A method for manufacturing a red light LED based on GaN epitaxy

Abstract

The application discloses a kind of red light LED manufacturing method based on GaN epitaxy, gallium nitride epitaxial wafer is grown on the aluminum oxide substrate of chip, substrate has insulation;Light-emitting part is GaN, its operating voltage is consistent with the operating voltage of blue-green light, facilitate circuit design when red light LED and blue-green light LED combination use;According to preset angle, etching is carried out to epitaxial buffer layer and epitaxial wafer, obtain gallium nitride focusing layer, prepare black layer on the side wall of substrate, can reduce the proportion of side light leakage, and through gallium nitride focusing layer can make blue light focus, to reduce the proportion of blue light emission to side wall black layer, improve light efficiency;Red light conversion material is coated in black layer outside and substrate far from epitaxial wafer one end, can convert blue light into red light, to obtain red light LED chip, improve the overall performance of red light LED, and facilitate red light LED and blue-green light LED combination use.

Description

[0001] The present application is a divisional application of the patent application No. 202110931119.0, with the application date of August 13, 2021, and the title of "Red LED chip and manufacturing method thereof", which is the parent application. TECHNICAL FIELD

[0002] The present application relates to the technical field of LED manufacturing, in particular to a red LED manufacturing method based on GaN epitaxy. BACKGROUND

[0003] The current manufacturing method of red LED generally uses GaAs (gallium arsenide) substrate and AlInGaP (aluminum indium gallium phosphorus) four-element structure epitaxy, while sapphire (aluminum oxide) substrate is used for blue-green light, and GaN (gallium nitride) is the main body of the compound structure.

[0004] The traditional red light manufacturing technology has the defects of low starting voltage, low reverse cut-off voltage, no insulation of the substrate, unable to directly manufacture flip-chip, insufficient mechanical properties of the material itself, high pollution in the manufacturing process, and high risk of using raw materials (arsenic), etc. And the existing red LED chip and blue-green LED chip have great differences in structure and used materials, which leads to many inconveniences in the general use of red LED chip, especially in the combination with blue-green LED, thereby affecting the overall performance of the final device. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a red LED manufacturing method based on GaN epitaxy, which can improve the overall performance of the red LED and facilitate the combination of the red LED with the blue-green LED.

[0006] In order to solve the above technical problems, the technical scheme adopted by the present application is:

[0007] A red LED manufacturing method based on GaN epitaxy, comprising the steps of:

[0008] Growing a gallium nitride epitaxial wafer on an aluminum oxide substrate of a chip;

[0009] Etching the epitaxial wafer and the epitaxial buffer layer between the substrate and the epitaxial wafer according to a preset angle to obtain a gallium nitride focusing layer;

[0010] Dividing the chip and preparing a blackening layer on the sidewall of the substrate;

[0011] Coating a red light conversion material outside the blackening layer and at one end of the substrate away from the epitaxial wafer to form a conversion layer, thereby obtaining a red LED chip.

[0012] In order to solve the above technical problems, the application adopts another technical scheme:

[0013] A red light LED chip comprises an alumina substrate, a gallium nitride focusing layer, a blackening layer and a conversion layer:

[0014] The gallium nitride focusing layer is located at one end of the alumina substrate and comprises an epitaxial wafer with a preset angle inclined surface and an epitaxial buffer layer, and the epitaxial buffer layer is located between the epitaxial wafer and the substrate.

[0015] The blackening layer is located on the sidewall of the substrate.

[0016] The conversion layer is located outside the blackening layer and at the end of the substrate away from the gallium nitride focusing layer.

[0017] The application has the advantages that: the gallium nitride epitaxial wafer is grown on the alumina substrate of the chip, and the substrate has insulation; the light emitting part is GaN, and the working voltage is consistent with that of the GaN blue-green light, facilitating circuit design when the red light LED is combined with the blue-green light LED; the epitaxial buffer layer and the epitaxial wafer are etched according to the preset angle to obtain the gallium nitride focusing layer, the blackening layer is prepared on the sidewall of the substrate, the proportion of side blue light leakage can be reduced, the blue light can be focused through the gallium nitride focusing layer, the scattering of the blue light source to both sides is prevented, the proportion of the emission to the sidewall blackening layer is reduced, and the light emission efficiency is improved; the red light conversion material is coated outside the blackening layer and at the end of the substrate away from the epitaxial wafer, the blue light can be converted into red light, the red light LED chip is obtained, the overall performance of the red light LED is improved, and the red light LED is convenient to combine with the blue-green light LED. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a flow chart of a red light LED manufacturing method based on GaN epitaxy for the embodiment of the application;

