Micro-LED device structure with high resolution and high refresh rate and preparation method thereof

Abstract

The invention discloses a high-resolution high-refresh-rate Micro-LED device structure and a preparation method thereof. A GaN-based full-color pixel chip is arranged at the upper end of a multi-layer glass carrier plate, and a driving IC chip is arranged at the lower end of the glass carrier plate; the GaN-based full-color pixel chip comprises a red light layer, a blue light layer and a green light layer which are vertically stacked in a step shape from bottom to top, and the light-emitting area is sequentially reduced from bottom to top; the driving IC chip is connected with the GaN-based full-color pixel chip through a multi-layer glass carrier plate and controls all light-emitting layers in the GaN-based full-color pixel chip respectively, and high-resolution and high-refresh-rate color display is achieved. According to the GaN-based full-color pixel chip in the scheme, the red light layer, the green light layer and the blue light layer which are different in light emitting size are stacked in a vertical step shape and are connected with the driving IC chip through the metal expansion electrode and the multi-layer glass carrier plate, and high-refresh-rate circuit driving is carried out; therefore, the pixel chips at the same position can emit light of different colors in different time domains, the resolution is improved to three times of that of an existing three-color sub-pixel transverse arrangement technical scheme while color display is achieved, high-yield, low-cost, high-resolution and high-refresh-rate Micro-LED device structure preparation can be achieved, Micro-LED industrialization can be supported to be rapidly promoted, and the method is suitable for large-scale popularization and application. And the strategic requirement of a new generation of national information technology industry on novel display is met.

Description

Technical Field

[0001] The present invention belongs to the field of Micro-LED, and specifically relates to a high-resolution and high-refresh rate Micro-LED device structure and a preparation method thereof. Background Art

[0002] Micro-LED is a current research hotspot for solid-state display devices. Compared with traditional LCD and OLED displays, Micro-LED has the advantages of ultra-high brightness, high reliability, high contrast, low power consumption, and thinness. It is the preferred technical solution for avionics system display terminals in all fields of land, sea and air. Civilian products such as stereoscopic display, e-sports large screen, commercial super-large size, and space-shaped screens are in urgent need of engineering-based Micro-LED display technology. Accordingly, the technology is also constantly developing towards high-resolution, high-refresh rate, and high-freedom spatial shape panoramic immersive display trends.

[0003] The Chinese patent application number 201210015781.2 discloses a white light LED epitaxial wafer and its manufacturing process and a method for manufacturing a white light LED chip. The white light LED epitaxial wafer is formed with a GaN buffer layer on a sapphire substrate, and a green light N-GaN contact layer, a green light InGaN / GaN multi-quantum well light-emitting layer, a green light P-GaN contact layer, a blue-green light cascade layer, a blue light N-GaN contact layer, a blue light InGaN / GaN multi-quantum well light-emitting layer, and a blue light P-GaN contact layer are sequentially formed on the buffer layer. , red-blue light cascade layer, red light N-GaP current expansion and ohmic contact layer, red light N-AlGaInP transition and lower limiting layer, red light multiple quantum well AlGaInP luminescent layer, red light P-AlGaInP upper limiting layer, red light P-GaP current expansion layer, yellow-red light cascade layer, yellow light N-GaP current expansion and ohmic contact layer, yellow light N-AlGaInP transition and lower limiting layer, yellow light multiple quantum well AlGaInP luminescent layer, yellow light P-AlGaInP upper limiting layer and yellow light P-GaP current expansion layer.

[0004] A Chinese patent with application number 201810011670.1 discloses a MicroLED color display array structure, including a transparent substrate, a red sub-pixel, a green sub-pixel, a blue sub-pixel, a cathode structure, an anode structure and a driving circuit substrate. The red sub-pixel, the green sub-pixel and the blue sub-pixel are all provided with an electrode addressing module.

[0005] A Chinese patent with application number 201910677032.8 discloses a white light Micro LED structure based on a flip-chip structure, including a circuit substrate and a Micro LED chip. The Micro LED chips are evenly spaced and staggered on the circuit substrate. The Micro LED chip is connected to the positive and negative electrodes of the circuit substrate through a P electrode and an N electrode. The P electrode is connected to the N-type GaN through a P-type GaN. A quantum well is formed at the interface between the P-type GaN and the N-type GaN. Quantum dot material is poured into the Micro LED chip, and black glue is filled in the gaps between the Micro LED chips.

[0006] The above-mentioned patents have studied the Micro-LED white light epitaxy or full-color integration solutions, or only involved the lighting field, or did not involve high-resolution and high-refresh rate display related technical points from the device structure and its driving method. At present, Micro-LED display technology is mainly equipped with TFT and CMOS active drive substrates. The low pixel yield and high cost of the device in the process have always been important issues restricting the Micro-LED technology from entering the industrialization stage. This problem is particularly prominent on large-size display screens. The industry has gradually begun to turn to the study of splicing large screen solutions. Then how to explore a Micro-LED device structure suitable for high-resolution and high-refresh rate driving and effectively realize the partition control of the splicing unit is the current research hotspot, which is conducive to supporting the rapid advancement of Micro-LED industrialization and meets the strategic needs of the country's new generation of information technology industry for new displays. Summary of the invention

[0007] In view of the engineering technical problems of low process yield and high cost of Micro-LED high-resolution devices in the above-mentioned prior art, the purpose of the present invention is to provide a high-resolution and high-refresh rate Micro-LED device structure and a preparation method thereof.

[0008] The specific technical solution for achieving the purpose of the present invention is:

[0009] A high-resolution and high-refresh rate Micro-LED device structure, including a GaN-based full-color pixel chip, a multi-layer glass substrate, and a driver IC chip;

[0010] The GaN-based full-color pixel chip is arranged on the upper end of the multi-layer glass carrier, and the driver IC chip is arranged on the lower end of the glass carrier;

[0011] The GaN-based full-color pixel chip includes a red light layer, a blue light layer and a green light layer, wherein the red light layer, the blue light layer and the green light layer are stacked vertically in a stepped manner from bottom to top, and the light-emitting area decreases sequentially from bottom to top;

[0012] The driver IC chip is connected to the GaN-based full-color pixel chip through a multi-layer glass carrier, and controls each light-emitting layer in the GaN-based full-color pixel chip respectively, so as to achieve high-resolution and high-refresh-rate color display.

