Nitride full-color integrated miniature light-emitting diode display chip and preparation method thereof

Abstract

The invention discloses a nitride full-color integrated miniature light-emitting diode display chip and a preparation method thereof, a columnar or halfpace-shaped table surface is formed on the surface of a silicon substrate, and then an AlN buffer layer, an AlGaN stress modulation layer, an n-type GaN layer, an InGaN / GaN composite quantum well layer and a p-type conductive layer sequentially extend on the table surface of the silicon substrate to form a miniature light-emitting diode table surface; through stress release of the side wall of the mesa and stress modulation of the AlGaN layer, tensile stress distribution which is gradually reduced from the center of the mesa to the outer ring is formed in the n-type GaN layer, so that indium component distribution in the InGaN / GaN composite quantum well layer is regulated and controlled, and the micro light-emitting diode mesa covering three primary color wavebands of red, green and blue is formed. According to the chip structure disclosed by the invention, the red, green and blue three-primary-color sub-pixels are integrated, and the difficulty of a mass transfer process of the full-color micro light-emitting diode display chip is reduced. According to the invention, the preparation of the red, green and blue three-primary-color sub-pixels can be completed only by implementing an epitaxial process once, and the process flow is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of full-color micro light-emitting diode display, and particularly to a nitride full-color integrated micro light-emitting diode display chip and a preparation method thereof. Background Art

[0002] Micro light-emitting diode display technology has the advantages of low energy consumption, long lifespan, and good color rendering, and has broad application prospects in the fields of large-screen displays, consumer electronics, in-vehicle displays, virtual reality / augmented reality, and wearable displays. How to achieve full-color display is one of the challenges faced by micro light-emitting diode display technology. Currently, the method of mass transfer is usually used to transfer red, green, and blue primary color micro light-emitting diode chips onto the same substrate to achieve full-color display.

[0003] Generally, full-color micro light-emitting diode display requires millions of red, green, and blue primary color pixels, and it is very difficult to accurately transfer and integrate such a large number of micro light-emitting diode chips. Therefore, it is difficult to improve the yield of the mass transfer process, which limits the development of full-color micro light-emitting diode display technology. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a nitride full-color integrated micro light-emitting diode display chip and a preparation method thereof. The chip structure integrates red, green, and blue primary color sub-pixels, greatly reducing the technical difficulty of mass transfer of full-color display chips.

[0005] To achieve the above purpose, the present invention provides the following solutions: A nitride full-color integrated micro light-emitting diode display chip, comprising: a transparent substrate, a transparent electrode bonding layer, and a mesa array composed of a single or several micro light-emitting diode mesas; The micro light-emitting diode mesa or the silicon substrate mesa array is connected to the transparent substrate through the transparent electrode bonding layer.

[0006] Preferably, the micro light-emitting diode mesa is columnar or frustum-shaped; the width range of the micro light-emitting diode mesa is from 100 nm to 100 μm; the mesa pitch range of the micro light-emitting diode mesa is from 100 nm to 100 μm.

[0007] Preferably, the structure of the micro light-emitting diode mesa sequentially includes, from the transparent substrate and the transparent electrode bonding layer: an n-type transparent electrode layer, an n-type GaN layer, one or several periods of InGaN / GaN composite multi-quantum well layers, a p-type conductive layer, and a p-type electrode layer.

[0008] Preferably, the n-type GaN layer shows a tensile stress distribution trend that gradually decreases from the center of the mesa to the outer circle.

[0009] Preferably, each period of the InGaN / GaN composite multiple quantum well layer includes: a plurality of InGaN / GaN quantum wells with a high indium content and a plurality of InGaN / GaN quantum wells with a low indium content; the central region of the micro light-emitting diode mesa is dominated by the InGaN / GaN quantum wells with a high indium content; the outer ring region of the micro light-emitting diode mesa is dominated by the InGaN / GaN quantum wells with a low indium content.

[0010] Preferably, from the central region to the outer ring region of the micro light-emitting diode mesa, the indium composition of the InGaN well layer in the InGaN / GaN composite multiple quantum well layer shows a gradually decreasing distribution trend; from the central region to the outer ring region of the micro light-emitting diode mesa, the emission wavelength of the InGaN / GaN quantum wells with a high indium content gradually blue-shifts from 630 nm to 550 nm; from the central region to the outer ring region of the micro light-emitting diode mesa, the emission wavelength of the InGaN / GaN quantum wells with a low indium content gradually blue-shifts from 550 nm to 450 nm.

