less affected than that of the epitaxial wafer B, but is almost the same as or even higher than that of the epitaxial wafer a, because the effect of the AlN film etching on improving the light extraction efficiency is greater than or equal to the effect of the transition layer on total reflection, so that the transition layer can reduce the lattice mismatch between the AlN film and the n-AlGaN while the light extraction efficiency is reduced or unchanged, making the performance of the epitaxial wafer better.
As shown in fig. 6(a) -6 (B) and 8(a) -8 (B), since the transition layer only plays a role in matching the n-AlGaN thin film and the AlN thin film, and the influence on light extraction and light extraction intensity is not great, the epitaxial wafer D is formed by adding a semicircular etching means to the epitaxial wafer B, on one hand, the dislocation of the n-AlGaN thin film grown in a semicircular structure can be terminated on the surface, so that the epitaxial quality is better, and on the other hand, the light is more converged in the direction of the light extraction angle of 30 ° due to the semicircular structure. Because the n-AlGaN film is grown only in the semicircle, the component of the n-AlGaN film is the same as that of the n-AlGaN film grown on the surface of the AlN film, and no other interface exists, the light extraction efficiency is almost the same as that of the epitaxial wafer B, but the emergent light intensity is obviously improved due to the convergence effect of the semicircle on light. For the TE mode, the intensity of the emitted light is increased by 23.86%, and for the TM mode, the intensity of the emitted light is increased by 10.94%.
As shown in fig. 6(a) -6 (B) and 9(a) -9 (B), the epitaxial wafer E is formed by adding a sapphire semicircle on the basis of the epitaxial wafer D, and it can be seen that the light extraction efficiency of the TE and TM light modes is significantly improved, and the light extraction efficiency of the epitaxial wafer E is improved by 10.85% and the TM light mode is improved by 10.20% compared with the TE light mode of the epitaxial wafer B. In addition to the improvement of light extraction efficiency, the light extraction intensity is also improved, and the light intensity of the epitaxial wafer E is improved by 42.78% and the TM light mode is improved by 47.18% compared with the TE light mode of the epitaxial wafer B.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (10)

1. A preparation method of a deep ultraviolet LED is characterized by comprising the following steps:
(1) preparing a GaN film on a SiC substrate;
(2) preparing an AlN film on the GaN film prepared in the step (1) to obtain SiC/GaN/AlN;
(3) bonding the AlN thin film of SiC/GaN/AlN to the upper surface of the sapphire substrate;
(4) stripping the SiC substrate, and then removing the GaN layer by using a membrane separation technology to obtain a sapphire/AlN template substrate;
(5) an AlGaN transition layer, an n-AlGaN film, a quantum well layer, a p-AlGaN film, a p-GaN film and a p-type electrode reflecting layer are sequentially grown on the AlN film of the sapphire/AlN template substrate.
2. The method for preparing the deep ultraviolet LED substrate according to claim 1, characterized in that the following steps are further carried out before the step (5):
and (4) etching the AlN thin film on the sapphire/AlN template substrate obtained in the step (4) to enable the AlN thin film to be in a periodic columnar structure.
3. The method according to claim 2, wherein the distance between the AlN posts of the periodic columnar structure is 6-20% of the cross-sectional dimension of the AlN posts.
4. The method according to claim 1 or 3, wherein the top of the AlN pillar of the periodic columnar structure is a concave hemisphere.
5. The method according to claim 1, wherein the AlGaN transition layer is Al0.3Ga0.7And (6) N thin films.
6. The method of claim 1, further comprising the steps of: and etching the light emergent surface of the sapphire substrate into a hemispherical array structure.
7. The method for preparing the deep ultraviolet LED according to claim 1, wherein the bonding in the step (3) is specifically: bonding is performed using atomic diffusion techniques or surface activation techniques.
8. The method according to claim 1, wherein the GaN thin film is prepared by chemical vapor deposition of metal organic compound;
the AlN thin film is prepared by adopting a metal organic compound chemical vapor phase.
9. The method for preparing the deep ultraviolet LED according to claim 1, wherein the peeling of the SiC substrate is specifically: and stripping the SiC substrate by adopting a laser stripping technology.
10. The deep ultraviolet LED prepared by the preparation method of the deep ultraviolet LED according to any one of claims 1 to 9, which is characterized by comprising a sapphire substrate, an AlN thin film layer, an AlGaN transition layer, an n-AlGaN thin film, a quantum well layer, a p-AlGaN thin film, a p-GaN thin film, a p-type electrode reflecting layer, a first welding spot, a second welding spot and a substrate;
the sapphire substrate, the AlN thin film layer, the AlGaN transition layer, the n-AlGaN thin film, the quantum well layer, the p-AlGaN thin film, the p-GaN thin film and the p-type electrode reflection layer are sequentially laminated;
the p-type electrode reflecting layer is connected with the substrate through the first welding point and the first bonding pad in sequence;
the n-AlGaN layer is connected with the substrate through a second welding point and a second bonding pad in sequence.
CN202111492919.3A 2021-12-08 2021-12-08 Deep ultraviolet LED and preparation method thereof Pending CN114420800A (en)

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CN103730549A (en) * 2014-01-07 2014-04-16 大连理工大学 SiC-substrate-based perpendicular structural GaN-based ultraviolet LED (Light Emitting Diode) and production method thereof
CN106784228A (en) * 2017-01-12 2017-05-31 西安电子科技大学 Nonpolar a faces AlN films based on r faces SiC graph substrates and preparation method thereof
CN108878595A (en) * 2017-05-08 2018-11-23 中国科学院苏州纳米技术与纳米仿生研究所 Substrate, semiconductor devices and substrate preparation method
CN110676357A (en) * 2019-08-28 2020-01-10 南京南邮信息产业技术研究院有限公司 Ultra-thin structure deep ultraviolet LED and preparation method thereof
CN113380933A (en) * 2021-05-28 2021-09-10 西安交通大学 Deep ultraviolet LED device with n-AlGaN layer nano porous structure and manufacturing method thereof

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CN103730549A (en) * 2014-01-07 2014-04-16 大连理工大学 SiC-substrate-based perpendicular structural GaN-based ultraviolet LED (Light Emitting Diode) and production method thereof
CN106784228A (en) * 2017-01-12 2017-05-31 西安电子科技大学 Nonpolar a faces AlN films based on r faces SiC graph substrates and preparation method thereof
CN108878595A (en) * 2017-05-08 2018-11-23 中国科学院苏州纳米技术与纳米仿生研究所 Substrate, semiconductor devices and substrate preparation method
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