[0013] Furthermore, the GaN-based full-color pixel chip is obtained by a GaN-based full-color pixel film through a miniaturization process, and the GaN-based full-color pixel film is obtained based on GaN-based red, green and blue light vertical stacking epitaxy, or is obtained by bonding red, green and blue monochrome GaN-based epitaxial films to a carrier respectively.

[0014] Furthermore, when the GaN-based full-color pixel film is obtained based on GaN-based red, green and blue light vertical stacking epitaxy:

[0015] The GaN-based full-color pixel chip includes, from bottom to top, based on a multi-layer glass carrier, a first ohmic contact electrode, a red P-type GaN, an InGaN red light emitting layer, a red N-type GaN, a red and blue non-doped buffer layer, a blue P-type GaN, an InGaN blue light emitting layer, a blue N-type GaN, a blue-green non-doped buffer layer, a green P-type GaN, an InGaN green light emitting layer, a green N-type GaN and a second ohmic contact electrode.

[0016] Furthermore, when the GaN-based full-color pixel film is obtained by bonding red, green, and blue single-color GaN-based epitaxial films to a carrier respectively:

[0017] The GaN-based full-color pixel chip includes, from bottom to top, based on a multi-layer glass carrier: a first ohmic contact electrode, a red light P-type GaN, an InGaN red light emitting layer, a red light N-type GaN, a second ohmic contact electrode, a red and blue dielectric layer, a third ohmic contact electrode, a blue light P-type GaN, an InGaN blue light emitting layer, a blue light N-type GaN, a fourth ohmic contact electrode, a blue-green dielectric layer, a fifth ohmic contact electrode, a green light P-type GaN, an InGaN green light emitting layer, a green light N-type GaN, and a sixth ohmic contact electrode.

[0018] Furthermore, the light emitting area ratio of the red light layer, the blue light layer and the green light layer is 6.5:1.5:1.

[0019] Furthermore, each layer of the sidewall of the GaN-based full-color pixel chip is provided with a metal extension electrode connected to the multi-layer glass carrier;

[0020] A SiO2 dielectric layer is arranged between the metal extension electrodes arranged on the side walls of each layer.

[0021] Furthermore, the metal expansion electrode material is Ti / Al / Ni / Au or Ti / Pt / Au / Ti, and the electrode thickness is 500nm to 2μm, which plays the role of current expansion and electrical interconnection;

[0022] The thickness of each SiO2 dielectric layer is 200nm-350nm.

[0023] The present invention also provides a method for preparing the above structure, comprising the following steps:

[0024] Step 1, growing a first ohmic contact electrode on the upper surface of a GaN-based red, green and blue vertical stacked epitaxial film based on a sapphire substrate;

[0025] Step 2, bonding the GaN-based red, green and blue vertical stacked epitaxial thin film based on a sapphire substrate to a multi-layer glass carrier through a first ohmic contact electrode;

[0026] Step 3: Use laser to peel off the sapphire substrate to expose the green light N-type GaN;

[0027] Step 4, growing a second ohmic contact layer on the surface of the green light N-type GaN;

[0028] Step 5, photolithography and etching are performed using the pixel pattern of the InGaN red light emitting layer until the bonding layer is etched cleanly;

[0029] Step 6, performing dielectric passivation on the sidewalls of the stepped portion of the red light layer;

[0030] Step 7, photolithography and etching the pattern of the red and blue non-doped buffer layer until the red light N-type GaN is exposed;

[0031] Step 8: Perform patterning photolithography and electroplating of a metal extension layer on the red light N-type GaN, and connect the red light N-type GaN to a multi-layer glass substrate;

[0032] Step 9, forming a SiO2 dielectric layer above the red light N-type GaN metal extension layer for isolation;

[0033] Step 10, photolithography and etching are performed using the pixel pattern of the InGaN blue light emitting layer until the blue light P-type GaN is exposed;

[0034] Step 11, performing patterning photolithography and electroplating of a metal extension layer on the blue light P-type GaN, and connecting the blue light P-type GaN and the multi-layer glass carrier;

[0035] Step 12, passivating the InGaN blue light emitting layer and the SiO2 dielectric layer on the blue light P-type GaN side wall;

[0036] Step 13, photolithography and etching the pattern of the blue-green non-doped buffer layer until the green light N-type GaN is exposed;

[0037] Step 14, performing patterning photolithography and electroplating of a metal extension layer on the blue light N-type GaN, and connecting the blue light N-type GaN and the multi-layer glass carrier;

[0038] Step 15, forming a SiO2 dielectric layer on the metal extension layer of the blue light N-type GaN for isolation;

[0039] Step 16, photolithography and etching are performed using the pixel pattern of the InGaN green light emitting layer until the green light P-type GaN is exposed;

[0040] Step 17, performing patterning photolithography and electroplating of a metal extension layer on the green light P-type GaN, and connecting the green light P-type GaN and the multi-layer glass carrier;

[0041] Step 18, forming a SiO2 dielectric layer above the metal extension layer of the green light P-type GaN for isolation;

[0042] Step 19: Perform patterning photolithography and electroplating of a metal extension layer on the green light N-type GaN to connect the green light N-type GaN and the multi-layer glass substrate.

