A preparation method for GaN-based vertical structure micro-cavity Micro-LED

Abstract

The invention discloses a GaN-based vertical micro-cavity Micro-LED based on electroplating technology and a preparation method thereof. The micro-cavity Micro-LED of the invention has a narrow half-height width of light emission and good light emission directionality. By thinning the chip thickness and using the metal reflector of the p-GaN layer (5) and the dielectric film reflector of the n-GaN layer as the end face of the resonant cavity, a vertical resonant micro-cavity structure is formed, which will suppress the light emission from the side wall and improve the directionality of the front light emission, thereby reducing the crosstalk effect between adjacent pixels of the Micro-LED display. At the same time, the resonant micro-cavity structure will select a specific wavelength to narrow its light emission spectrum and increase the spectral purity, which will be beneficial to improving the threshold of the Micro-LED display. The vertical structure Micro-LED of the invention has a large active area and less light absorption by n-GaN; the current expansion is good, the voltage is low, the current density is small, and it has advantages in light efficiency, saturation current, and long-term reliability; secondly, the Cu substrate has good electrical conductivity and thermal conductivity, and the chip thermal resistance is small.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a GaN-based vertical structure micro-cavity Micro-LED. Background Art

[0002] Micro-LED has important applications in display and visible light communication. The display industry is a leading industry in the information age, with an annual output value of more than 100 billion US dollars. Light-emitting diodes (LEDs) have gradually become the mainstream in the field of display lighting with irreplaceable advantages such as energy saving, high efficiency, durability, and mercury-free. Micro-LED is considered to be the most promising display technology after TFT-LCD and AMOLED technology due to its excellent characteristics such as ultra-high resolution, high brightness, ultra-power saving and fast response speed. In Micro-LED display, the size of the pixel unit is reduced to improve the display accuracy and resolution. LED is similar to Lambertian light source, and its light emission angle is large. The chip thickness obtained by Trace-Pro software simulation is 10μm, and when the size is 50μm, the side wall light emission ratio reaches 15%. It can be seen that as the size of the Micro-LED pixel unit decreases, its side wall area ratio will also increase with the size reduction, resulting in an increase in the side wall light emission that cannot be ignored, causing the "cross talk" effect of adjacent pixel units to become significant, greatly reducing the performance of Micro-LED display, such as contrast and clarity. At present, the research on Micro-LED display focuses more on key process technologies such as mass transfer, but lacks research on the above-mentioned "cross talk" problem. Professor Guo Haozhong of National Chiao Tung University in Taiwan, China, and others use photolithography and other processes to make a "dam" around each Micro-LED pixel to absorb the sidewalls and part of the oblique outgoing light to reduce the "cross talk" effect of adjacent pixels. However, this method increases the process steps, and the dam itself is part of the pixel, which limits the further reduction of the overall pixel size. In addition, the half-height width of the conventional Micro-LED is relatively wide, reaching 20nm, which limits the performance of the Micro-LED display threshold.

[0003] In addition, visible light communication based on Micro-LED has the characteristics of available visible light resources, wide available visible light bandwidth, strong security (no signal if blocked), etc., and has many application prospects in the intelligent interconnected society. However, due to the piezoelectric polarization effect of MQW (quantum well) of GaN-based Micro-LED, the luminescence rate is very slow, which greatly limits the bandwidth of Micro-LED as a visible light communication light source. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a GaN-based vertical structure microcavity Micro-LED, which can improve the front light emission directionality, light emission speed and light extraction efficiency of the Micro-LED, reduce the volume of the Micro-LED and improve the integration.

[0005] The GaN-based vertical structure microcavity Micro-LED of the present invention comprises a Micro-LED chip and a substrate seven, wherein the Micro-LED chip is located on the substrate seven; the Micro-LED chip comprises a dielectric film, an n-GaN layer, an MQW layer, a p-GaN layer and a reflector electrode from top to bottom, wherein the reflector electrode is connected to the substrate seven; the widths of the n-GaN layer, the MQW layer and the p-GaN layer are equal, and the width of the reflector electrode is equal to the width of the substrate seven; the width of the dielectric film is smaller than that of the n-GaN layer, and a mesa is exposed on both sides of the n-GaN layer; the width of the reflector electrode is larger than that of the n-GaN layer, the MQW layer and the p-GaN layer, and a mesa is exposed on both sides of the reflector electrode, and a stacked structure formed by the n-GaN layer, the MQW layer and the p-GaN layer exposes two side walls; a passivation layer is provided on the mesa and the side wall; an ohmic contact metal layer is provided on the passivation layer on one side, and a portion of the top of the ohmic contact metal is in contact with the exposed mesa of the n-GaN layer.