[0019] Figure 2 It is a structural schematic diagram of a red light LED chip for the embodiment of the application;

[0020] Figure 3 It is a gallium nitride focusing layer schematic diagram of a red light LED manufacturing method based on GaN epitaxy for the embodiment of the application;

[0021] REFERENCE NUMERALS:

[0022] 1, electrode coating light leakage prevention layer; 2, reflective film focusing layer; 3, gallium nitride focusing layer; 4, blackening layer; 5, isolation layer; 6, conversion layer; 7, protective layer; 8, epitaxial buffer layer; 9, epitaxial layer; 10, alumina substrate; 11, first angle inclined surface; 12, second angle inclined surface. DETAILED DESCRIPTION

[0023] To describe the technical solutions in the present application in detail, realize the purposes and effects, the following will be described in conjunction with the embodiments and the accompanying drawings.

[0024] Please refer to Figure 1 and Figure 3 The embodiment of the present application provides a red light LED manufacturing method based on GaN epitaxy, comprising the steps of:

[0025] Growing a gallium nitride epitaxial wafer on an aluminum oxide substrate of a chip;

[0026] Etching the epitaxial wafer and an epitaxial buffer layer between the substrate and the epitaxial wafer at a preset angle to obtain a gallium nitride focusing layer;

[0027] Segmenting the chip and preparing a blackening layer on the sidewall of the substrate;

[0028] Coating a red light conversion substance on the blackening layer and one end of the substrate away from the epitaxial wafer to form a conversion layer, thereby obtaining a red light LED chip.

[0029] From the above description, the beneficial effects of the present application are that: a gallium nitride epitaxial wafer is grown on an aluminum oxide substrate of a chip, and the substrate has insulation; the light-emitting part is GaN, and its working voltage is consistent with that of GaN blue-green light, which facilitates circuit design when the red light LED is combined with the blue-green light LED; the epitaxial buffer layer and the epitaxial wafer are etched at a preset angle to obtain a gallium nitride focusing layer, and a blackening layer is prepared on the sidewall of the substrate, which can reduce the proportion of side blue light leakage, and the gallium nitride focusing layer can focus the blue light to prevent the blue light source from scattering to both sides, thereby reducing the proportion of emission to the sidewall blackening layer and improving the light-emitting efficiency; the red light conversion substance is coated on the blackening layer and one end of the substrate away from the epitaxial wafer, which can convert the blue light into red light, thereby obtaining a red light LED chip, improving the overall performance of the red light LED, and facilitating the combination of the red light LED with the blue-green light LED.

[0030] Further, the etching of the epitaxial wafer and the epitaxial buffer layer between the substrate and the epitaxial wafer at a preset angle to obtain a gallium nitride focusing layer comprises:

[0031] Etching a bevel with a horizontal included angle of a first angle on the epitaxial buffer layer and etching a bevel with a horizontal included angle of a second angle on the epitaxial wafer, the first angle being smaller than the second angle;

[0032] After etching, two bevels with different angles and in series are formed to obtain a gallium nitride focusing layer.

[0033] As can be seen from the above description, the inclined surface with the first angle is etched on the epitaxial buffer layer, and the inclined surface with the second angle is etched on the epitaxial wafer, thereby forming a continuous combination of different angle slopes, so that the total reflection of this part can be reduced; meanwhile, the combination of the two different angle slopes forms an effect similar to a circular light collecting bowl, which is more conducive to light collection than a single slope.

[0034] Further, the obtaining of the gallium nitride focusing layer comprises:

[0035] According to the shape of the gallium nitride focusing layer, glue coating, exposure, development and evaporation are performed at one end of the gallium nitride focusing layer away from the substrate, so as to obtain a reflective focusing layer;

[0036] At one end of the reflective focusing layer away from the gallium nitride focusing layer, evaporation is performed in a preset material sequence to obtain an electrode-coated light leakage prevention layer, and the electrode-coated light leakage prevention layer is used as a contact electrode during welding with a substrate.