[0011] Preferably, the emission wavelength range of the micro light-emitting diode mesa covers the red, green, and blue primary color bands; the light-emitting regions corresponding to the red, green, and blue primary color bands in the micro light-emitting diode mesa are annularly distributed; the annular region with a light-emitting center wavelength range of 610 to 630 nm in the micro light-emitting diode mesa is the red photon pixel region; the annular region with a light-emitting center wavelength range of 510 to 530 nm in the micro light-emitting diode mesa is the green photon pixel region; the annular region with a light-emitting center wavelength range of 450 to 470 nm in the micro light-emitting diode mesa is the blue photon pixel region.

[0012] Preferably, the p-type conductive layer includes: a p-type AlGaN electron blocking layer and a p-type GaN layer; The p-type conductive layer located between the red photon pixel region, the green photon pixel region, and the blue photon pixel region is transformed into a high-resistance layer by ion implantation; the p-type conductive layer located on the red photon pixel region, the green photon pixel region, and the blue photon pixel region is not subjected to ion implantation treatment.

[0013] Preferably, the p-type electrode layer is annularly distributed; The p-type electrode layer is located on the surface of the p-type conductive layer that has not been subjected to ion implantation treatment.

[0014] Preferably, a method for preparing a nitride full-color integrated micro light-emitting diode display chip includes: S1. Provide a raw silicon substrate with a (111) crystal plane on the surface; S2. Use photolithography and etching processes to etch the surface of the original silicon substrate in step S1 into a silicon substrate mesa array with columnar or trapezoidal shapes; the height of the mesas in the silicon substrate mesa array ranges from 10 μm to 100 μm; the width of the silicon substrate mesa array ranges from 10 μm to 100 μm; the spacing of the silicon substrate mesa array ranges from 10 μm to 100 μm; S3. Use a metalorganic chemical vapor deposition equipment to epitaxially grow an AlN buffer layer, an AlGaN stress modulation layer, and the n-type GaN layer in sequence on the silicon substrate mesa array prepared in step S2 to obtain an n-type GaN mesa array, and adjust the structural parameters of the AlGaN stress modulation layer according to the stress release effect on the mesa sidewalls, so that the n-type GaN mesa prepared in step S3 is in a tensile stress state with a central high and outer low distribution trend; the structural composition of the AlGaN stress modulation layer includes one or more of a uniform composition AlGaN structure, a graded composition AlGaN structure, an AlN / AlGaN superlattice structure, an AlGaN / GaN superlattice structure, and an AlN / GaN superlattice structure; S4. Epitaxially grow one or several periods of the InGaN / GaN composite multiple quantum well layer on the n-type GaN mesa array prepared in step S3, and each period of the InGaN / GaN composite multiple quantum well layer includes several high-indium-content InGaN / GaN quantum wells and several low-indium-content InGaN / GaN quantum wells; S5. Epitaxially grow the p-type conductive layer on the InGaN / GaN composite multiple quantum well layer in step S4 to obtain a nitride micro light-emitting diode mesa array; the p-type conductive layer includes a p-type AlGaN electron blocking layer and a p-type GaN layer; S6. According to the principle that tensile stress promotes the incorporation of indium atoms into the lattice, by optimizing the morphology parameters of the silicon substrate mesa in step S2 and the structural parameters of the AlGaN stress modulation layer in step S3, control the tensile stress distribution trend of the n-type GaN mesa in step S3, so that the indium composition of the InGaN well layer in the InGaN / GaN composite multiple quantum well layer prepared in step S4 gradually decreases from the central region to the outer region of the mesa; optimize the epitaxial growth parameters of the InGaN / GaN composite multiple quantum well layer in step S4, so that from the central region to the outer region of the micro light-emitting diode mesa formed in steps S1 to S5, the emission wavelength of the high-indium-content InGaN / GaN quantum wells gradually blue-shifts from 630 nm to 550 nm, and the emission wavelength of the low-indium-content InGaN / GaN quantum wells gradually blue-shifts from 550 nm to 450 nm; the emission wavelength of the micro light-emitting diode mesa formed in steps S1 to S5 covers the red, green, and blue primary color bands for display applications from the central region to the outer region of the mesa; S7. Determine the red photon pixel region, the green photon pixel region, and the blue photon pixel region; the light-emitting regions corresponding to the three primary colors of red, green, and blue in the micro-light-emitting diode mesa are annularly distributed; the annular region with a light-emitting center wavelength range of 610 to 630 nm in the micro-light-emitting diode mesa is the red photon pixel region; the annular region with a light-emitting center wavelength range of 510 to 530 nm in the micro-light-emitting diode mesa is the green photon pixel region; the annular region with a light-emitting center wavelength range of 450 to 470 nm in the micro-light-emitting diode mesa is the blue photon pixel region; S8. Use photolithography, metal evaporation, and stripping processes to deposit the annular p-type electrode layer on the red photon pixel region, the green photon pixel region, and the blue photon pixel region of the micro-light-emitting diode mesa prepared in steps S1 to S6; S9. Use the p-type electrode layer prepared in step S8 as a mask for ion implantation process to convert the non-mask-covered region between the red photon pixel region, the green photon pixel region, and the blue photon pixel region into the high-resistance layer; S10. Bond the micro-light-emitting diode mesa array prepared in step S9 to the temporary substrate; S11. Use an alkaline etching solution to remove the original silicon substrate and fix the micro-light-emitting diode mesa array on the temporary substrate; S12. Use photolithography and etching processes to remove the AlN buffer layer and the AlGaN stress modulation layer in the micro-light-emitting diode mesa in step S11; S13. Use photolithography, metal evaporation, and stripping processes to deposit the n-type transparent electrode layer and the transparent electrode bonding layer on the n-type GaN layer exposed in step S12; S14. Bond the micro-light-emitting diode mesa array deposited with the n-type transparent electrode layer and the transparent electrode bonding layer to the transparent substrate; S15. Remove the temporary substrate in step S10; S16. Cut the micro-light-emitting diode mesa array on the transparent substrate prepared in steps S1 to S15 into chips; each chip includes: a single or several silicon substrate mesa arrays composed of the micro-light-emitting diode mesas.