[0006] The size of the Micro-LED chip is 10~1000μm; the reflector electrode is Ni / Ag / Pt / Au, which is also a metal electrode.

[0007] The method for preparing the GaN-based vertical structure micro-cavity Micro-LED of the present invention comprises the following steps:

[0008] (1) Growing a u-GaN layer, an n-GaN layer, an MQW layer and a p-GaN layer in sequence on substrate 1 to obtain an LED epitaxial material;

[0009] (2) preparing a reflector electrode on the surface of the p-GaN layer in step (1);

[0010] (3) preparing substrate 7 on the reflector electrode surface obtained in step (2);

[0011] (4) removing substrate 1 of the structure obtained in step (3);

[0012] (5) removing the u-GaN layer and part of the n-GaN layer of the structure obtained in step (4) by dry etching to the designed cavity length;

[0013] (6) etching the structure obtained in step (5) to the reflector electrode to form a chip table;

[0014] (7) a passivation layer is formed on the upper surface of the chip table 2 obtained in step (6), the n-GaN layer, the MQW layer, and the side wall of the p-GaN layer, and a passivation layer is also formed on both sides of the upper surface of the n-GaN layer except for the dielectric film position, and the shape of the prepared passivation layer is a right-angled Z-shape;

[0015] (8) preparing an ohmic contact metal on the passivation layer on one side of the structure obtained in step (7), wherein a portion of the upper portion of the ohmic contact metal is in contact with the upper surface of the n-GaN layer;

[0016] (9) A dielectric film is deposited on the surface of the n-GaN layer of the vertical structure Micro-LED chip obtained in step (8), and a GaN-based vertical structure Micro-LED chip is obtained after cutting.

[0017] In the step (1), the substrate 1 is one of gemstone, silicon, silicon carbide, and gallium nitride; the thickness of the u-GaN layer is 4-6 μm, the thickness of the n-GaN layer is 4-6 μm, the thickness of the MQW layer is 50-500 nm, and the thickness of the p-GaN layer is 50-200 nm; the MQW layer is composed of an alternating cycle of InGaN layer and GaN layer, wherein the thickness of the InGaN layer is 2 nm, and the thickness of the GaN layer is 10 nm; the preparation method of the u-GaN layer, the n-GaN layer, the MQW layer, and the p-GaN layer is MOCVD growth.

[0018] In the step (2), the preparation method of the reflector electrode is electron beam evaporation, and the deposition temperature is 110-130°C; the reflector electrode is Ni / Ag / Pt / Au, wherein the thickness of Ni is 0.5, the thickness of Ag is 200, the thickness of Pt is 50, and the thickness of Au is 200nm.

[0019] In the step (3), the preparation method of the substrate seven is electroplating; the material of the substrate seven is one of Cu and Ni, and the thickness of the substrate seven is 70-100 μm.

[0020] In the step (4), the substrate 1 is removed by one of laser stripping, grinding and polishing, and wet etching.

[0021] In the step (5), the thickness of the n-GaN layer after etching is 50-500 nm, and the designed cavity length means that the cavity length is an integer multiple of the wavelength.

[0022] In the step (6), after etching, the width of the reflective mirror layer is greater than that of the u-GaN layer, the n-GaN layer, the MQW layer and the p-GaN layer. The u-GaN layer, the n-GaN layer, the MQW layer and the p-GaN layer are located in the middle of the reflective mirror layer, and the exposed portions on both sides are chip mesas.

[0023] In the step (7), the passivation layer is one of SiO2 and Ta2O5, the passivation layer is prepared by chemical deposition, and the thickness of the passivation layer is 200-250 nm.

[0024] In the step (8), the ohmic contact metal is Cr / Al / Ti / Au; the preparation method is electron beam evaporation; and the deposition temperature is 15-25°C.

[0025] In the step (9), the dielectric film is one or more of SiO2, Si3N4, TiO2, and is prepared by PECVD deposition. The thickness of the dielectric film is 251-264 nm.