[0037] Photoetching is performed at the edge of the substrate away from one end of the gallium nitride focusing layer to obtain an isolation layer.

[0038] As can be seen from the above description, the reflective focusing layer in combination with the gallium nitride focusing surface can prevent the scattering of blue light sources to both sides; the electrode-coated layer can prevent light leakage of the reflective focusing layer and has the welding combination capability with the substrate; and the isolation layer can prevent the escape of blue light from the edge, leaving only the central part for light emission.

[0039] Further, the splitting of the chip and the preparation of a blackening layer on the sidewall of the substrate comprise:

[0040] The chip is split by using a laser to move the laser focal point from one end of the substrate close to the isolation layer to one end of the substrate close to the epitaxial wafer, and a blackening layer is formed on the sidewall of the substrate during laser splitting.

[0041] As can be seen from the above description, when the chip is split by using a laser, a blackening layer is formed on the sidewall of the substrate, which can reduce side blue light leakage by laser blackening and avoid color deviation.

[0042] Further, the coating of the red light conversion substance on the outside of the blackening layer and one end of the substrate away from the epitaxial wafer to form a conversion layer comprises:

[0043] Red fluorescent powder is added to a silica gel matrix to obtain a red light conversion substance in the form of quantum dots;

[0044] The red light conversion substance is coated on the outside of the blackening layer and one end of the substrate away from the epitaxial wafer to form a conversion layer, and a protective layer is deposited on the surface of the conversion layer.

[0045] From the above description, the red light conversion material is coated in a full-coverage form above the substrate and on the side of the blackening layer, which can convert blue light into red light and avoid blue light leakage; and the conversion layer is fully wrapped by the deposition of the protective layer, which can reduce the attenuation and aging of the conversion layer.

[0046] Please refer to Figure 2 Another embodiment of the present application provides a red LED chip, comprising an aluminum oxide substrate, a gallium nitride focusing layer, a blackening layer and a conversion layer.

[0047] The gallium nitride focusing layer is located at one end of the aluminum oxide substrate and comprises an epitaxial wafer with a preset angle inclined surface and an epitaxial buffer layer, which is located between the epitaxial wafer and the substrate.

[0048] The blackening layer is located on the sidewall of the substrate.

[0049] The conversion layer is located outside the blackening layer and at the end of the substrate away from the gallium nitride focusing layer.

[0050] From the above description, the gallium nitride epitaxial wafer is grown on the aluminum oxide substrate of the chip, and the substrate has insulation; the light-emitting part is GaN, which has the same working voltage as the GaN blue-green light, facilitating the circuit design when the red LED is combined with the blue-green LED; the gallium nitride focusing layer is obtained through the epitaxial buffer layer and the epitaxial wafer with a preset angle inclined surface, and the blackening layer is provided on the sidewall of the substrate, which can reduce the proportion of side blue light leakage, and the gallium nitride focusing layer can focus the blue light to prevent the blue light source from scattering to both sides, thereby reducing the proportion of emission to the sidewall blackening layer and improving the light efficiency; the conversion layer is located outside the blackening layer and at the end of the substrate away from the epitaxial wafer, which can convert blue light into red light to obtain a red LED chip, improve the overall performance of the red LED, and facilitate the combination of the red LED with the blue-green LED.

[0051] Further, the epitaxial wafer has a first angle inclined surface, and the epitaxial buffer layer has a second angle inclined surface, and the first angle is smaller than the second angle.

[0052] The epitaxial wafer and the epitaxial buffer layer form two different angle and continuous inclined surfaces.

[0053] From the above description, since the first angle is smaller than the second angle and the continuous combination of different angle inclined surfaces is formed, the total reflection of this part can be reduced; at the same time, the combination of two different angle inclined surfaces forms an effect similar to a circular light collecting bowl, which is more conducive to light collection than a single inclined surface.

[0054] Further, it further comprises a reflection focusing layer, an electrode-coated anti-leakage layer and an isolation layer.

[0055] The reflective focusing layer is located at one end of the gallium nitride focusing layer away from the substrate.

[0056] The electrode-coated light leakage prevention layer is located at one end of the reflective focusing layer away from the gallium nitride focusing layer.

