Preparation method of nitride miniature resonant cavity light-emitting diode chip and nitride miniature resonant cavity light-emitting diode chip

Abstract

The invention belongs to the technical field of micro light-emitting diode display, and provides a preparation method of a nitride micro resonant cavity light-emitting diode chip and the chip. The method comprises the steps of preparation of a first distributed Bragg reflector array unit, selective area epitaxial growth, preparation of a nitride light-emitting diode epitaxial structure, evaporation of a P-type transparent electrode layer, preparation of a second distributed Bragg reflector lamination, deposition of an N-type electrode layer and a metal thickening layer, and chip cutting. According to the preparation method disclosed by the invention, a substrate stripping process does not need to be used, the preparation process of the nitride miniature resonant cavity light emitting diode chip is simplified, the cavity length of the resonant cavity can be remarkably shortened, the light emitting directivity and the light emitting intensity of the nitride miniature resonant cavity light emitting diode chip are enhanced, the light emitting peak line width is reduced, and the light emitting efficiency is improved. Therefore, the high-performance nitride miniature resonant cavity light-emitting diode chip is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of micro light emitting diode display, and in particular to a preparation method of a nitride micro resonant cavity light emitting diode chip and the chip. Background Art

[0002] Micro-LED display technology, characterized by self-luminous pixels, holds broad application prospects in a wide range of applications, including virtual reality and augmented reality displays, consumer electronics, automotive displays, televisions, wearable displays, and large-screen displays, thanks to its excellent color rendering performance, high resolution, exceptional reliability, low energy consumption, fast response speed, and long operating life. Nitride semiconductor materials, with their emission wavelengths covering the entire visible light band, are ideal for achieving full-color micro-LED displays. However, nitride semiconductor micro-LEDs exhibit a large half-width at half-maximum (HWHM), which becomes increasingly pronounced as the wavelength increases. This severely impacts the color gamut of micro-LED displays, making them unable to meet the demands of high color purity and wide color gamut displays. Resonant cavity light-emitting diodes (RCLEDs) employ an optical resonant cavity in the light-emitting layer to modulate the localized photon density of states and selectively enhance emission at specific wavelengths. This effectively reduces the HWHM, enhances light directionality and intensity, and contributes to improved color rendering performance in full-color micro-LED displays. The optical resonant cavity of a nitride semiconductor RCD consists of distributed Bragg reflectors on either side of the light-emitting layer.

[0003] However, the traditional preparation process requires peeling off the epitaxial semiconductor substrate of the nitride semiconductor light-emitting diode. This is not only complicated, but also limited by the total thickness of the epitaxial layer, making it difficult to further reduce the length of the resonant cavity, resulting in multiple longitudinal modes in the spectrum and reducing the light output intensity, thereby limiting the performance improvement of the resonant cavity light-emitting diode device. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention aims to provide a method for preparing a nitride micro-resonant cavity light-emitting diode chip and the chip, so as to solve the problems that the prior art requires a substrate peeling process and has a long resonant cavity length.

[0005] To achieve the above object, the present invention provides the following solutions: A method for preparing a nitride micro-resonant cavity light-emitting diode chip, comprising: Providing a preset substrate, and sequentially preparing an N-type nitride layer and a first distributed Bragg reflector stack on the preset substrate; Etching the first distributed Bragg reflector stack into a periodic array to obtain a first distributed Bragg reflector array, so as to form a selective epitaxial window of the N-type nitride layer between units of the first distributed Bragg reflector array; performing selective epitaxy of the N-type nitride layer in the selective epitaxial window, controlling the N-type nitride layer in the selective epitaxial window to grow laterally toward the first distributed Bragg reflector array region by adjusting growth parameters, and achieving growth closure on units of the first distributed Bragg reflector array to obtain a first distributed Bragg reflector array buried layer structure; sequentially growing a light-emitting layer and a P-type nitride layer on the first distributed Bragg reflector array buried layer structure to obtain a nitride light-emitting diode epitaxial structure, defining a pixel area, and growing an arrayed metal layer on the surface of the pixel area; Using the metal layer as a mask, the P-type nitride layer in the spacer region of the array unit of the metal layer is transformed into an insulating region 701 by an ion implantation process, and the metal layer is removed by using an acidic solution; Vapor-depositing a P-type transparent electrode layer on the surface of the nitride light-emitting diode epitaxial structure treated by the ion implantation process; preparing a second distributed Bragg reflector stack on the P-type transparent electrode layer in the pixel area, so that the second distributed Bragg reflector stack and the first distributed Bragg reflector array buried layer structure form a resonant cavity; defining a P-type electrode region, removing the P-type transparent electrode layer, the P-type nitride layer, and the light-emitting layer in areas other than the P-type electrode region and the pixel region, defining the exposed N-type nitride layer as the N-type electrode region, depositing an N-type electrode layer on the surface of the N-type electrode region, and depositing a metal thickening layer on the surface of the P-type electrode region, to obtain a nitride micro-resonant cavity light-emitting diode structure; The nitride micro-resonant cavity light-emitting diode structure is cut into chips to obtain nitride micro-resonant cavity light-emitting diode chips.