[0015] The present invention discloses the following technical effects: The present invention provides a nitride full-color integrated micro light-emitting diode display chip and a preparation method thereof. By integrating red, green, and blue primary color sub-pixels on the same micro light-emitting diode mesa, the present invention solves the problem of difficult mass transfer of full-color micro light-emitting diode display chips, realizes full-color micro light-emitting diode display with high pixel density and improves the full-color mixing effect; by means of a micro light-emitting diode mesa with a vertical structure, the problems of poor injection efficiency and optoelectronic performance of conventional light-emitting chips are solved, and stronger light-emitting intensity and optoelectronic performance are realized; by designing a chip preparation method, the problem of low chip yield caused by multiple epitaxies of conventional chips is solved, and the preparation of red, green, and blue primary color InGaN / GaN composite multiple quantum wells is completed based on a single epitaxy process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 Schematic diagram of a nitride full-color micro light-emitting diode display chip provided by an embodiment of the present invention; Figure 2 Cross-sectional schematic diagram of a nitride full-color micro light-emitting diode display chip provided by an embodiment of the present invention; Figure 3 Top view schematic diagram of a nitride full-color micro light-emitting diode display chip provided by an embodiment of the present invention; Figure 4 Cross-sectional schematic diagram of the surface of a silicon substrate etched into a mesa array provided by an embodiment of the present invention; Figure 5 Cross-sectional schematic diagram of a nitride micro light-emitting diode structure epitaxially grown on a silicon substrate mesa array provided by an embodiment of the present invention; Figure 6 Top view schematic diagram of a nitride micro light-emitting diode structure epitaxially grown on a silicon substrate mesa array provided by an embodiment of the present invention; Figure 7 Cross-sectional schematic diagram of a p-type electrode layer deposited on the red, green, and blue sub-pixel regions of a micro light-emitting diode mesa provided by an embodiment of the present invention; Figure 8 Top view schematic diagram of a p-type electrode layer deposited on the red, green, and blue sub-pixel regions of a micro light-emitting diode mesa provided by an embodiment of the present invention; Figure 9Schematic cross-sectional view of a micro light-emitting diode mesa array after isolating red, green, and blue primary color sub-pixel devices under a p-type electrode layer mask provided by an embodiment of the present invention; Figure 10 Schematic cross-sectional view of a micro light-emitting diode mesa array bonded to a temporary substrate provided by an embodiment of the present invention; Figure 11 Schematic cross-sectional view of a micro light-emitting diode mesa array after etching away the silicon substrate provided by an embodiment of the present invention; Figure 12 Schematic cross-sectional view of a micro light-emitting diode mesa array after etching away the AlN buffer layer and the AlGaN stress modulation layer provided by an embodiment of the present invention; Figure 13 Schematic cross-sectional view of a micro light-emitting diode mesa array after depositing an n-type transparent electrode layer and a transparent electrode bonding layer provided by an embodiment of the present invention; Figure 14 Schematic cross-sectional view of a micro light-emitting diode mesa array bonded to a transparent substrate provided by an embodiment of the present invention; Figure 15 Schematic cross-sectional view of a micro light-emitting diode mesa array after removing the temporary substrate provided by an embodiment of the present invention.