[0043] The present invention also provides a method for preparing the above structure, comprising the following steps:

[0044] Step 1, bonding a red light InGaN wafer based on a sapphire substrate and including a first ohmic contact electrode to a multi-layer glass carrier;

[0045] Step 2: Use laser to peel off the sapphire substrate of the red light InGaN wafer to expose the red light N-type GaN;

[0046] Step 3, growing a second ohmic contact layer on the surface of the red light N-type GaN to form a second ohmic contact electrode;

[0047] Step 4, bonding the blue light InGaN wafer based on a sapphire substrate and including the third ohmic contact electrode to the second ohmic contact electrode through a red and blue dielectric layer;

[0048] Step 5: Use laser to peel off the sapphire substrate of the blue light InGaN wafer to expose the blue light N-type GaN;

[0049] Step 6, growing a fourth ohmic contact layer on the surface of the blue light N-type GaN;

[0050] Step 7, bonding the green light InGaN wafer based on a sapphire substrate and including the fifth ohmic contact electrode to the fourth ohmic contact electrode through a blue-green dielectric layer;

[0051] Step 8: Laser stripping the sapphire substrate of the green light InGaN wafer to expose the green light N-type GaN;

[0052] Step 9, growing a sixth ohmic contact layer on the surface of the green light N-type GaN;

[0053] Step 10, photolithography and etching are performed using the pixel pattern of the InGaN red light emitting layer until the bonding layer is etched cleanly;

[0054] Step 11, passivating the SiO2 dielectric layer on the step sidewall of the red light layer;

[0055] Step 12, photolithography and etching the red and blue dielectric layer patterns until the second ohmic contact electrode is exposed;

[0056] Step 13, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the second ohmic contact electrode and the multi-layer glass substrate;

[0057] Step 14, forming a SiO2 dielectric layer on the metal extension layer of the second ohmic contact electrode for isolation;

[0058] Step 15, photolithography and etching are performed using the pixel pattern of the InGaN blue light emitting layer to expose the third ohmic contact electrode;

[0059] Step 16, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the third ohmic contact electrode and the multi-layer glass substrate;

[0060] Step 17, passivating the SiO2 dielectric layer on the step sidewalls of the blue light layer;

[0061] Step 18, photolithography and etching the blue-green dielectric layer pattern until the fourth ohmic contact electrode is exposed;

[0062] Step 19, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the fourth ohmic contact electrode and the multi-layer glass substrate;

[0063] Step 20: forming a SiO2 dielectric layer above the metal extension layer of the fourth ohmic contact electrode for isolation;

[0064] Step 21, photolithography and etching are performed using the pixel pattern of the InGaN green light emitting layer to expose the fifth ohmic contact electrode;

[0065] Step 22, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the fifth ohmic contact electrode and the multi-layer glass substrate;

[0066] Step 23, forming a SiO2 dielectric layer above the metal extension layer of the fifth ohmic contact electrode for isolation;

[0067] Step 24, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the sixth ohmic contact electrode and the multi-layer glass substrate;

[0068] Furthermore, when the GaN-based full-color pixel film is obtained based on GaN-based red, green and blue light vertical stacking epitaxy, the metal processes involved, including the growth of the first ohmic contact electrode and the second ohmic contact electrode, and the connection between the metal extension layer and the P-type GaN and the N-type GaN, all need to undergo an annealing process to achieve ohmic contact;

[0069] When the GaN-based full-color pixel film is obtained by bonding the red, green, and blue monochromatic GaN-based epitaxial films to the carrier respectively, the metal electrode ohmic contact process involved, including the electrode growth of the second ohmic contact layer, the fourth ohmic contact layer, and the sixth ohmic contact layer, all need to be annealed to achieve ohmic contact. Compared with the prior art, the beneficial effects of the present invention are:

[0070] (1) The GaN-based full-color pixel chip of the present invention is based on a vertical step-shaped stacking of red light layers, green light layers and blue light layers of different light-emitting sizes, and is connected to a driver IC chip through metal extension electrodes and a multi-layer glass substrate, respectively, for high refresh rate circuit driving, thereby achieving different colors of light emitted by the pixel chip at the same position in different time domains, achieving color display while increasing the resolution to three times that of the existing three-color sub-pixel lateral arrangement technology solution;

[0071] (2) The high-resolution and high-refresh rate Micro-LED device structure based on this scheme provides a specific preparation method, which can achieve high-yield and low-cost high-resolution and high-refresh rate Micro-LED device structure preparation, which is conducive to supporting the rapid advancement of Micro-LED industrialization and meets the strategic needs of the country's new generation of information technology industry for new displays.

[0072] The present invention is further described below in conjunction with specific implementation modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 This is a schematic diagram of the structure of a high-resolution and high-refresh rate Micro-LED device in Example 1 of the present invention.

[0074] Figure 2 This is a schematic diagram of the structure of a high-resolution and high-refresh rate Micro-LED device in Example 2 of the present invention.

[0075] Figure 3 Schematic diagram of the drive control process in embodiments 1 and 2 of the present invention.

[0076] Figure 4 Schematic diagram of the ARINC818 video data decoding module in Embodiments 1 and 2 of the present invention.

[0077] Figure 5 Schematic diagram of hierarchical scheduling and reading of SDRAM in embodiments 1 and 2 of the present invention.

[0078] Figure 6 Schematic diagram of driver cascade splicing in embodiments 1 and 2 of the present invention.

[0079] Figure 7 This is a timing diagram of RGB video field scanning in embodiments 1 and 2 of the present invention. DETAILED DESCRIPTION

[0080] In order to clearly describe the technical solution and the effects achieved by the present invention, the technical solution of the present invention is clearly explained below in combination with the accompanying drawings and specific embodiments of the present invention, so that technical personnel in the field can implement the invention without performing creative work. The structure shown in the accompanying drawings is not the entire actual structure but only a part of the actual structure. It should be noted that all other embodiments made by ordinary technical personnel in the field on the basis of the embodiments of the present invention without performing creative work should fall within the protection scope of the present invention.

[0081] The following examples are only for better explanation of the present invention, but the content of the present invention is not limited to the application in the examples. Therefore, those skilled in the art can make non-essential modifications to the implementation scheme based on the above invention content and apply it to other embodiments, which is still within the protection scope of the present invention. In addition, the experimental methods without specific conditions in the following examples should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the expressions in the text are not specially explained, they are only used for distinction and have no other meanings.