[0057] The isolation layer is located at the edge of the substrate away from one end of the gallium nitride focusing layer.

[0058] As can be seen from the above description, the reflective focusing layer in combination with the gallium nitride focusing surface can prevent blue light source from scattering to both sides; the electrode-coated layer can prevent light leakage of the reflective focusing layer and at the same time has the welding combination capability with the substrate; the isolation layer can prevent blue light from escaping from the edge, leaving only the central part that can emit light.

[0059] Further, the conversion layer includes red light conversion substances in the form of quantum dots, and the red light conversion substances include silica gel matrix and red fluorescent powder.

[0060] As can be seen from the above description, the quantum dots in the conversion layer can absorb the light emitted by the gallium nitride and then excite red light, thereby ensuring the accuracy of light color conversion.

[0061] Further, it further includes a protective layer located at one end of the conversion layer away from the substrate.

[0062] As can be seen from the above description, the protective layer deposited on the surface of the conversion layer can wrap the conversion layer in all directions, reducing the attenuation and aging of the conversion layer.

[0063] Embodiment one

[0064] Please refer to Figure 1 and Figure 3 A red light LED manufacturing method based on GaN-based epitaxy, comprising the steps of:

[0065] S1, growing a gallium nitride epitaxial wafer 9 on an aluminum oxide substrate 10 of a chip.

[0066] Among them, the gallium nitride is the main light emitting body.

[0067] S2, etching the epitaxial wafer 9 and the epitaxial buffer layer 8 between the substrate 10 and the epitaxial wafer 9 according to a predetermined angle, to obtain a gallium nitride focusing layer 3 (thickness of 1-5um).

[0068] Specifically, a bevel 11 with a horizontal included angle of a first angle is etched on the epitaxial buffer layer, and a bevel 12 with a horizontal included angle of a second angle is etched on the epitaxial wafer, and the first angle is smaller than the second angle.

[0069] After etching, two different angle and continuous bevels are formed to obtain a gallium nitride focusing layer.

[0070] S3, according to the shape of the gallium nitride focusing layer 3, glue is applied, exposed, developed and evaporated at the end of the gallium nitride focusing layer away from the substrate, to obtain a reflective focusing layer 2 (thickness of 1-10um).

[0071] S4, at the end of the reflective focusing layer 2 away from the gallium nitride focusing layer 3, evaporate according to the preset material sequence to obtain an electrode-coated light leakage prevention layer 1 (thickness of 1-10um), and the electrode-coated light leakage prevention layer 1 is used as a contact electrode when the substrate is welded.

[0072] S5, photoetching is performed at the edge of the substrate 10 away from the gallium nitride focusing layer 3 to obtain an isolation layer 5 (thickness of 2-7um).

[0073] S6, the chip is divided, and a blackening layer 4 (thickness of 1-10um) is prepared on the side wall of the substrate 10.

[0074] Specifically, the laser focus point is divided into chips from the end of the substrate close to the isolation layer to the end of the substrate close to the epitaxial wafer by using a laser, and a blackening layer is formed on the side wall of the substrate during laser division.

[0075] S7, a red light conversion substance is coated on the outer surface of the blackening layer 4 and the end of the substrate 10 away from the epitaxial wafer 9 to form a conversion layer 6 (thickness of 2-10000um), to obtain a red light LED chip.

[0076] Specifically, red fluorescent powder is added to a silica gel matrix to obtain a red light conversion substance in the form of quantum dots;

[0077] The red light conversion substance is coated on the outer surface of the blackening layer and the end of the substrate away from the epitaxial wafer to form a conversion layer, and a protective layer 7 (thickness of 0.05-3um) is deposited on the surface of the conversion layer.

[0078] Therefore, in this embodiment, a GaN blue light chip is used as a light source, and through a plurality of optical structures and protective structures, i.e. an electrode-coated light leakage prevention layer, a reflective film focusing layer, a GaN focusing layer, a blackening layer, an isolation layer, a conversion layer and a protective layer, light is completely guided into a red light conversion substance, and blue light is converted into red light through the red light conversion substance. This integrated structure has the same physical structure and electrical characteristics as a blue light LED chip, and is convenient to use with a blue-green light LED.