[0006] Preferably, the pixel region includes one or more units of the first distributed Bragg reflector array and spacing regions between array units.

[0007] Preferably, the preset substrate is any one of a sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon substrate, a silicon carbide substrate, a gallium oxide substrate, a gallium nitride composite template, and an aluminum nitride composite template; the N-type nitride layer is a stack composed of one or more of InN, GaN, AlN, InGaN, and AlGaN of N-type conductivity type; the first distributed Bragg reflector stack structure is a periodic arrangement of two dielectric materials with different refractive indices; the light-emitting layer is a periodic multi-quantum well structure composed of two or more of InN, GaN, AlN, InGaN, and AlGaN; the P-type nitride layer is a stack composed of one or more of InN, GaN, AlN, InGaN, and AlGaN of P-type conductivity type; the second distributed Bragg reflector stack is a periodic arrangement of two dielectric materials with different refractive indices.

[0008] Preferably, the unit size range of the first distributed Bragg reflector array unit is 0.1 μm to 100 μm; the array unit spacing range of the first distributed Bragg reflector array unit is 0.1 μm to 100 μm; the thickness range of the N-type nitride layer on the first distributed Bragg reflector array buried layer structure is 0.01 μm to 10 μm.

[0009] Preferably, the reflectivity of the first distributed Bragg reflector stack structure to the target wavelength is higher than 90%; and the reflectivity of the second distributed Bragg reflector stack to the target wavelength ranges from 50% to 90%.

[0010] Preferably, the array units of the metal layer and the units of the first distributed Bragg reflector array in the pixel area are distributed in the same manner.

[0011] Preferably, the P-type electrode region is distributed in a ring shape, surrounding the pixel region.

[0012] Preferably, a nitride micro resonant cavity light emitting diode chip is prepared by the aforementioned method for preparing a nitride micro resonant cavity light emitting diode chip.