[0082] Example 1

[0083] Combination Figure 1 ,

[0084] A high-resolution and high-refresh rate Micro-LED device structure, including a GaN-based full-color pixel chip, a multi-layer glass carrier 12, and a driver IC chip 11;

[0085] The GaN-based full-color pixel chip is arranged at the upper end of the multi-layer glass carrier 12, and the driving IC chip 11 is arranged at the lower end of the glass carrier 12. In this embodiment, the multi-layer glass carrier 12 is a TVG glass carrier, which has multiple layers, including multiple layers of glass carriers (3-4 layers), and metal wiring layers (2-3 layers) between each glass carrier. The GaN-based full-color pixel chip and the driving IC chip 11 are vertically electrically connected through the metal wiring layers between the multi-layer glass carriers 12.

[0086] The GaN-based full-color pixel chip includes a red light layer, a blue light layer and a green light layer, wherein the red light layer, the blue light layer and the green light layer are stacked vertically in a stepped manner from bottom to top, and the light-emitting area decreases sequentially from bottom to top;

[0087] The driver IC chip 11 is connected to the GaN-based full-color pixel chip through a multi-layer glass carrier 12, and controls each light-emitting layer in the GaN-based full-color pixel chip respectively, that is, the video signal is transmitted through the optical fiber, and the Micro-LED field sequence scanning process is performed after analysis. The image splicing is performed by cascading the driver chips, which can realize the drive control of the high-resolution Micro-LED display screen and realize the color display of high resolution and high refresh rate.

[0088] In this embodiment, the GaN-based full-color pixel chip is obtained by a GaN-based full-color pixel film through a miniaturization process, and the GaN-based full-color pixel film is obtained based on GaN-based red, green and blue light vertical stacking epitaxy. The GaN-based full-color pixel chip is connected to the multi-layer glass carrier 12 through a metal bonding layer 13;

[0089] The GaN-based full-color pixel chip is based on the multi-layer glass substrate 12 and includes from bottom to top: a first ohmic contact electrode 14, a red light P-type GaN 15, an InGaN red light emitting layer 16, a red light N-type GaN 17, a red and blue non-doped buffer layer 18, a blue light P-type GaN 19, an InGaN blue light emitting layer 20, a blue light N-type GaN 21, a blue-green non-doped buffer layer 22, a green light P-type GaN 23, an InGaN green light emitting layer 24, a green light N-type GaN 25 and a second ohmic contact electrode 26;

[0090] In addition, each layer of the side wall of the GaN-based full-color pixel chip is provided with a metal extension electrode 27 connected to the multi-layer glass carrier 12, and a SiO2 dielectric layer 28 is provided between the metal extension electrodes 27 provided on the side wall of each layer. The dielectric layer 28 can be a SiO2 dielectric layer or a SiNx dielectric layer, and the thickness is 150nm to 350nm;

[0091] It can be seen that each light-emitting layer is stepped from bottom to top, and the step light-emitting area increases successively. Overall, the height of the red, blue and green light-emitting steps is generally 1μm to 1.8μm, and the red, blue and green light-emitting step area ratio is R (95~100): B (20~25): G (15~20), and the optimal ratio is 6.5:1.5:1.

[0092] In addition, the material of the metal expansion electrode 17 can be Ti / Al / Ni / Au or Ti / Pt / Au / Ti, and the electrode thickness is 500nm~2μm, which plays the role of current expansion and electrical interconnection. The thickness of each SiO2 dielectric layer is 200nm~350nm.

[0093] The InGaN red light peak wavelength described in this embodiment is 633nm±5nm, the InGaN blue light peak wavelength is 527nm±5nm, and the InGaN green light peak wavelength is 438nm±5nm; the non-doped buffer layer is AlN / AlGaN; each of the ohmic contact electrodes is an ITO film with a thickness of 100nm to 300nm.

[0094] Combination Figures 3 to 7 In this embodiment, the number of TGV glass carrier layers is 3, and the number of metal wiring layers is 2; the multi-layer glass carrier 12 is provided with circuit wiring for independent control of red, green and blue light, and the pixel driving method is: video signals are transmitted through optical fibers, and Micro-LED field sequential scanning is performed after analysis. The image splicing is performed by cascading driver chips, and high-resolution Micro-LED display drive control can be achieved. The pixel driving architecture includes four components: a driving control system, a video receiving unit, a field sequential scanning unit, and a picture splicing unit. The driving control system receives external fiber channel video signals and transmits them using the ARINC818 video interface.

[0095] The video is decoded and sent to FPGA. FPGA stores a frame of video data in SDRAM1, divides the data into n data areas according to certain rules, and stores them in different storage addresses of SDRAM2. In the read state, n groups of data are read at the same time and converted into the format required by the driver chip, and provided to the driver chip. After being processed by the driver chip, the output is displayed on the screen;

[0096] The video receiving unit reorganizes the received ARINC818 video data according to the image format definition and then outputs it. After receiving an FC-AV frame, a CRC check is performed, and video resolution information is extracted according to the protocol. By detecting the effective number of ARINC818 frame data and comparing it with the video resolution, the correctness of the ARINC818 transmitted video data is determined;

[0097] The field sequential scanning unit divides the synchronized video signal into n data areas according to the corresponding areas of the driver chip cascade, and writes them to n determined storage spaces of SDRAM2 in sequence. The key is the hierarchical scheduling and reading design of SDRAM, which requires n parallel read cache modules. RR polling scheduling can be used to read out n blocks of address data of SDRAM and put them in the cache area; the data of n cache areas are given at the same time in the read state;

[0098] The screen splicing unit adopts a cascade splicing mode. The chip can scan in both row and column directions at the same time. The chip is driven by a common cathode and outputs the video data through clock shift to the corresponding Micro-LED positive electrode. The RGB video signal is carried out in field sequence, and the scanning of one frame of R / G / B is completed each time.