[0079] Embodiment two

[0080] Please refer to Figures 1 to 3 The embodiment provides a specific manufacturing method of a red light LED based on a GaN-based epitaxial wafer:

[0081] 1.1. A gallium nitride-based epitaxial wafer is grown on an alumina substrate as the substrate, and a current spreading layer and a current injection layer are fabricated on this substrate.

[0082] 2.1 Gallium nitride focusing layer is fabricated using an ICP plasma etching machine, and the focusing layer with a certain angle is etched in two photolithography steps. The first step is to etch a bevel with a horizontal angle of 30° to 40° on the epitaxial buffer layer, and the second step is to etch a bevel with a horizontal angle of 40° to 50° on the epitaxial wafer containing the N-layer, quantum well layer and P-layer, together forming a shape with a cup-shaped focusing effect.

[0083] 3.1. Prepare a reflective focusing layer along the bowl-shaped surface of step 2.1. First, apply photoresist, expose, and develop. Then, sequentially deposit silver, nickel, titanium tungsten, nickel, and titanium tungsten metal. After removing the remaining photoresist, a high-reflectivity film layer with the same angle as designed in step 2.1 is left, which is the reflective focusing layer.

[0084] 4.1 Preparation Figure 2 The electrodes are covered with a light-leakage prevention layer, which also serves as the electrode that contacts the substrate during welding. The electrode materials are deposited in the following order: chromium (0.1-1nm), aluminum (100-500nm), titanium (10-300nm), aluminum (100-500nm), titanium (10-300nm), aluminum (100-500nm), chromium (10-200nm), titanium (10-300nm), nickel (10-900nm), and gold (10-500nm).

[0085] 5.1 Thinning and polishing are performed on the alumina substrate, leaving a thickness of 150 μm. The surface roughness Ra after polishing is 0.3 μm.

[0086] 6.1. By back-to-back positioning Figure 2 The location of the isolation layer is lithographically formed using photoresist. In the figure, the area with the isolation layer is developed without photoresist. Silver, nickel, titanium tungsten, nickel, and titanium tungsten metals are then vapor-deposited. After removing the remaining photoresist, the remaining metal structure is the optical isolation layer.

[0087] 7.1 Using a laser with a wavelength of 355nm, the laser focus is gradually processed downwards from the surface of the aluminum oxide layer. After chip dicing, a blackening layer is formed on the sidewall of the chip. The blackening layer can reduce the light emitted from the side of the chip. Light emitted from the side will reduce the light emission from the light-emitting surface and may also cause light color deviation.

[0088] 8.1 Using silica gel as a matrix and adding the compound K2SiF6:Mn4+ as a quantum dot-based light-color conversion material, according to... Figure 2 The shape is coated on the outside of the blackening layer on the sidewall of the sapphire chip and on top of the sapphire to form a conversion layer; the quantum dots in the conversion layer absorb the 445-460nm light emitted by GaN and are excited to emit red light.

[0089] 9.1, SiO2 is deposited on the surface of the conversion layer using ALD as a protective layer.

[0090] Example Three

[0091] Please refer to Figures 1 to 3 The embodiment provides another specific manufacturing method of a red light LED based on GaN epitaxy:

[0092] 1.2, GaN-based epitaxial wafer is grown on an aluminum oxide substrate as a base, and a current spreading layer and a current injection layer are made thereon.

[0093] 2.2, an ICP plasma etching machine is used to make a GaN focusing layer, and the focusing layer with a certain angle is engraved by two times of photoetching. The first time is to etch a slope with a horizontal angle of 35° on the epitaxial buffer layer, and the second time is to etch a slope with a horizontal angle of 45° on the epitaxial P, quantum well and N layer, which together form a shape with a bowl cup focusing effect.

[0094] 3.2, a reflective focusing layer is prepared along the bowl cup shape surface of step 2.2, and a distributed Bragg reflector composed of alternately deposited SiO2 and titanium oxide is prepared. The reflectivity of the reflector to the blue light emitted by GaN can reach more than 99%, and the light emitted downward is completely reflected to the light emitting surface. At the same time, the focusing effect produced by the shape also needs a high reflectivity material to reduce the light loss during reflection. According to the shape of the gallium nitride focusing layer, first, glue is coated, exposed, developed, and ICP etching is used to remove the unnecessary part of the pattern, leaving a high reflectivity film layer with the same angle as designed in step two, which is the reflective focusing layer.