[0013] The present invention discloses the following technical effects: The present invention provides a method for preparing a nitride micro-resonant cavity light-emitting diode chip and the chip. By introducing a distributed Bragg reflector buried layer into the nitride light-emitting diode structure through the selective area epitaxy technology, the problem of low process yield caused by the need for a substrate peeling process in the existing preparation process is solved, thereby simplifying the preparation process. The problem that the existing process is difficult to effectively shorten the cavity length of the resonant cavity is solved, and the selectivity of emission at a specific wavelength is enhanced, as well as the directionality and intensity of the light output are improved. The lateral growth and growth closure of the N-type nitride layer are used to solve the defect of high dislocation density in the light-emitting layer of the existing process, thereby improving the luminous efficiency of the nitride micro-resonant cavity light-emitting diode device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 A schematic diagram of the process for preparing a nitride micro-resonant cavity light-emitting diode chip according to an embodiment of the present invention; Figure 2 A schematic cross-sectional view of a sample structure after the first distributed Bragg reflector stack deposition is completed, provided in an embodiment of the present invention; Figure 3 A schematic cross-sectional view and a schematic top view of a sample structure after the first distributed Bragg reflector stack array is completed, provided in an embodiment of the present invention; Figure 4 A schematic cross-sectional view of a sample structure after completion of selective epitaxy and lateral growth of an N-type nitride layer according to an embodiment of the present invention; Figure 5 A schematic cross-sectional view of a sample structure after epitaxy of a nitride light-emitting diode light-emitting layer and a P-type nitride layer is completed, provided in an embodiment of the present invention; Figure 6 A schematic top view of the definition of a pixel region of a nitride micro-resonant cavity light-emitting diode provided by an embodiment of the present invention; Figure 7 A schematic cross-sectional view and a schematic top view of a sample structure after arrayed metal layer deposition provided by an embodiment of the present invention; Figure 8 A schematic cross-sectional view and a schematic top view of a sample structure after the ion implantation process is completed according to an embodiment of the present invention; Figure 9 A schematic cross-sectional view of a sample structure after deposition of a P-type transparent electrode layer according to an embodiment of the present invention; Figure 10 A schematic cross-sectional view and a schematic top view of a sample structure after deposition of a second distributed Bragg reflector stack provided in an embodiment of the present invention; Figure 11 A schematic top view of the definition of the P-type electrode region of a nitride micro-resonant cavity light-emitting diode provided in an embodiment of the present invention; Figure 12 A schematic cross-sectional view and a schematic top view of the sample structure after etching of the area outside the P-type electrode region and the pixel region provided in an embodiment of the present invention; Figure 13 Schematic cross-sectional view and top view of the sample structure after the deposition of the N-type electrode layer and the metal thickening layer provided in an embodiment of the present invention.