[0099] In addition, the present invention also provides a method for preparing the above structure, comprising the following steps:

[0100] Step 1: A 100 nm thick first ohmic contact electrode 14, i.e., an ITO film, is grown on the upper surface of a GaN-based red, green, and blue light vertical stacking epitaxial film on a sapphire substrate, i.e., a red light P-type GaN 15, and annealed at 400° C. in an air atmosphere for 10 min;

[0101] Step 2, bonding the GaN-based red, green and blue vertical stacked epitaxial thin film based on the sapphire substrate to the multi-layer glass carrier 12 by Au / Sn at a temperature of 350° C. through the first ohmic contact electrode 14;

[0102] Step 3: Use laser to peel off the sapphire substrate to expose the green light N-type GaN25;

[0103] Step 4, growing a 200 nm thick second ohmic contact layer ITO film, i.e., the second ohmic contact electrode 26, on the surface of the green light N-type GaN 25, and annealing at 300° C. in an air atmosphere for 20 min;

[0104] Step 5: Photolithography and etching are performed using the pixel pattern of the InGaN red light emitting layer 16 until the Au / Sn bonding layer is etched cleanly;

[0105] Step 6: ALD is used to perform dielectric passivation on the sidewalls of the stepped portion of the red light layer to grow a dense SiO2 dielectric passivation layer;

[0106] Step 7, photolithography and etching the pattern of the red and blue non-doped buffer layer 18 until the red light N-type GaN 17 is exposed, over-etching 5 to 10 nm;

[0107] Step 8, perform patterning photolithography and electroplating of the metal extension layer on the red light N-type GaN 17, and connect the red light N-type GaN 17 and the multi-layer glass carrier 12;

[0108] Step 9: A 300nm thick SiO2 dielectric layer 28 is grown on the metal extension layer of the red light N-type GaN 17 for isolation;

[0109] Step 10, photolithography and etching are performed using the pixel pattern of the InGaN blue light emitting layer 20 until the blue light P-type GaN 19 is exposed, with an overetching of 5 to 10 nm;

[0110] Step 11, perform patterning photolithography and electroplating of a metal extension layer on the blue light P-type GaN19, connect the blue light P-type GaN19 and the multi-layer glass carrier 12, and anneal in an air atmosphere at 280°C for 20 minutes;

[0111] Step 12, passivating the InGaN blue light emitting layer 20 and the SiO2 dielectric layer on the side wall of the blue light P-type GaN 19; using ALD to grow a dense SiO2 dielectric passivation layer on the side wall of the stepped portion of the blue light layer;

[0112] Step 13, photolithography and etching the pattern of the blue-green non-doped buffer layer 22 until the blue light N-type GaN 21 is exposed, and the overetching is 5 to 10 nm;

[0113] Step 14, perform patterning photolithography and electroplating of the metal extension layer on the blue light N-type GaN 21, connect the blue light N-type GaN 21 and the multi-layer glass carrier 12, and anneal in a N2 atmosphere at 250°C for 10 minutes;

[0114] Step 15: Generate a 250nm thick SiO2 dielectric layer above the metal extension layer of the blue light N-type GaN21 for isolation;

[0115] Step 16, photolithography and etching are performed using the pixel pattern of the InGaN green light emitting layer 24 until the green light P-type GaN 23 is exposed, and the overetching is 5 to 10 nm;

[0116] Step 17, perform patterning photolithography and electroplating of a metal extension layer on the green light P-type GaN 23, and connect the green light P-type GaN 23 and the multi-layer glass carrier 12;

[0117] Step 18: Generate a 200nm thick SiO2 dielectric layer above the metal extension layer of the green light P-type GaN23 for isolation;

[0118] Step 19: Perform patterning photolithography and electroplating of the metal extension layer on the green light N-type GaN 25, connect the green light N-type GaN 25 and the multi-layer glass carrier 12, and anneal in a 200° C. N2 atmosphere for 10 minutes.

[0119] All metal processes involved in the above process, including the growth of the first ohmic contact electrode 14 and the second ohmic contact electrode 26 , and the connection between each metal extension layer and the P-type GaN and N-type GaN, need to be annealed to achieve ohmic contact.

[0120] Example 2

[0121] Reference Figure 2 , a high-resolution and high-refresh rate Micro-LED device structure, including a GaN-based full-color pixel chip, a multi-layer glass carrier 32, and a driver IC chip 31;

[0122] The GaN-based full-color pixel chip is arranged at the upper end of the multi-layer glass carrier, and the driving IC chip is arranged at the lower end of the glass carrier; in this embodiment, the multi-layer glass carrier 32 is a TVG glass carrier, which has multiple layers, including a multi-layer glass carrier (3-4 layers), and a metal wiring layer (2-3 layers) between each glass carrier. The GaN-based full-color pixel chip and the driving IC chip 31 are vertically electrically connected through the metal wiring layer between the multi-layer glass carrier 32.

[0123] The GaN-based full-color pixel chip includes a red light layer, a blue light layer and a green light layer, wherein the red light layer, the blue light layer and the green light layer are stacked vertically in a stepped manner from bottom to top, and the light-emitting area decreases sequentially from bottom to top;

[0124] The driver IC chip is connected to the GaN-based full-color pixel chip through a multi-layer glass carrier 32, and controls each light-emitting layer in the GaN-based full-color pixel chip respectively, that is, the video signal is transmitted through the optical fiber, and the Micro-LED field sequence scanning process is performed after analysis. By cascading the driver chips to perform image splicing, high-resolution Micro-LED display screen drive control can be realized, and high-resolution, high-refresh rate color display can be achieved.

