A method for manufacturing LEDs with improved luminous efficiency

Abstract

The present application discloses a method for manufacturing an LED for improving luminous efficiency, comprising the steps of: depositing an Al2O3 transition layer on the surface of a sapphire substrate; paving polystyrene microspheres; sputtering an AlN layer; performing annealing in a temperature gradient manner so that the polystyrene microspheres are all transformed into hollow spherical shells; and growing an n-type semiconductor layer, a multi-quantum well layer, and a P-type semiconductor layer. The present invention can effectively improve the luminous efficiency and luminous intensity of an LED chip.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and more specifically, to a method for manufacturing an LED for improving luminous efficiency. Background Art

[0002] Nowadays, LED (Light Emitting Diode) has replaced incandescent lamps and fluorescent lamps due to its advantages of energy saving and environmental protection, and is widely used in the lighting field and backlight display field. As LED applications become more and more widespread, the market demand for its brightness is also increasing, especially the luminous efficiency of high-end LED chip products such as deep ultraviolet LED, mini / micro-LED, etc. needs to be improved as soon as possible.

[0003] Therefore, it is urgent to develop new LED manufacturing methods to improve the luminous efficiency of LEDs. Summary of the invention

[0004] The present invention provides a method for manufacturing an LED with improved luminous efficiency, which can effectively improve the luminous efficiency and luminous intensity of an LED chip.

[0005] The present application provides a method for manufacturing an LED for improving luminous efficiency, comprising the following steps:

[0006] Provide sapphire substrate sheets;

[0007] Depositing an Al2O3 transition layer on the surface of the sapphire substrate;

[0008] A plurality of polystyrene microspheres are evenly spin-coated on the surface of the Al2O3 transition layer by a spin-coating method;

[0009] sputtering an AlN layer on the plurality of polystyrene microspheres by PVD, wherein the AlN layer covers the polystyrene microspheres;

[0010] Annealing the sapphire substrate in a temperature gradient manner to remove part of the polystyrene material in the plurality of polystyrene microspheres, so that the plurality of polystyrene microspheres are all transformed into hollow spherical shells, wherein the annealing temperature is controlled to gradually increase from 1300° C. to 1800° C. during the annealing process;

[0011] An n-type semiconductor layer, a multi-quantum well layer and a P-type semiconductor layer are sequentially grown on the surface of the AlN layer by MOCVD to obtain a LED epitaxial wafer with a complete structure.

[0012] Optionally, the thickness of the Al2O3 transition layer is 450-650 nm.

[0013] Optionally, the AlN layer has a thickness of 500-600 nm.

[0014] Optionally, the annealing treatment time is 20 to 40 minutes, and the annealing atmosphere is a nitrogen-oxygen mixed gas.

[0015] Optionally, the diameter of the hollow spherical shell is 260-460 nm, and the distance between two adjacent hollow spherical shells is 210-460 nm.

[0016] Compared with the prior art, the LED manufacturing method for improving luminous efficiency provided by the present invention achieves at least the following beneficial effects:

[0017] (1) The present invention forms a hollow spherical shell between the Al2O3 transition layer and the AlN layer, and the hollow spherical shell can enhance the reflection and refraction of the light from the quantum well light-emitting layer by the LED, thereby reducing the absorption of light and improving the luminous efficiency of the LED. In addition, since the diameter of the hollow spherical shell and the spacing between the hollow spherical shells match the wavelength of deep ultraviolet and low blue light LEDs (210-455nm), when the light emitted from the multi-quantum well light-emitting layer is emitted to the hollow spherical shell, it will encounter a nano-scale window, and the light can oscillate back and forth at both ends of the window. The light of the wavelength matching the window can be enhanced and propagated from the side wall of the hollow spherical shell, effectively improving the luminous intensity of the LED chip, and is particularly suitable for making deep ultraviolet LED chips and low blue light LED chips.

[0018] (2) The present invention deposits an Al2O3 transition layer on the substrate first, which, on the one hand, can play a filling role to make the substrate surface flat. On the other hand, the Al2O3 transition layer can adsorb MO sources to facilitate epitaxial growth. The PVD sputtering AlN layer on the surface of the polystyrene microspheres is used, on the one hand, to fix the polystyrene microspheres, and on the other hand, the AlN layer is used as a buffer layer for subsequent growth to reduce the lattice mismatch between materials.