[0018] Explanation of reference numerals: 101 - Original silicon substrate, 102 - Silicon substrate mesa, 201 - AlN buffer layer, 202 - AlGaN stress modulation layer, 203 - n-type GaN layer, 204 - InGaN / GaN composite multi-quantum well layer, 205 - p-type conductive layer, 301 - Red photon pixel region, 302 - Green photon pixel region, 303 - Blue photon pixel region, 401 - p-type electrode layer, 601 - High-resistance region, 701 - Temporary substrate, 801 - Temporary bonding layer, 1001 - n-type transparent electrode layer, 1002 - Transparent electrode bonding layer, 1101 - Transparent substrate. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] The purpose of the present invention is to provide a nitride full-color integrated micro light-emitting diode display chip and a preparation method thereof. The chip structure integrates red, green, and blue primary color sub-pixels, greatly reducing the technical difficulty of massive transfer of full-color display chips.

[0021] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] As Figure 1 and Figure 2 shown, the structure of the nitride full-color integrated micro light-emitting diode display chip in the embodiment of the present invention includes a transparent substrate 1101, a transparent electrode bonding layer 1002, and a mesa array composed of 4 columnar micro light-emitting diode mesas. The micro light-emitting diode mesa array is connected to the transparent substrate through the transparent electrode bonding layer.

[0023] As Figure 2 shown, the mesa width of the micro light-emitting diode mesa is 50 μm, and the mesa pitch is 80 μm.

[0024] As Figure 2 shown, in the micro light-emitting diode mesa structure, successively from the transparent substrate and the transparent electrode bonding layer upwards, it includes: an n-type transparent electrode layer 1001, an n-type GaN layer 203, 3 cycles of InGaN / GaN composite multiple quantum well layers 204, a p-type conductive layer 205, and a p-type electrode layer 401.

[0025] Specifically, the tensile stress in the n-type GaN layer in the micro light-emitting diode mesa structure shows a distribution trend of being high in the mesa center and low in the outer ring.

[0026] Further, each cycle of the InGaN / GaN composite multiple quantum well layer in the micro light-emitting diode mesa structure includes 1 high-indium-content InGaN / GaN quantum well and 2 low-indium-content InGaN / GaN quantum wells. In the central region of the micro light-emitting diode mesa, the high-indium-content InGaN / GaN quantum well dominates the light emission; in the outer ring region of the micro light-emitting diode mesa, the low-indium-content InGaN / GaN quantum well dominates the light emission.

[0027] Specifically, from the central region to the outer ring region of the micro light-emitting diode mesa, the indium composition of the InGaN quantum well layer in the InGaN / GaN composite multiple quantum well layer shows a gradually decreasing distribution trend. Among them, the indium composition of the InGaN quantum well layer in the high-indium-content InGaN / GaN quantum well gradually decreases from 40% to 31%, while the indium composition of the InGaN quantum well layer in the low-indium-content InGaN / GaN quantum well gradually decreases from 31% to 17%. Correspondingly, the emission wavelength of the high-indium-content InGaN / GaN quantum well gradually blue-shifts from 630 nm to 550 nm, while the emission wavelength of the low-indium-content InGaN / GaN quantum well gradually blue-shifts from 550 nm to 450 nm.