[0026] 1. The half-height width of the light emission is narrow and the light emission directionality is good. By reducing the chip thickness and using the metal reflector of the p-GaN layer (5) and the dielectric film reflector of the n-GaN layer as the end face of the resonant cavity, a vertical resonant microcavity structure is formed, which will suppress the side wall light emission and improve the front light emission directionality, thereby reducing the crosstalk effect between adjacent pixels of the Micro-LED display. At the same time, the resonant microcavity structure will select a specific wavelength to narrow its light emission spectrum and increase the spectral purity, which will help to increase the threshold of the Micro-LED display;

[0027] Second, fast light emission speed. Due to the Purcell effect, the vertical resonant microcavity formed while reducing the size of the Micro-LED will increase its light emission speed, thereby increasing the bandwidth of the Micro-LED light source in visible light communication;

[0028] 3. High brightness and high efficiency. There is a large difference in refractive index between GaN material and air, and total reflection occurs at the interface, so that most of the emitted light of the LED device is confined inside the device. At the same time, the thick film effect of the epitaxial nitride will cause many waveguide modes to exist inside the device, so that the emitted light is coupled into the waveguide mode, transmitted inside the device, and finally absorbed and lost. Due to the microcavity effect, the spontaneous emission rate at the resonant wavelength increases. At the same time, most of the light emission angles are concentrated in the light extraction window, and only a very small amount of light is absorbed by the active layer, making its luminous brightness higher. Micro-LEDs with reduced thickness will suppress the waveguide modes in conventional thick-film Micro-LEDs, which will improve their light extraction efficiency, the brightness of Micro-LED displays, and the signal stability of visible light communications;

[0029] 4. Higher integration and better temperature stability. The thickness of the chip is mostly in the order of the central wavelength of the light emission, which will greatly improve the integration of Micro-LED display. The emission spectrum of traditional LED quantum wells becomes wider with the increase of temperature and the peak wavelength is red-shifted. However, due to the presence of upper and lower reflectors, the wavelength shift of the vertical structure Micro-LED depends on the temperature coefficient of the optical cavity, and the temperature stability is good.

[0030] 5. The photoelectric and thermal performance is better. The vertical structure LED has a large active area, and n-GaN absorbs less light; the current expansion is better, the voltage is lower, and the current density is smaller, which has advantages in light efficiency, saturation current, and long-term reliability; secondly, the Cu substrate has good electrical and thermal conductivity, and the chip thermal resistance is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure corresponding to step (1) in the preparation method provided by the present invention;

[0032] Figure 2 A schematic diagram of the structure corresponding to step (2) in the preparation method provided by the present invention;

[0033] Figure 3 A schematic structural diagram corresponding to step (3) in the preparation method provided by the present invention;

[0034] Figure 4 A schematic structural diagram corresponding to step (4) in the preparation method provided by the present invention;

[0035] Figure 5 A schematic structural diagram corresponding to step (5) in the preparation method provided by the present invention;

[0036] Figure 6 A schematic structural diagram corresponding to step (6) in the preparation method provided by the present invention;

[0037] Figure 7 This is a schematic structural diagram corresponding to step (7) in the preparation method provided by the present invention;

[0038] Figure 8 A schematic structural diagram corresponding to step (8) in the preparation method provided by the present invention;

[0039] Fig. 9 This is a schematic diagram of the structure of the vertical microcavity GaN-based Micro-LED provided by the present invention.

[0040] Description of reference numerals:

[0041] 1. Substrate one; 2. u-GaN layer; 3. n-GaN layer; 4. MQW (quantum well) layer; 5. p-GaN layer; 6. Reflector electrode; 7. Substrate seven; 8. Passivation layer; 9. Ohmic contact metal; 10. Dielectric film; 11. Chip table. DETAILED DESCRIPTION

[0042] In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, they are described in detail below in conjunction with specific embodiments. Example