[0019] (3) The present invention adopts a temperature gradient method to anneal the sapphire substrate. On the one hand, the temperature gradient can fully decompose and volatilize the polystyrene, so that the multiple polystyrene microspheres are transformed into hollow spherical shells. On the other hand, because the surface mobility of Al atoms increases with the temperature gradient, the grain size of AlN will become smaller, the nucleation density of the grains will increase, and further two-dimensional lateral growth will be achieved, and the roughness will be reduced. Under this condition, the AlN thin film layer obtained by epitaxy is the smoothest and brightest, and the crystal quality is also higher, which is conducive to the improvement of the crystal quality of subsequent LED epitaxial materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0021] Figure 1The sapphire substrate, Al2O3 transition layer and polystyrene microspheres of the LED of this application.

[0022] Figure 2 The sapphire substrate, Al2O3 transition layer, polystyrene microspheres, and AlN layer of the LED of this application.

[0023] Figure 3 The figure shows a complete structural diagram of an LED provided in an embodiment of the present application;

[0024] Among them, 1. sapphire substrate, 2. Al2O3 transition layer, 3. polystyrene microspheres, 4. AlN layer, 5. hollow spherical shell, 6. n-type semiconductor layer, 7. multi-quantum well light-emitting layer, 8. P-type semiconductor layer. DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0026] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0027] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0028] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0029] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0030] The present invention provides an LED manufacturing method for improving luminous efficiency, which can effectively improve the luminous efficiency and luminous intensity of LED chips, and is particularly suitable for manufacturing deep ultraviolet LED chips and low blue light LED chips.

[0031] The following is a detailed description with reference to the accompanying drawings and specific embodiments.

[0032] See also Figure 1-Figure 3 , the LED manufacturing method for improving luminous efficiency includes:

[0033] Step 1: Provide a sapphire substrate sheet 1.

[0034] Step 2: Deposit an Al2O3 transition layer 2 on the surface of the sapphire substrate 1 by an atomic layer deposition method, wherein the thickness of the Al2O3 transition layer 2 is 450-650 nm.

[0035] Step 3: Use a spin coating method to evenly spin-coat a plurality of polystyrene microspheres 3 on the surface of the Al2O3 transition layer 2.

[0036] Step 4: sputtering an AlN layer 4 on the multiple polystyrene microspheres 3 by PVD, wherein the AlN layer 4 covers the polystyrene microspheres 3 and has a thickness of 500-600 nm.

[0037] Step 5, annealing the sapphire substrate sheet 1 in a temperature gradient manner to remove part of the polystyrene material in the multiple polystyrene microspheres 3, so that the multiple polystyrene microspheres 3 are all transformed into hollow spherical shells 5, wherein the annealing temperature is controlled to gradually increase from 1300°C to 1800°C during the annealing process, the annealing time is 20 to 40 minutes, and the annealing atmosphere is a nitrogen-oxygen mixture. Optionally, the ratio of nitrogen to oxygen is 6:1 to 2:1.

[0038] Furthermore, the diameter R of the hollow spherical shell 5 is 260-460 nm, and the distance L between two adjacent hollow spherical shells is 210-460 nm.

[0039] Step 6: Using MOCVD to sequentially grow an n-type semiconductor layer 6, a multi-quantum well layer 7 and a P-type semiconductor layer 8 on the surface of the AlN layer 4 to obtain a fully structured LED epitaxial wafer.

[0040] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for manufacturing an LED for improving luminous efficiency, characterized in that: The following steps are involved: Provide sapphire substrate sheets; Depositing an Al2O3 transition layer on the surface of the sapphire substrate; A plurality of polystyrene microspheres are evenly spin-coated on the surface of the Al2O3 transition layer by a spin-coating method; sputtering an AlN layer on the plurality of polystyrene microspheres by PVD, wherein the AlN layer covers the polystyrene microspheres; Annealing the sapphire substrate in a temperature gradient manner to remove part of the polystyrene material in the plurality of polystyrene microspheres, so that the plurality of polystyrene microspheres are all transformed into hollow spherical shells, wherein the annealing temperature is controlled to gradually increase from 1300° C. to 1800° C. during the annealing process; An n-type semiconductor layer, a multi-quantum well layer and a P-type semiconductor layer are sequentially grown on the surface of the AlN layer by MOCVD to obtain a LED epitaxial wafer with a complete structure.

2. The method for manufacturing an LED for improving luminous efficiency according to claim 1, characterized in that: The thickness of the Al2O3 transition layer is 450-650nm.

3. The method for manufacturing an LED for improving luminous efficiency according to claim 1, characterized in that: The thickness of the AlN layer is 500-600 nm.

4. The method for manufacturing an LED for improving luminous efficiency according to claim 1, characterized in that: The annealing treatment time is 20 to 40 minutes, and the annealing atmosphere is a nitrogen and oxygen mixed gas.

5. The method for manufacturing an LED for improving luminous efficiency according to claim 1, characterized in that: The diameter of the hollow spherical shell is 260-460 nm, and the distance between two adjacent hollow spherical shells is 210-460 nm.

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