[0028] As Figure 3As shown, on the micro light-emitting diode mesa, a ring-shaped region with a luminescence center wavelength in the range of 610 - 630 nm is defined as the red photon pixel region 301, a ring-shaped region with a luminescence center wavelength in the range of 510 - 530 nm is defined as the green photon pixel region 302, and a ring-shaped region with a luminescence center wavelength in the range of 450 - 470 nm is defined as the blue photon pixel region 303.

[0029] Furthermore, the p-type conductive layer in the micro light-emitting diode mesa structure includes a p-type AlGaN electron blocking layer and a p-type GaN layer; as Figure 2 and Figure 4 shown, the p-type conductive layer between the red, green, and blue primary color sub-pixel regions is transformed into a high-resistance layer 601 through ion implantation to achieve device isolation between sub-pixels; while the p-type conductive layer above the red, green, and blue primary color sub-pixel regions is not subjected to ion implantation treatment.

[0030] Specifically, the p-type electrode layer in the micro light-emitting diode mesa structure is annularly distributed on the surface of the p-type conductive layer that has not been subjected to ion implantation treatment, namely, respectively above the red, green, and blue primary color sub-pixels.

[0031] As Figures 4 to 15 shown, the preparation method of the nitride full-color integrated micro light-emitting diode display chip of the present invention includes the following steps: S1. Provide an original silicon substrate 101 with a (111) crystal plane surface, a thickness of 1.5 mm, and a diameter of 200 mm.

[0032] S2. As Figure 4 shown, use photolithography and etching processes to etch the surface of the original silicon substrate 101 in step 1 into an array of columnar or trapezoidal mesas 102. The height of the mesa is 20 μm, the width of the mesa is 50 μm, and the mesa pitch is 80 μm.

[0033] S3. As Figure 5 shown, use a metalorganic chemical vapor deposition device to sequentially epitaxially grow a 300-nm-thick AlN buffer layer 201, a 300-nm-thick Al 0.5 Ga 0.5 N stress modulation layer 202 and a 2-μm-thick n-type GaN layer 203 on the silicon substrate mesa array prepared in step S2 to form an n-type GaN mesa array. Due to the stress release effect on the mesa sidewalls, the tensile stress distribution in the n-type GaN mesa shows a trend of being high in the center and low in the outer circle.

[0034] S4. On the n-type GaN mesa array prepared in step S3, continue to epitaxially grow 3 cycles of InGaN / GaN composite multiple quantum well layers 204. Each cycle of the InGaN / GaN composite multiple quantum well layer includes 1 high-indium-content InGaN / GaN quantum well and 2 low-indium-content InGaN / GaN quantum wells. Due to the stress distribution trend of the n-type GaN mesa formed in step S3, the indium atom lattice incorporation efficiency of the InGaN / GaN composite multiple quantum well layer gradually decreases from the center to the outer ring. The indium composition of the InGaN well layer gradually decreases from the mesa center region to the outer ring region, while the emission wavelength of the InGaN / GaN composite multiple quantum well gradually blueshifts from the mesa center region to the outer ring region. In the mesa center region, the indium atom lattice incorporation efficiency is high, the epitaxial quality of the high-indium-content InGaN / GaN quantum well is relatively high, and the high-indium-content InGaN / GaN quantum well dominates the emission. In the mesa outer ring region, the indium atom lattice incorporation efficiency is insufficient, the epitaxial quality of the high-indium-content InGaN / GaN quantum well is poor, and the low-indium-content InGaN / GaN quantum well dominates the emission.

[0035] S5. On the basis of step S4, continue to epitaxially grow a p-type conductive layer 205, including a p-type AlGaN electron blocking layer and a p-type GaN layer, to form a micro light-emitting diode mesa array.

[0036] S6. Optimize the height and width of the silicon substrate mesa in step S2, the aluminum composition and thickness of the AlGaN stress modulation layer in step S3, and the indium composition and thickness of the InGaN well layer of the high-indium-content and low-indium-content InGaN / GaN quantum wells in step S4, so that the emission wavelength of the high-indium-content InGaN / GaN quantum well gradually blueshifts from 630 nm to 550 nm from the micro light-emitting diode mesa center region to the outer ring region, while the emission wavelength of the low-indium-content InGaN / GaN quantum well gradually blueshifts from 550 nm to 450 nm.