[0095] 4.2, an electrode covering light leakage prevention layer is prepared in Figure 2 , which also serves as an electrode in contact with the substrate during welding. The electrode material is sequentially deposited in the order of chromium (0.1-1 nm), aluminum (100-500 nm), titanium (10-300 nm), aluminum (100-500 nm), titanium (10-300 nm), aluminum (100-500 nm), chromium (10-200 nm), titanium (10-300 nm), nickel (10-900 nm), and gold (10-500 nm).

[0096] 5.2, thinning and polishing are performed on the surface of the aluminum oxide substrate, and the thickness is retained at 120 um. After polishing, the surface roughness Ra is 0.5 um.

[0097] 6.2, a distributed Bragg reflector composed of alternately deposited SiO2 and titanium oxide is prepared, which is opposite to Figure 2The isolation layer shape is photoetched using photoresist, the photoresist is developed after the isolation layer part is photoetched, ICP etching is used to remove the part not needed in the pattern, and the remaining reflective layer material is the optical isolation layer.

[0098] 7.2, using laser with wavelength of 1064nm, gradually processing laser focus from the surface of alumina layer downwards, forming blackening layer on the sidewall of the chip after the chip is divided.

[0099] 8.2, using silica gel as the base and adding CaAlSiN3:Eu2+ fluorescent substance as the light color conversion substance, according to Figure 2 The shape is coated on the blackening layer outside the chip sapphire sidewall and above the sapphire to form the conversion layer; the fluorescent substance in the conversion layer can be positive dispersion or quantum dot dispersion, and red light is excited after absorbing 445-460nm light emitted by GaN.

[0100] 9.2, using ALD to deposit Al2O3 on the surface of the conversion layer as the protective layer.

[0101] Example Four

[0102] Please refer to Figure 2 and Figure 3 A red LED chip, comprising an alumina substrate, a gallium nitride focusing layer, a blackening layer, a conversion layer, a reflective focusing layer, an electrode-coated light leakage prevention layer, an isolation layer, and a protective layer.

[0103] The gallium nitride focusing layer is located at one end of the alumina substrate, comprising an epitaxial wafer with a first angle slope and an epitaxial buffer layer with a second angle slope, and the epitaxial buffer layer is located between the epitaxial wafer and the substrate.

[0104] The blackening layer is located on the sidewall of the substrate.

[0105] The conversion layer is located outside the blackening layer and at one end of the substrate away from the gallium nitride focusing layer.

[0106] The reflective focusing layer is located at one end of the gallium nitride focusing layer away from the substrate.

[0107] The electrode-coated light leakage prevention layer is located at one end of the reflective focusing layer away from the gallium nitride focusing layer.

[0108] The isolation layer is located at the edge of one end of the substrate away from the gallium nitride focusing layer.

[0109] The protective layer is located at one end of the conversion layer away from the substrate.

[0110] In this embodiment, the first angle is smaller than the second angle, and the epitaxial wafer with the first angle slope and the epitaxial buffer layer with the second angle slope form two different angle and continuous slopes.

[0111] The conversion layer comprises a red light conversion substance in the form of quantum dots, and the red light conversion substance comprises a silica gel base body and a red fluorescent powder.

[0112] In summary, the application provides a GaN-based epitaxial red light LED manufacturing method, which grows a gallium nitride epitaxial wafer on an aluminum oxide substrate of a chip. A sapphire substrate is used, and the substrate itself has insulation, which facilitates die bonding. The light emitting part is GaN, and the operating voltage is consistent with that of blue-green light, which facilitates circuit design when the red light LED is combined with a blue-green light LED. The epitaxial buffer layer is etched at a first angle, and the epitaxial wafer is etched at a second angle to obtain a gallium nitride focusing layer. A blackening layer is prepared on the sidewall of the substrate, which can concentrate the light emitted by the quantum well to the light emitting surface and reduce the proportion of light emitted to the sidewall blackening layer. The isolation layer is a lightproof material, which can constrain the blue light emitted by GaN to the front surface and reduce the side leakage of blue light. The conversion layer is a light color conversion working layer, which converts the front blue light to red light through quantum dots. With the assistance of the isolation layer, the conversion of red light is more complete, and the leakage of blue light is less. The protective layer can effectively isolate air and water vapor, prevent oxidation and attenuation of quantum dots, and maintain the light conversion efficiency for a long time. Therefore, the red light LED chip and the manufacturing method thereof improve the overall performance of the red light LED and facilitate the combination of the red light LED with the blue-green light LED.