[0043] The structure of the vertical microcavity GaN-based Micro-LED of the present invention is as follows Fig. 9 As shown, it includes a Micro-LED chip and a substrate 7, wherein the Micro-LED chip is located on the substrate 7; the Micro-LED chip includes a dielectric film 10, an n-GaN layer 3, an MQW layer 4, a p-GaN layer 5 and a reflector electrode 6 from top to bottom, wherein the reflector electrode 6 is connected to the substrate 7 7; the widths of the n-GaN layer 3, the MQW layer 4 and the p-GaN layer 5 are equal, and the width of the reflector electrode 6 is equal to the width of the substrate 7 7; the width of the dielectric film 10 is smaller than that of the n-GaN layer 3, and the width of the n-GaN layer 3 is equal to that of the p-GaN layer 5. -Mesas 11 will be exposed on both sides of the GaN layer; the width of the reflector electrode is larger than that of the n-GaN layer 3, the MQW layer 4, and the p-GaN layer 5, and mesas 11 will be exposed on both sides of the reflector electrode 6, and two side walls will be exposed in the n-GaN layer 3, the MQW layer 4, and the p-GaN layer 5; there is a passivation layer 8 on the mesas 11 and the side walls; the shape of the passivation layer 8 is a right-angled Z-shape; an ohmic contact metal layer 9 is provided on one side of the passivation layer 8, and a portion of the top of the ohmic contact metal 9 will be in contact with the exposed mesa 11 on the n-GaN layer 3.

[0044] In the present invention, the reflector electrode is Ni / Ag / Pt / Au, which is also a metal electrode. Example

[0045] The method for preparing a vertical microcavity GaN-based Micro-LED provided in this embodiment includes the following steps:

[0046] (1) u-GaN layer 2 (thickness 5μm), n-GaN layer 3 (thickness 5μm), [InGaN(2nm) / GaN(10nm)]8MQW (quantum well) layer 4 (thickness 96nm), and p-GaN layer 5 (thickness 100nm) are grown in sequence on (0001) plane sapphire (substrate 1) by MOCVD to obtain LED epitaxial material, the emission wavelength of which is determined by the In component in the MQW (quantum well) layer 4. In this embodiment, the emission wavelength is 460nm. The structure of the LED epitaxial material obtained in step (1) is as follows: Figure 1 shown.

[0047] (2) Using electron beam evaporation method to make the reflector electrode 6 on the p-GaN layer 5, the deposition temperature is 120°C; the reflector electrode is Ni / Ag / Pt / Au, where the thickness of Ni is 0.5, the thickness of Ag is 200, the thickness of Pt is 50, and the thickness of Au is 200nm. The structure obtained after this step is as follows Figure 2 shown.

[0048] (3) A substrate 7 is prepared on the reflector electrode 6 obtained in step (2) by electroplating. Specifically, a layer of Cu is electroplated using a copper plating solution, and the thickness of the Cu layer 7 is 100 μm. The structure obtained after this step is as follows: Figure 3 shown.

[0049] (4) Remove the sapphire (substrate 1) of the structure obtained in step (3) by 248nm KrF laser lift-off. The structure obtained after this step is as follows Figure 4 shown.

[0050] (5) Use dry etching (ICP) to completely etch the u-GaN layer 2 and partially etch the n-GaN layer 3 to the designed cavity length (375nm). The etching conditions are: ICP power 500W, RF power 150W, Cl2 / BCl3 40sccm and 5sccm respectively, etching time 680s, and a total etching depth of 9.8μm. The structure obtained after this step is as follows Figure 5 shown.

[0051] (6) Use dry etching (ICP) to etch out the chip mesa 11 to the reflector electrode layer 6. The etching conditions are: ICP power 500W, RF power 50W, C l2 / BCl3 was 40sccm and 5sccm respectively, 4μm thick AZ4620 photoresist was spin-coated, the etching time was 100s, and the etching depth was about 400nm. The structure obtained after this step is as follows Figure 6 shown.

[0052] (7) Using PECVD, a SiO2 passivation layer 8 is deposited on the n-GaN layer 3, the mesa 11 and the sidewall of the chip, wherein the thickness of the SiO2 is about 225 nm. The structure obtained after this step is as follows: Figure 7 As shown, it can be seen that the shape of the passivation layer 8 is a right-angled Z-shape.

[0053] (8) Using electron beam evaporation method, ohmic contact metal 9 is prepared on the n-GaN layer 3 and the passivation layer 8 on one side of the structure obtained in step (7). The deposition temperature is 20°C, and the ohmic contact metal is Cr / Al / Ti / Au. The structure obtained after this step is as follows Figure 8 As shown,

[0054] (9) Three layers of SiO2 / TiO2 dielectric film layers 10 are deposited on the surface of the n-GaN layer 3 of the structure obtained in step (8), wherein the thickness of SiO2 is 78nm, the thickness of TiO2 is 51nm, and the reflectivity of the dielectric film is about 89%. After cutting, a vertical microcavity GaN-based Micro-LED is obtained, as shown in FIG. Fig. 9 shown.