[0125] In this embodiment, the GaN-based full-color pixel chip is obtained by a GaN-based full-color pixel film through a miniaturization process, and the GaN-based full-color pixel chip is connected to the multi-layer glass carrier 32 through a metal bonding layer 33;

[0126] The GaN-based full-color pixel chip includes, from bottom to top, based on the multi-layer glass carrier 12: a first ohmic contact electrode 34, a red light P-type GaN 35, an InGaN red light emitting layer 36, a red light N-type GaN 37, a second ohmic contact electrode 38, a red and blue dielectric layer 39, a third ohmic contact electrode 40, a blue light P-type GaN 41, an InGaN blue light emitting layer 42, a blue light N-type GaN 43, a fourth ohmic contact electrode 44, a blue-green dielectric layer 45, a fifth ohmic contact electrode 46, a green light P-type GaN 47, an InGaN green light emitting layer 48, a green light N-type GaN 49, and a sixth ohmic contact electrode 50.

[0127] In addition, each layer of the side wall of the GaN-based full-color pixel chip is provided with a metal extension electrode 51 connected to the multi-layer glass carrier 32, and a dielectric layer 52 is provided between the metal extension electrodes 51 provided on the side wall of each layer. The dielectric layer 52 can be a SiO2 dielectric layer or a SiNx dielectric layer with a thickness of 150nm to 350nm;

[0128] It can be seen that each light-emitting layer is stepped from bottom to top, and the step light-emitting area increases successively. Overall, the height of the red, blue and green light-emitting steps is generally 1μm to 1.8μm, and the red, blue and green light-emitting step area ratio is R (95~100): B (20~25): G (15~20), and the optimal ratio is 6.5:1.5:1.

[0129] In addition, the material of the metal expansion electrode 17 can be Ti / Al / Ni / Au or Ti / Pt / Au / Ti, and the electrode thickness is 500nm~2μm, which plays the role of current expansion and electrical interconnection. The thickness of each SiO2 dielectric layer is 200nm~350nm.

[0130] The InGaN red light peak wavelength described in this embodiment is 633nm±5nm, the InGaN blue light peak wavelength is 527nm±5nm, and the InGaN green light peak wavelength is 438nm±5nm; the non-doped buffer layer is AlN / AlGaN; each of the ohmic contact electrodes is an ITO film with a thickness of 100nm to 300nm.

[0131] Combination Figures 3 to 7 In this embodiment, the number of TGV glass carrier layers is 3, and the number of metal wiring layers is 2; the multi-layer glass carrier 32 is provided with circuit wiring for independent control of red, green and blue light, and the pixel driving method is: the video signal is transmitted through optical fiber, and the Micro-LED field sequence scanning process is performed after analysis. The picture splicing is performed by cascading the driver chips, and the high-resolution Micro-LED display drive control can be realized. The pixel driving architecture includes four components: a driving control system, a video receiving unit, a field sequence scanning unit, and a picture splicing unit. The driving control system receives the external fiber channel video signal and transmits it using the ARINC818 video interface.

[0132] The video is decoded and sent to FPGA. FPGA stores a frame of video data in SDRAM1, divides the data into n data areas according to certain rules, and stores them in different storage addresses of SDRAM2. In the read state, n groups of data are read at the same time and converted into the format required by the driver chip, and provided to the driver chip. After being processed by the driver chip, the output is displayed on the screen;

[0133] The video receiving unit reorganizes the received ARINC818 video data according to the image format definition and then outputs it. After receiving an FC-AV frame, a CRC check is performed, and video resolution information is extracted according to the protocol. By detecting the effective number of ARINC818 frame data and comparing it with the video resolution, the correctness of the ARINC818 transmitted video data is determined;

[0134] The field sequential scanning unit divides the synchronized video signal into n data areas according to the corresponding areas of the driver chip cascade, and writes them to n determined storage spaces of SDRAM2 in sequence. The key is the hierarchical scheduling and reading design of SDRAM, which requires n parallel read cache modules. RR polling scheduling can be used to read out n blocks of address data of SDRAM and put them in the cache area; the data of n cache areas are given at the same time in the read state;

[0135] The screen splicing unit adopts a cascade splicing mode. The chip can scan in both row and column directions at the same time. The chip is driven by a common cathode and outputs the video data through clock shift to the corresponding Micro-LED positive electrode. The RGB video signal is carried out in field sequence, and the scanning of one frame of R / G / B is completed each time.

[0136] In addition, the present invention also provides a method for preparing the above structure, comprising the following steps:

[0137] Step 1: bonding a red light InGaN wafer based on a sapphire substrate including a first ohmic contact electrode 34 to a multi-layer glass carrier 32;

[0138] Step 2: Use laser to peel off the sapphire substrate of the red light InGaN wafer to expose the red light N-type GaN35;

[0139] Step 3, growing a second ohmic contact layer of 200 nm thick ITO film on the surface of the red light N-type GaN 35 and annealing it in an air atmosphere at 320° C. for 10 minutes to form a second ohmic contact electrode 38;

[0140] Step 4: bonding the blue light InGaN wafer based on a sapphire substrate including the third ohmic contact electrode 40 to the second ohmic contact electrode 38 through the red-blue dielectric 39 layer at a temperature of 300° C.;

[0141] Step 5: Use laser to peel off the sapphire substrate of the blue light InGaN wafer to expose the blue light N-type GaN43;

[0142] Step 6: growing a fourth ohmic contact layer, i.e., a 150 nm thick ITO film, on the surface of the blue light N-type GaN 43 to form a fourth ohmic contact electrode 44;

[0143] Step 7, bonding the green light InGaN wafer based on a sapphire substrate including the fifth ohmic contact electrode 46 to the fourth ohmic contact electrode 44 through the blue-green dielectric layer 45 at a temperature of 250° C.;

[0144] Step 8: Laser stripping the sapphire substrate of the green light InGaN wafer to expose the green light N-type GaN49;

[0145] Step 9, growing a sixth ohmic contact layer on the green light N-type GaN surface 49, a 150 nm thick ITO film, and annealing for 20 min in an air atmosphere at 220° C. to form a sixth ohmic contact electrode 50;

[0146] Step 10, photolithography and etching are performed using the pixel pattern of the InGaN red light emitting layer until the Au / Sn bonding layer is etched cleanly;