[0113] The above description is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent transformation or direct or indirect application in the related technical field based on the content of the specification and drawings is also included in the patent protection scope of the application.

Claims

1. A method for manufacturing red LEDs based on GaN-based epitaxy, characterized in that, Including the following steps: Gallium nitride epitaxial wafers are grown on the alumina substrate of the chip; The epitaxial wafer and the epitaxial buffer layer located between the substrate and the epitaxial wafer are etched at a preset angle to obtain a gallium nitride focusing layer; Based on the shape of the gallium nitride focusing layer, a reflective focusing layer is prepared at the end of the gallium nitride focusing layer away from the substrate, specifically a distributed Bragg mirror composed of alternating silicon dioxide and titanium oxide by vapor deposition; The chip is diced, and a blackening layer is prepared on the sidewall of the substrate; A red light conversion material is coated on the outside of the blackening layer and on the end of the substrate away from the epitaxial wafer to form a conversion layer, thereby obtaining a red LED chip. After depositing a reflective focusing layer composed of alternating silicon dioxide and titanium oxide at the end of the gallium nitride focusing layer away from the substrate, the following is included: At the end of the reflective focusing layer away from the gallium nitride focusing layer, an electrode coating light leakage prevention layer is deposited according to a preset material sequence to obtain an electrode coating light leakage prevention layer, and the electrode coating light leakage prevention layer is used as a contact electrode when soldering with the substrate. The process of vapor deposition according to a preset material sequence includes: The following layers are deposited sequentially: chromium with a thickness of 0.1-1 nm, aluminum with a thickness of 100-500 nm, titanium with a thickness of 10-300 nm, aluminum with a thickness of 100-500 nm, titanium with a thickness of 10-300 nm, aluminum with a thickness of 100-500 nm, chromium with a thickness of 10-200 nm, titanium with a thickness of 10-300 nm, nickel with a thickness of 10-900 nm, and gold with a thickness of 10-500 nm.

2. The method for manufacturing a red LED based on GaN-based epitaxy according to claim 1, characterized in that, The step of etching the epitaxial wafer and the epitaxial buffer layer located between the substrate and the epitaxial wafer at a preset angle to obtain the gallium nitride focusing layer includes: A bevel with a horizontal angle of a first angle is etched on the epitaxial buffer layer, and a bevel with a horizontal angle of a second angle is etched on the epitaxial wafer, wherein the first angle is smaller than the second angle; After etching, two continuous inclined planes with different angles are formed, resulting in a gallium nitride focused layer.

3. The method for manufacturing a red LED based on GaN-based epitaxy according to claim 1, characterized in that, After obtaining the electrode coating anti-leakage layer, the following is included: Photolithography is performed on the edge of the substrate at the end furthest from the gallium nitride focusing layer to obtain an isolation layer.

4. The method for manufacturing a red LED based on GaN-based epitaxy according to claim 1, characterized in that, The process before depositing the reflective focusing layer includes: thinning and polishing the alumina substrate.

5. The method for manufacturing a red LED based on GaN-based epitaxy according to claim 3, characterized in that, Dividing the chip and preparing a blackening layer on the sidewall of the substrate includes: A laser is used to divide the chip from the end of the substrate near the isolation layer to the end of the substrate near the epitaxial wafer, and a blackening layer is formed on the sidewall of the substrate during laser dicing.

6. The method for manufacturing a red LED based on GaN-based epitaxy according to claim 1, characterized in that, The step of coating the red light conversion material outside the blackening layer and at the end of the substrate away from the epitaxial wafer to form a conversion layer includes: Red phosphor was added to a silicone matrix to obtain a red light conversion material in the form of quantum dots; The red light conversion material is coated on the outer surface of the blackening layer and the end of the substrate away from the epitaxial wafer to form a conversion layer, and a protective layer is deposited on the surface of the conversion layer.

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