[0037] S7. Through cathode fluorescence spectroscopy, scan and test the emission wavelength distribution of the micro light-emitting diode mesa array formed in steps S1 - S6. As Figure 6 shown, define the annular region with the emission center wavelength in the range of 610 - 630 nm as the red photon pixel region 301, the annular region with the emission center wavelength in the range of 510 - 530 nm as the green photon pixel region 302, and the annular region with the emission center wavelength in the range of 450 - 470 nm as the blue photon pixel region 303.

[0038] S8. As Figure 7 and Figure 8 shown, use photolithography, metal deposition, and stripping processes to deposit a three-loop annular Ni / Au metal stack as the p-type electrode layer 401 on the micro light-emitting diode mesa array prepared in steps S1 - S6, coveringFigure 6 The surfaces of the red, green, and blue photon pixel regions shown in

[0039] S9. As shown in Figure 9 Using the p-type electrode layer prepared in step S8 as a mask, an Ar + ion implantation process is carried out. The dose of Ar + ions is 4×10 12 cm -2 , and the energy is 40 keV, so that the p-type conductive layer between the red, green, and blue primary color sub-pixels without mask coverage is transformed into a high-resistance region 601, thereby realizing device isolation between the red, green, and blue sub-pixels.

[0040] S10. As shown in Figure 10 , the micro light-emitting diode mesa array prepared in step S9 is bonded to the temporary substrate 701.

[0041] S11. As shown in Figure 11 , the silicon substrate is removed by etching with a KOH solution, and the micro light-emitting diode mesa array remains on the temporary substrate. In the micro light-emitting diode mesa structure on the temporary substrate, from bottom to top are the temporary bonding layer 801, the p-type electrode layer 401, the p-type conductive layer 205, the InGaN / GaN composite multi-quantum well layer 204, the n-type GaN layer 203, the AlGaN stress modulation layer 202, and the AlN buffer layer 201.

[0042] S12. As shown in Figure 12 , the AlN buffer layer and the AlGaN stress modulation layer in the micro light-emitting diode mesa structure in step S11 are removed by using photolithography and etching processes to expose the n-type GaN layer 203.

[0043] S13. As shown in Figure 13 , an ITO thin film is deposited on the exposed n-type GaN layer in the micro light-emitting diode mesa structure in step S12 as the n-type transparent electrode layer 1001 and an Au metal layer as the transparent electrode bonding layer 1002.

[0044] S14. As shown in Figure 14 , the micro light-emitting diode mesa array deposited with the n-type transparent electrode layer and the transparent electrode bonding layer is bonded to the transparent substrate 1101.

[0045] S15. As shown in Figure 15 , the temporary substrate described in step S10 is removed.

[0046] S16. The micro light-emitting diode mesa array on the transparent substrate prepared in steps S1 to S15 is cut into chips; each chip includes a mesa array composed of 4 micro light-emitting diode mesas, that is, it realizes as shown in Figure 2 and3 The nitride full-color integrated micro light-emitting diode display chip shown in the figure.

[0047] The beneficial effects of the present invention are as follows: (1) The nitride full-color integrated micro light-emitting diode display chip disclosed in the present invention integrates red, green, and blue primary color sub-pixels, greatly reducing the difficulty of the mass transfer process of the full-color micro light-emitting diode display chip.

[0048] (2) The red, green, and blue sub-pixels of the nitride full-color integrated micro light-emitting diode display chip disclosed in the present invention are located on the same micro light-emitting diode mesa, having a high integration degree, which is beneficial to realizing a full-color micro light-emitting diode display with a high pixel density and improving the full-color mixing effect.

[0049] (3) The nitride full-color integrated micro light-emitting diode display chip disclosed in the present invention has a vertically structured micro light-emitting diode mesa, which is beneficial to improving the current injection efficiency and optoelectronic performance of the micro light-emitting diode device.

[0050] (4) For the preparation method of the nitride full-color integrated micro light-emitting diode display chip disclosed in the present invention, only one epitaxial process needs to be implemented to complete the preparation of the red, green, and blue primary color InGaN / GaN composite multiple quantum wells, thus simplifying the process flow.