[0147] Step 11, using PECVD to grow a SiO2 dielectric passivation layer on the step sidewalls of the red light layer;

[0148] Step 12, photolithography and etching are performed on the pattern of the red and blue dielectric layer 39 until the second ohmic contact electrode 38 is exposed, ensuring that there is no dielectric residue on the electrode surface;

[0149] Step 13, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the second ohmic contact electrode 38 and the multi-layer glass carrier 32;

[0150] Step 14, forming a 200 nm thick SiO2 dielectric layer on the metal extension layer of the second ohmic contact electrode 38 for isolation;

[0151] Step 15, photolithography and etching are performed using the pixel pattern of the InGaN blue light emitting layer 42 until the third ohmic contact electrode 40 is exposed, ensuring that there is no dielectric residue on the electrode surface;

[0152] Step 16, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the third ohmic contact electrode 40 and the multi-layer glass carrier 32;

[0153] Step 17, growing a SiO2 dielectric passivation layer on the step sidewalls of the blue light layer by using PECVD;

[0154] Step 18, photolithography and etching the pattern of the blue-green dielectric layer 45 until the fourth ohmic contact electrode 44 is exposed, ensuring that there is no dielectric residue on the electrode surface;

[0155] Step 19, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the fourth ohmic contact electrode 44 and the multi-layer glass carrier 32;

[0156] Step 20, forming a 250 nm thick SiO2 dielectric layer above the metal extension layer of the fourth ohmic contact electrode 44 for isolation;

[0157] Step 21, photolithography and etching are performed using the pixel pattern of the InGaN green light emitting layer 48 to expose the fifth ohmic contact electrode 46;

[0158] Step 22, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the fifth ohmic contact electrode 46 and the multi-layer glass substrate;

[0159] Step 23, forming a 300 nm thick SiO2 dielectric layer above the metal extension layer of the fifth ohmic contact electrode for isolation;

[0160] Step 24, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the sixth ohmic contact electrode 50 and the multi-layer glass carrier 32;

[0161] The metal electrode ohmic contact process involved in the above process, including the electrode growth of the second ohmic contact layer, the fourth ohmic contact layer and the sixth ohmic contact layer, all need to undergo an annealing process to achieve ohmic contact.

[0162] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A high-resolution and high-refresh rate Micro-LED device structure, characterized in that: Including GaN-based full-color pixel chip, multi-layer glass substrate, and driver IC chip; The GaN-based full-color pixel chip is arranged on the upper end of the multi-layer glass carrier, and the driver IC chip is arranged on the lower end of the glass carrier; The GaN-based full-color pixel chip includes a red light layer, a blue light layer and a green light layer, wherein the red light layer, the blue light layer and the green light layer are stacked vertically in a stepped manner from bottom to top, and the light-emitting area decreases sequentially from bottom to top; The driver IC chip is connected to the GaN-based full-color pixel chip through a multi-layer glass carrier, and controls each light-emitting layer in the GaN-based full-color pixel chip respectively, so as to realize high-resolution and high-refresh-rate color display.

2. The high-resolution and high-refresh rate Micro-LED device structure according to claim 1, characterized in that: The GaN-based full-color pixel chip is obtained by a miniaturization process of a GaN-based full-color pixel film, and the GaN-based full-color pixel film is obtained based on GaN-based red, green and blue light vertical stacking epitaxy, or by bonding red, green and blue monochrome GaN-based epitaxial films to a carrier respectively.

3. The high-resolution and high-refresh rate Micro-LED device structure according to claim 2, characterized in that: When the GaN-based full-color pixel film is obtained based on GaN-based red, green and blue light vertical stacking epitaxy: The GaN-based full-color pixel chip includes, from bottom to top, based on a multi-layer glass carrier, a first ohmic contact electrode, a red P-type GaN, an InGaN red light emitting layer, a red N-type GaN, a red and blue non-doped buffer layer, a blue P-type GaN, an InGaN blue light emitting layer, a blue N-type GaN, a blue-green non-doped buffer layer, a green P-type GaN, an InGaN green light emitting layer, a green N-type GaN and a second ohmic contact electrode.

4. The high-resolution and high-refresh rate Micro-LED device structure according to claim 2, characterized in that: When the GaN-based full-color pixel film is obtained by bonding red, green, and blue single-color GaN-based epitaxial films to a carrier respectively: The GaN-based full-color pixel chip includes, from bottom to top, based on a multi-layer glass carrier: a first ohmic contact electrode, a red light P-type GaN, an InGaN red light emitting layer, a red light N-type GaN, a second ohmic contact electrode, a red and blue dielectric layer, a third ohmic contact electrode, a blue light P-type GaN, an InGaN blue light emitting layer, a blue light N-type GaN, a fourth ohmic contact electrode, a blue-green dielectric layer, a fifth ohmic contact electrode, a green light P-type GaN, an InGaN green light emitting layer, a green light N-type GaN, and a sixth ohmic contact electrode.

5. The high-resolution and high-refresh rate Micro-LED device structure according to claim 3 or 4, characterized in that: The light emitting area ratio of the red light layer, the blue light layer and the green light layer is 6.5:1.5:

1.

6. The high-resolution and high-refresh rate Micro-LED device structure according to claim 1, characterized in that: Each side wall of the GaN-based full-color pixel chip is provided with a metal extension electrode connected to the multi-layer glass carrier; A SiO2 dielectric layer is arranged between the metal extension electrodes arranged on the side walls of each layer.

7. The high-resolution and high-refresh rate Micro-LED device structure according to claim 6, characterized in that: The metal expansion electrode material is Ti / Al / Ni / Au or Ti / Pt / Au / Ti, and the electrode thickness is 500nm to 2μm, which plays the role of current expansion and electrical interconnection; The thickness of each SiO2 dielectric layer is 200nm-350nm.