[0016] Description of reference numerals: 101-preset substrate, 102-N-type nitride layer, 103-first distributed Bragg reflector stack, 201-first distributed Bragg reflector array unit, 202-selective epitaxial window, 301-first distributed Bragg reflector array buried layer structure, 401-light-emitting layer, 402-P-type nitride layer, 501-pixel area, 601-metal layer, 701-insulating area, 801-P-type transparent electrode layer, 901-second distributed Bragg reflector stack, 1001-P-type electrode area, 1101-N-type electrode area, 1201-N-type electrode layer, 1202-metal thickening layer. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] The purpose of the present invention is to provide a method for preparing a nitride micro-resonant cavity light-emitting diode chip and the chip, so as to solve the problems that the existing process requires a substrate peeling process and the resonant cavity is long.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a schematic diagram of a process for preparing a nitride micro resonant cavity light-emitting diode chip according to an embodiment of the present invention. The present invention provides a method for preparing a nitride micro resonant cavity light-emitting diode chip, comprising: Figure 2A schematic cross-sectional view of a sample structure after the first distributed Bragg reflector stack 103 is deposited is provided in an embodiment of the present invention. Figure 2 As shown, a preset substrate 101 is provided, and an N-type nitride layer 102 and a first distributed Bragg reflector stack 103 are sequentially formed on the preset substrate 101; Figure 3 The cross-sectional schematic diagram and top view schematic diagram of the sample structure after the arraying of the first distributed Bragg reflector stack 103 are provided in an embodiment of the present invention, as shown in FIG. Figure 3 As shown, the first distributed Bragg reflector stack 103 is etched into a periodic array to obtain a first distributed Bragg reflector array, so as to form a selective epitaxial window 202 of the N-type nitride layer 102 between the first distributed Bragg reflector array units 201; Figure 4 A schematic cross-sectional view of the sample structure after the selective epitaxy and lateral growth of the N-type nitride layer 102 are completed according to an embodiment of the present invention, as shown in FIG. Figure 4 As shown, selective epitaxy of the N-type nitride layer 102 is performed in the selective epitaxy window 202, and the N-type nitride layer 102 in the selective epitaxy window 202 is controlled to grow laterally toward the first distributed Bragg reflector array region by adjusting growth parameters, and growth closure is achieved on the first distributed Bragg reflector array unit 201, thereby obtaining a first distributed Bragg reflector array buried layer structure 301; Figure 5 A schematic cross-sectional view of a sample structure after epitaxy of a nitride light-emitting diode light-emitting layer 401 and a P-type nitride layer 402 is provided in an embodiment of the present invention. Figure 5 As shown, a light-emitting layer 401 and a P-type nitride layer 402 are sequentially grown on the first distributed Bragg reflector array buried structure 301 to obtain a nitride light-emitting diode epitaxial structure; Figure 6 A top view schematic diagram of the definition of a pixel region 501 of a nitride micro-resonant cavity light-emitting diode provided in an embodiment of the present invention is shown as follows: Figure 6 As shown, a pixel area 501 is defined; Figure 7 The cross-sectional schematic diagram and top view schematic diagram of the sample structure after the arrayed metal layer 601 is deposited are provided in an embodiment of the present invention. Figure 7 As shown, an arrayed metal layer 601 is grown on the surface of the pixel area 501; Figure 8 The cross-sectional schematic diagram and top view schematic diagram of the sample structure after the ion implantation process is completed according to the embodiment of the present invention are as follows: Figure 8As shown, the metal layer 601 is used as a mask to transform the P-type nitride layer 402 in the spacer region of the array unit of the metal layer 601 into an insulating region 701 by an ion implantation process, and the metal layer 601 is removed by an acidic solution; Figure 9 A schematic cross-sectional view of the sample structure after the deposition of the P-type transparent electrode layer 801 is provided in an embodiment of the present invention. Figure 9 As shown, a P-type transparent electrode layer 801 is evaporated on the surface of the nitride light-emitting diode epitaxial structure treated by the ion implantation process; Figure 10 The cross-sectional schematic diagram and top view schematic diagram of the sample structure after the second distributed Bragg reflector stack 901 is deposited are provided in an embodiment of the present invention, as shown in FIG. Figure 10 As shown, a second distributed Bragg reflector stack 901 is prepared on the P-type transparent electrode layer 801 of the pixel area 501, so that the second distributed Bragg reflector stack 901 and the first distributed Bragg reflector array buried layer structure 301 form a resonant cavity; Figure 11 A top view schematic diagram of the definition of the P-type electrode region 1001 of the nitride micro-resonant cavity light-emitting diode provided in an embodiment of the present invention is shown as follows: Figure 11 As described above, a P-type electrode region 1001 is defined; Figure 12 The cross-sectional schematic diagram and top view schematic diagram of the sample structure after etching of the area outside the P-type electrode area 1001 and the pixel area 501 are provided in an embodiment of the present invention, as shown in FIG. Figure 12 As shown, the P-type transparent electrode layer 801, the P-type nitride layer 402, and the light-emitting layer 401 in the area other than the P-type electrode area 1001 and the pixel area 501 are removed, and the exposed N-type nitride layer 102 is determined as the N-type electrode area 1101; Figure 13 The cross-sectional schematic diagram and top view schematic diagram of the sample structure after the N-type electrode layer 1201 and the metal thickening layer 1202 are deposited are provided in the embodiment of the present invention. Figure 13 As shown, an N-type electrode layer 1201 is deposited on the surface of the N-type electrode region 1101, and a metal thickening layer 1202 is deposited on the surface of the P-type electrode region 1001 to obtain a nitride micro-resonant cavity light emitting diode structure; The nitride micro-resonant cavity light-emitting diode structure is cut into chips to obtain nitride micro-resonant cavity light-emitting diode chips.

[0021] Furthermore, the pixel area 501 includes one or more of the first distributed Bragg reflector array units 201 and spacing areas between the array units.

[0022] Specifically, the array units of the metal layer 601 and the first distributed Bragg reflector array units 201 in the pixel area 501 are distributed in the same manner.

[0023] Preferably, the P-type electrode region 1001 is distributed in a ring shape, surrounding the pixel region 501 .