[0051] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same and similar parts among the embodiments, reference can be made to each other.

[0052] Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A nitride full-color integrated micro light-emitting diode display chip, characterized in that: include: A transparent substrate, a transparent electrode bonding layer, and a table array composed of a single or several micro light emitting diode tables; The micro light emitting diode table or the silicon substrate table array is connected to the transparent substrate through the transparent electrode bonding layer.

2. A nitride full-color integrated micro light-emitting diode display chip according to claim 1, characterized in that: The micro-LED mesas are columnar or terraced; the width of the micro-LED mesas ranges from 100nm to 100μm; and the mesas spacing of the micro-LED mesas ranges from 100nm to 100μm.

3. A nitride full-color integrated micro light-emitting diode display chip according to claims 1 and 2, characterized in that: The structure of the micro-LED mesa includes, from the transparent substrate and the transparent electrode bonding layer, an n-type transparent electrode layer, an n-type GaN layer, one or several periods of InGaN / GaN composite multi-quantum well layers, a p-type conductive layer and a p-type electrode layer.

4. A nitride full-color integrated micro light-emitting diode display chip according to claims 1 to 3, characterized in that: The n-type GaN layer presents a tensile stress distribution trend that gradually decreases from the center of the table to the outer circle.

5. A nitride full-color integrated micro light-emitting diode display chip according to claims 1 to 4, characterized in that: The InGaN / GaN composite multi-quantum well layer of each period includes: a plurality of InGaN / GaN quantum wells with high indium content and a plurality of InGaN / GaN quantum wells with low indium content; the central area of ​​the micro-light-emitting diode table is dominated by the InGaN / GaN quantum wells with high indium content for luminescence; and the outer ring area of ​​the micro-light-emitting diode table is dominated by the InGaN / GaN quantum wells with low indium content for luminescence.

6. A nitride full-color integrated micro light-emitting diode display chip according to claims 1 to 5, characterized in that: From the central area to the outer circle area of ​​the micro-light-emitting diode mesa, the indium component of the InGaN potential well layer in the InGaN / GaN composite multi-quantum well layer presents a gradually decreasing distribution trend; from the central area to the outer circle area of ​​the micro-light-emitting diode mesa, the emission wavelength of the high-indium-content InGaN / GaN quantum well gradually blue-shifts from 630nm to 550nm; from the central area to the outer circle area of ​​the micro-light-emitting diode mesa, the emission wavelength of the low-indium-content InGaN / GaN quantum well gradually blue-shifts from 550nm to 450nm.

7. A nitride full-color integrated micro light-emitting diode display chip according to claims 1 to 6, characterized in that: The light-emitting wavelength range of the micro-LED table covers the red, green and blue primary color bands; the light-emitting areas corresponding to the red, green and blue primary color bands in the micro-LED table are distributed in a ring shape; the ring-shaped area with a light-emitting center wavelength range of 610 to 630nm in the micro-LED table is a red photon pixel area; the ring-shaped area with a light-emitting center wavelength range of 510 to 530nm in the micro-LED table is a green photon pixel area; the ring-shaped area with a light-emitting center wavelength range of 450 to 470nm in the micro-LED table is a blue photon pixel area.

8. A nitride full-color integrated micro light-emitting diode display chip according to claims 1 to 7, characterized in that: The p-type conductive layer comprises: a p-type AlGaN electron blocking layer and a p-type GaN layer; The p-type conductive layer located between the red light sub-pixel region, the green light sub-pixel region, and the blue light sub-pixel region is transformed into a high-resistance layer through ion implantation; the p-type conductive layer located on the red light sub-pixel region, the green light sub-pixel region, and the blue light sub-pixel region is not subjected to ion implantation.

9. A nitride full-color integrated micro light-emitting diode display chip according to claims 1 to 8, characterized in that: The p-type electrode layer is distributed in a ring shape; The p-type electrode layer is located on the surface of the p-type conductive layer that has not been subjected to ion implantation treatment.