8. The method for preparing the structure according to claim 3, characterized in that: The following steps are involved: Step 1, growing a first ohmic contact electrode on the upper surface of a GaN-based red, green and blue vertical stacked epitaxial film based on a sapphire substrate; Step 2, bonding the GaN-based red, green and blue vertical stacked epitaxial thin film based on a sapphire substrate to a multi-layer glass carrier through a first ohmic contact electrode; Step 3: Use laser to peel off the sapphire substrate to expose the green light N-type GaN; Step 4, growing a second ohmic contact layer on the surface of the green light N-type GaN; Step 5, photolithography and etching are performed using the pixel pattern of the InGaN red light emitting layer until the bonding layer is etched cleanly; Step 6, performing dielectric passivation on the sidewalls of the stepped portion of the red light layer; Step 7, photolithography and etching the pattern of the red and blue non-doped buffer layer until the red light N-type GaN is exposed; Step 8: Perform patterning photolithography and electroplating of a metal extension layer on the red light N-type GaN, and connect the red light N-type GaN to a multi-layer glass substrate; Step 9, forming a SiO2 dielectric layer above the red light N-type GaN metal extension layer for isolation; Step 10, photolithography and etching are performed using the pixel pattern of the InGaN blue light emitting layer until the blue light P-type GaN is exposed; Step 11, performing patterning photolithography and electroplating of a metal extension layer on the blue light P-type GaN, and connecting the blue light P-type GaN and the multi-layer glass carrier; Step 12, passivating the InGaN blue light emitting layer and the SiO2 dielectric layer on the blue light P-type GaN side wall; Step 13, photolithography and etching the pattern of the blue-green non-doped buffer layer until the green light N-type GaN is exposed; Step 14, performing patterning photolithography and electroplating of a metal extension layer on the blue light N-type GaN, and connecting the blue light N-type GaN and the multi-layer glass carrier; Step 15, forming a SiO2 dielectric layer on the metal extension layer of the blue light N-type GaN for isolation; Step 16, photolithography and etching are performed using the pixel pattern of the InGaN green light emitting layer until the green light P-type GaN is exposed; Step 17, performing patterning photolithography and electroplating of a metal extension layer on the green light P-type GaN, and connecting the green light P-type GaN and the multi-layer glass carrier; Step 18, forming a SiO2 dielectric layer above the metal extension layer of the green light P-type GaN for isolation; Step 19: Perform patterning photolithography and electroplating of a metal extension layer on the green light N-type GaN to connect the green light N-type GaN and the multi-layer glass substrate.

9. The method for preparing the structure according to claim 4, characterized in that: The following steps are involved: Step 1, bonding a red light InGaN wafer based on a sapphire substrate and including a first ohmic contact electrode to a multi-layer glass carrier; Step 2: Use laser to peel off the sapphire substrate of the red light InGaN wafer to expose the red light N-type GaN; Step 3, growing a second ohmic contact layer on the surface of the red light N-type GaN to form a second ohmic contact electrode; Step 4, bonding the blue light InGaN wafer based on a sapphire substrate and including the third ohmic contact electrode to the second ohmic contact electrode through a red and blue dielectric layer; Step 5: Use laser to peel off the sapphire substrate of the blue light InGaN wafer to expose the blue light N-type GaN; Step 6, growing a fourth ohmic contact layer on the surface of the blue light N-type GaN; Step 7, bonding the green light InGaN wafer based on a sapphire substrate and including the fifth ohmic contact electrode to the fourth ohmic contact electrode through a blue-green dielectric layer; Step 8: Laser stripping the sapphire substrate of the green light InGaN wafer to expose the green light N-type GaN; Step 9, growing a sixth ohmic contact layer on the surface of the green light N-type GaN; Step 10, photolithography and etching are performed using the pixel pattern of the InGaN red light emitting layer until the bonding layer is etched cleanly; Step 11, passivating the SiO2 dielectric layer on the step sidewall of the red light layer; Step 12, photolithography and etching the red and blue dielectric layer patterns until the second ohmic contact electrode is exposed; Step 13, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the second ohmic contact electrode and the multi-layer glass substrate; Step 14, forming a SiO2 dielectric layer on the metal extension layer of the second ohmic contact electrode for isolation; Step 15, photolithography and etching are performed using the pixel pattern of the InGaN blue light emitting layer to expose the third ohmic contact electrode; Step 16, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the third ohmic contact electrode and the multi-layer glass substrate; Step 17, passivating the SiO2 dielectric layer on the step sidewalls of the blue light layer; Step 18, photolithography and etching the blue-green dielectric layer pattern until the fourth ohmic contact electrode is exposed; Step 19, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the fourth ohmic contact electrode and the multi-layer glass substrate; Step 20: forming a SiO2 dielectric layer above the metal extension layer of the fourth ohmic contact electrode for isolation; Step 21, photolithography and etching are performed using the pixel pattern of the InGaN green light emitting layer to expose the fifth ohmic contact electrode; Step 22, performing pattern photolithography and electroplating connection on the metal extension layer pattern connecting the fifth ohmic contact electrode and the multi-layer glass substrate; Step 23, forming a SiO2 dielectric layer above the metal extension layer of the fifth ohmic contact electrode for isolation; Step 24: perform pattern photolithography and electroplating connection on the metal extension layer pattern connecting the sixth ohmic contact electrode and the multi-layer glass substrate.

10. The preparation method according to claim 8 or 9, characterized in that: When the GaN-based full-color pixel film is obtained based on GaN-based red, green and blue light vertical stacking epitaxy, the metal processes involved, including the growth of the first ohmic contact electrode and the second ohmic contact electrode, and the connection between the metal extension layer and the P-type GaN and the N-type GaN, all need to undergo an annealing process to achieve ohmic contact; When the GaN-based full-color pixel film is obtained by bonding red, green and blue monochrome GaN-based epitaxial films to a carrier respectively, the metal electrode ohmic contact process involved, including the electrode growth of the second ohmic contact layer, the fourth ohmic contact layer and the sixth ohmic contact layer, all need to undergo an annealing process to achieve ohmic contact.

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