[0024] Furthermore, the preset substrate 101 is any one of a sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon substrate, a silicon carbide substrate, a gallium oxide substrate, a gallium nitride composite template, and an aluminum nitride composite template; the N-type nitride layer 102 is a stack composed of one or more of InN, GaN, AlN, InGaN, and AlGaN of N-type conductivity type; the first distributed Bragg reflector stack 103 structure is formed by a periodic arrangement of two dielectric materials with different refractive indices; the number of periods of the first distributed Bragg reflector stack 103 structure ranges from 1 to 100; the light-emitting layer 401 is I A periodic multi-quantum well structure composed of two or more of nN, GaN, AlN, InGaN, and AlGaN; the number of periods of the light-emitting layer 401 ranges from 1 to 10; the periodic thickness of the light-emitting layer 401 ranges from 5nm to 50nm; the P-type nitride layer 402 is a stack composed of one or more of InN, GaN, AlN, InGaN, and AlGaN of P-type conductivity type; the second distributed Bragg reflector stack 901 is formed by a periodic arrangement of two dielectric materials with different refractive indices; the number of periods of the second distributed Bragg reflector stack 901 ranges from 1 to 100.

[0025] Specifically, the total thickness of the N-type nitride layer 102 ranges from 0.1 μm to 10 μm; the unit size of the first distributed Bragg reflector array unit 201 ranges from 0.1 μm to 100 μm; the array unit pitch of the first distributed Bragg reflector array unit 201 ranges from 0.1 μm to 100 μm; the thickness of the N-type nitride layer 102 on the first distributed Bragg reflector array buried structure 301 ranges from 0.01 μm to 10 μm; and the thickness of the P-type transparent electrode layer 801 ranges from 0.01 μm to 1 μm.

[0026] Preferably, the reflectivity of the first distributed Bragg reflector stack 103 structure to the target wavelength is higher than 90%; the target wavelength range is 200nm to 700nm; the reflectivity of the second distributed Bragg reflector stack 901 to the target wavelength range is 50% to 90%.

[0027] Optionally, a nitride micro resonant cavity light emitting diode chip is prepared by the aforementioned method for preparing a nitride micro resonant cavity light emitting diode chip.

[0028] Specifically, the following is a further detailed description with reference to the accompanying drawings and specific embodiments. Figures 2 to 13 As shown, the method for preparing a nitride micro-resonant cavity light-emitting diode chip includes the following steps: S1 Figure 2 As shown, a c-plane sapphire substrate is provided, and a 25 nm aluminum nitride film is sputtered on the surface of the c-plane sapphire substrate using a physical vapor deposition device to form an aluminum nitride composite template (corresponding to the preset substrate 101).

[0029] S2 Figure 2 As shown, a metal organic chemical vapor deposition device is used to grow an N-type GaN layer (corresponding to the N-type nitride layer 102 ) with a thickness of 2 μm on the aluminum nitride composite template described in S1 .

[0030] S3 Figure 2 As shown, an ion beam sputtering coating device is used to evaporate a first distributed Bragg reflector stack 103 on the surface of the N-type GaN layer prepared in S2; the first distributed Bragg reflector stack 103 includes silicon dioxide and tantalum pentoxide with a period number of 6.5, a total thickness of approximately 1.2 μm, and a reflectivity of 97.525% for a target wavelength of 625 nm.

[0031] S4 Figure 3 As shown, the first distributed Bragg reflector stack 103 prepared in S3 is etched into a periodic array using processes such as photolithography, etching and corrosion; the first distributed Bragg reflector array unit 201 described in this step is a cylinder with a diameter of 4 μm, and the array units are distributed in a square lattice with a spacing of 10 μm; a selective epitaxial window 202 of the N-type GaN layer is formed between the first distributed Bragg reflector array units 201 described in this step.

[0032] S5 Figure 4 As shown, a metal organic chemical vapor deposition device is used to perform selective epitaxial growth of an N-type GaN layer in the growth window described in S4, and the growth parameters are adjusted so that the N-type GaN layer in the growth window area grows laterally toward the first distributed Bragg reflector array area described in S4, and the growth is closed on the first distributed Bragg reflector array to form a first distributed Bragg reflector array buried layer structure 301; the thickness of the N-type GaN layer on the first distributed Bragg reflector array buried layer structure 301 described in this step is approximately 1.6μm.

[0033] S6 Figure 5As shown, a nitride light-emitting diode light-emitting layer 401 and a P-type GaN layer (corresponding to the P-type nitride layer 402) are grown on the N-type GaN layer on the first distributed Bragg reflector array buried layer structure 301 described in S5 to obtain a nitride light-emitting diode epitaxial structure; the light-emitting layer 401 structure described in this step is a 3-period InGaN / GaN multi-quantum well structure with a period thickness of 13nm and a light-emitting wavelength of 625nm; the thickness of the P-type GaN layer described in this step is approximately 0.2μm.