[0055] The final sizes of the vertical microcavity GaN-based Micro-LEDs are 30, 50, 80, and 100 μm. Example

[0056] The method for preparing a vertical microcavity GaN-based Micro-LED provided in this embodiment includes the following steps:

[0057] (1) First, u-GaN layer 2 (thickness 5μm), n-GaN layer 3 (thickness 5μm), [InGaN (2nm) / GaN (10nm)] 8MQW (quantum well) layer 4 (thickness 96nm), and p-GaN layer 5 (thickness 100nm) are grown in sequence on the (111) plane Si (substrate 1) by MOCVD to obtain LED epitaxial material. The structure of the LED epitaxial material obtained in step (1) is as follows Figure 1 shown.

[0058] (2) Using electron beam evaporation method to make the reflector electrode 6 on the p-GaN layer 5, the deposition temperature is 120 degrees; the reflector electrode is Ni / Ag / Pt / Au, where the thickness of Ni is 0.5, the thickness of Ag is 200, the thickness of Pt is 50, and the thickness of Au is 200nm. The structure obtained after this step is as follows Figure 2 shown.

[0059] (3) A substrate 7 is prepared on the reflector electrode 6 obtained in step (2) by electroplating. Specifically, a copper plating solution is used to electroplate a layer of Cu, wherein the thickness of the Cu layer is 100 μm; and then a nickel plating solution is used to electroplate a layer of Ni, wherein the thickness of the Ni layer is 7 to 10 μm. The structure obtained after this step is as follows: Figure 3 shown.

[0060] (4) Use HF acid etching to remove the Si (substrate 1) of the structure obtained in step (4). The structure obtained after this step is as follows Figure 4 shown.

[0061] (5) Use dry etching (ICP) to completely etch the u-GaN layer 2 and partially etch the n-GaN layer 3 to 375nm. The etching conditions are: ICP power 500W, RF power 150W, Cl2 / BCl3 40sccm and 5sccm respectively, etching time 650s, and a total etching depth of 9.3μm. The structure obtained after this step is as follows Figure 5 shown.

[0062] (6) Use dry etching (ICP) to etch the chip table to the reflector electrode layer 6. The etching conditions are: ICP power 500W, RF power 50W, C l2 / BCl3 was 40sccm and 5sccm respectively, 4μm thick AZ4620 photoresist was spin-coated, the etching time was 150s, and the etching depth was about 600nm. The structure obtained after this step is as follows Figure 6 shown.

[0063] (7) Using PECVD, a SiO2 passivation layer 8 is deposited on the n-GaN layer 3 and the chip sidewalls, wherein the SiO2 thickness is about 225 nm. The structure obtained after this step is as follows: Figure 7 As shown, it can be seen that the shape of the passivation layer 8 is a right-angled Z-shape.

[0064] (8) Using electron beam evaporation method, ohmic contact metal 9 is prepared on the n-GaN layer 3 and passivation layer 8 of the structure obtained in step (7). The deposition temperature is 20°C, and the ohmic contact metal is Cr / Al / Ti / Au. The structure obtained after this step is as follows Figure 8 shown.

[0065] (9) Four layers of SiO2 / Si3N4 dielectric film layers 10 are deposited on the surface of the n-GaN layer 3 of the structure obtained in step (8), wherein the thickness of SiO2 is 78nm, the thickness of Si3N4 is 56nm, and the reflectivity of the dielectric film is about 85%. After cutting, a vertical microcavity GaN-based Micro-LED is obtained, and its structure is as follows: Fig. 9 shown.

[0066] The final sizes of the vertical microcavity GaN-based Micro-LEDs are 30, 50, 80, and 100 μm.