10. A method for preparing a nitride full-color integrated micro light-emitting diode display chip, characterized in that: A nitride full-color integrated micro-light emitting diode display chip as described in any one of claims 1 to 9, the method comprising: S1, providing an original silicon substrate with a (111) crystal plane; S2, using photolithography and etching processes to etch the surface of the original silicon substrate in step S1 into a columnar or terraced silicon substrate mesa array; the height of the mesa in the silicon substrate mesa array ranges from 10 μm to 100 μm; the width of the silicon substrate mesa array ranges from 10 μm to 100 μm; the spacing of the silicon substrate mesa array ranges from 10 μm to 100 μm; S3, using metal organic chemical vapor deposition equipment, sequentially epitaxially growing an AlN buffer layer, an AlGaN stress modulation layer and the n-type GaN layer on the silicon substrate mesa array prepared in step S2 to obtain an n-type GaN mesa array, and adjusting the structural parameters of the AlGaN stress modulation layer according to the stress release effect of the mesa sidewall, so that the n-type GaN mesa prepared in step S3 is in a tensile stress state with a distribution trend of high in the center and low in the outer circle; the structural composition of the AlGaN stress modulation layer includes: a uniform composition AlGaN structure, a gradient composition AlGaN structure, an AlN / AlGaN superlattice structure, an AlGaN / GaN superlattice structure, and one or more of an AlN / GaN superlattice structure; S4, epitaxially growing one or several periods of the InGaN / GaN composite multi-quantum well layer on the n-type GaN mesa array prepared in step S3, wherein each period of the InGaN / GaN composite multi-quantum well layer comprises: several InGaN / GaN quantum wells with high indium content and several InGaN / GaN quantum wells with low indium content; S5, epitaxially growing the p-type conductive layer on the InGaN / GaN composite multi-quantum well layer in step S4 to obtain a nitride micro-light emitting diode mesa array; the p-type conductive layer includes: the p-type AlGaN electron blocking layer and the p-type GaN layer; S6. According to the principle that tensile stress promotes the incorporation of indium atoms into the crystal lattice, by optimizing the morphological parameters of the silicon substrate table in step S2 and the structural parameters of the AlGaN stress modulation layer in step S3, the tensile stress distribution trend of the n-type GaN table in step S3 is regulated, so that the indium component of the InGaN potential well layer of the InGaN / GaN composite multi-quantum well layer prepared in step S4 gradually decreases from the central area of ​​the table to the outer area; the epitaxial growth of the InGaN / GaN composite multi-quantum well layer in step S4 is optimized. The length parameters are such that from the central area to the outer ring area of ​​the micro-LED mesa formed in steps S1 to S5, the emission wavelength of the high indium content InGaN / GaN quantum well gradually blue-shifts from 630nm to 550nm, and the emission wavelength of the low indium content InGaN / GaN quantum well gradually blue-shifts from 550nm to 450nm; the emission wavelength of the micro-LED mesa formed in steps S1 to S5 covers the red, green and blue primary color bands for display applications from the central area to the outer ring area of ​​the mesa; S7, determining the red light sub-pixel area, the green light sub-pixel area, and the blue light sub-pixel area; S8, using photolithography, metal evaporation and lift-off processes, depositing the annular p-type electrode layer on the red sub-pixel region, the green sub-pixel region and the blue sub-pixel region of the micro-LED mesa prepared in steps S1 to S6; S9, performing an ion implantation process using the p-type electrode layer prepared in step S8 as a mask to transform the mask-uncovered area between the red sub-pixel area, the green sub-pixel area, and the blue sub-pixel area into the high-resistance layer; S10, bonding the micro light emitting diode mesa array prepared in step S9 to a temporary substrate; S11, using an alkaline etching solution to remove the original silicon substrate, and fixing the micro light emitting diode mesa array on the temporary substrate; S12, using photolithography and etching processes to remove the AlN buffer layer and the AlGaN stress modulation layer in the micro light emitting diode mesa in step S11; S13, depositing the n-type transparent electrode layer and the transparent electrode bonding layer on the n-type GaN layer exposed in step S12 by using photolithography, metal evaporation and lift-off processes; S14, bonding the micro light emitting diode mesa array on which the n-type transparent electrode layer and the transparent electrode bonding layer are deposited to the transparent substrate; S15, removing the temporary substrate in step S10; S16, cutting the micro-LED mesa array on the transparent substrate prepared in steps S1 to S15 into chips; each chip includes: a single or multiple silicon substrate mesa arrays composed of the micro-LED mesas.

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