[0067] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a GaN-based vertical structure micro-cavity Micro-LED, characterized in that: A GaN-based vertical micro-cavity Micro-LED based on electroplating technology is provided, wherein the Micro-LED chip and a substrate seven are provided, wherein the Micro-LED chip is provided on the substrate seven; the Micro-LED chip comprises a dielectric film, an n-GaN layer, an MQW layer, a p-GaN layer and a reflector electrode from top to bottom, wherein the reflector electrode is connected to the substrate seven; the widths of the n-GaN layer, the MQW layer and the p-GaN layer are equal, and the width of the reflector electrode is equal to the width of the substrate seven; the width of the dielectric film is smaller than that of the n-GaN layer, and a mesa is exposed on both sides of the n-GaN layer; the width of the reflector electrode is larger than that of the n-GaN layer, the MQW layer and the p-GaN layer, and a mesa is exposed on both sides of the reflector electrode, and a stacked structure formed by the n-GaN layer, the MQW layer and the p-GaN layer exposes two side walls; a passivation layer is provided on the mesa and the side wall; an ohmic contact metal layer is provided on the passivation layer on one side, and a portion of the top of the ohmic contact metal is in contact with the exposed mesa of the n-GaN layer; The thickness of the n-GaN layer is 50-500nm, the thickness of the MQW layer is 50-500nm, and the thickness of the p-GaN layer is 50-200nm; the MQW layer is composed of an alternating cycle of an InGaN layer and a GaN layer, wherein the thickness of the InGaN layer is 2nm, and the thickness of the GaN layer is 10nm; The reflector electrode is Ni / Ag / Pt / Au, which is also a metal electrode; The material of the substrate 7 is one of Cu and Ni; the passivation layer is one of SiO2 and Ta2O5, the thickness of the passivation layer is 200-250nm, and the shape of the passivation layer is a right-angled Z-shape; The dielectric film is one or more of SiO2, Si3N4, and TiO2, and the thickness of the dielectric film is 251-264 nm; The preparation method comprises the following steps: (1) Growing a u-GaN layer, an n-GaN layer, an MQW layer and a p-GaN layer in sequence on substrate 1 to obtain an LED epitaxial material; (2) preparing a reflector electrode on the surface of the p-GaN layer in step (1); (3) preparing substrate 7 on the reflector electrode surface obtained in step (2); (4) removing substrate 1 of the structure obtained in step (3); (5) removing the u-GaN layer and part of the n-GaN layer of the structure obtained in step (4) by dry etching to the designed cavity length; (6) etching the structure obtained in step (5) to the reflector electrode to form a chip table; (7) preparing a passivation layer on the upper surface of the chip table obtained in step (6), as well as on the side walls of the n-GaN layer, the MQW layer, and the p-GaN layer. A passivation layer is also prepared on both sides of the upper surface of the n-GaN layer except for the position of the dielectric film. The shape of the prepared passivation layer is a right-angled Z-shape; (8) preparing an ohmic contact metal on the passivation layer on one side of the structure obtained in step (7), wherein a portion of the upper portion of the ohmic contact metal is in contact with the upper surface of the n-GaN layer; (9) A dielectric film is deposited on the surface of the n-GaN layer of the vertical structure Micro-LED chip obtained in step (8), and a GaN-based vertical structure Micro-LED chip is obtained after cutting.

2. The method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, characterized in that: The size of the Micro-LED chip is 10~1000μm.

3. The method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, characterized in that: In the step (1), the substrate 1 is one of sapphire, silicon, silicon carbide, and gallium nitride, and the thickness of the u-GaN layer is 4-6 μm; the preparation method of the u-GaN layer, the n-GaN layer, the MQW layer, and the p-GaN layer is MOCVD growth.

4. The method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, characterized in that: In the step (2), the preparation method of the reflector electrode is electron beam evaporation, and the deposition temperature is 110-130°C; the reflector electrode is Ni / Ag / Pt / Au, wherein the thickness of Ni is 0.5nm, the thickness of Ag is 200nm, the thickness of Pt is 50nm, and the thickness of Au is 200nm.

5. The method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, characterized in that: In the steps (3) and (4), the preparation method of substrate seven is electroplating; the thickness of substrate seven is 70-100 μm; and the removal method of substrate one is one of laser stripping, grinding and polishing, and wet etching.

6. The method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, wherein in step (5), the designed cavity length of the n-GaN layer after etching means that the cavity length is an integer multiple of the wavelength.

7. According to the method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, in the step (6), after etching, the width of the reflector electrode is greater than that of the u-GaN layer, the n-GaN layer, the MQW layer and the p-GaN layer, and the u-GaN layer, the n-GaN layer, the MQW layer and the p-GaN layer are located in the middle position on the reflector electrode, and the exposed parts on both sides are chip table tops.

8. According to the method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, in the steps (7) and (8), the preparation method of the passivation layer is chemical deposition; the ohmic contact metal is Cr / Al / Ti / Au; the preparation method is electron beam evaporation; and the deposition temperature is 15~25°C.

9. The method for preparing a GaN-based vertical structure micro-cavity Micro-LED according to claim 1, wherein in step (9), the dielectric film is prepared by PECVD deposition.

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