[0034] S7 Figure 6 As shown, a pixel area 501 of a nitride micro-resonant cavity light-emitting diode is defined; the pixel area 501 described in this step includes 2×2 array units of the first distributed Bragg reflector array buried layer structure 301 and corresponding array unit spacing areas.

[0035] S8 Figure 7 As shown, using photolithography and metal evaporation processes, an arrayed Ti metal layer (corresponding to the metal layer 601) with a thickness of 100 nm is formed on the surface of the pixel area 501 defined in S7. The distribution of the array units of the Ti metal layer is consistent with the distribution of the array units of the first distributed Bragg reflector array buried layer structure 301 in the pixel area 501 defined in S7.

[0036] S9 Figure 8 As shown, the Ti metal layer described in S8 is used as a mask to perform Ar + Ion implantation process, Ar + The ion dose is 4×10 12 cm -2 , with an energy of 40 keV, so that the P-type GaN layer in the array unit spacer region of the first distributed Bragg reflector array buried layer structure 301 in the pixel area 501 described in S7 is transformed into a high-resistance layer (corresponding to the insulating region 701), and then the Ti metal layer described in S8 is removed using an acidic solution to expose the surface of the nitride light-emitting diode epitaxial structure described in S6.

[0037] S10 Figure 9 As shown, an ITO layer with a thickness of 100 nm is evaporated on the surface of the nitride light-emitting diode epitaxial structure as the P-type transparent electrode layer 801 .

[0038] S11 Figure 10As shown, an ion beam sputtering coating device is used to prepare a second distributed Bragg reflector stack 901 on the ITO layer of the pixel area 501 defined in S7; the second distributed Bragg reflector stack 901 described in this step includes 2 periods of silicon dioxide and tantalum pentoxide, and has a reflectivity of 78% for a target wavelength of 625nm; the second distributed Bragg reflector stack 901 described in this step and the first distributed Bragg reflector array buried layer structure 301 described in S3 form a resonant cavity, thereby forming a nitride micro resonant cavity light emitting diode structure.

[0039] S12 Figure 11 As shown, a P-type electrode region 1001 of the nitride micro-resonant cavity light-emitting diode is defined; the P-type electrode region 1001 described in this step is distributed in a ring shape, surrounding the pixel region 501 defined in S7.

[0040] S13 Figure 12 As shown, the ITO layer, the P-type GaN layer and the light-emitting layer 401 in the area outside the P-type electrode region 1001 defined in S11 are removed using photolithography and etching processes, and the surface of the exposed N-type GaN layer is determined as the N-type electrode region 1101 .

[0041] S14 Figure 13 As shown, using photolithography and metal deposition processes, a Ti / Al / Ni / Au metal stack is deposited on the surface of the N-type GaN layer described in S12 as the N-type electrode layer 1201, and a Ti / Al / Ni / Au metal stack is deposited on the surface of the ITO layer of the P-type electrode area 1001 described in S11 as the P-type electrode metal thickening layer 1202.

[0042] S15 cuts the nitride micro-resonant cavity light emitting diode structure prepared in S1 to S14 into chips, thereby forming nitride micro-resonant cavity light emitting diode chips.

[0043] The beneficial effects of the present invention are as follows: (1) The present invention discloses a method for preparing a nitride micro-resonant cavity light-emitting diode chip, which does not require a substrate peeling process and simplifies the preparation process of the nitride micro-resonant cavity light-emitting diode chip.

[0044] (2) The nitride micro-resonant cavity light-emitting diode chip prepared based on the present invention effectively shortens the cavity length of the resonant cavity, enhances the selectivity of emission of specific wavelengths, and improves the directionality and intensity of light output.

[0045] (3) The light-emitting pixels of the nitride micro-resonant cavity light-emitting diode chip prepared based on the present invention are located in the lateral closure area of ​​the selective area epitaxy, which helps to reduce the dislocation density of the light-emitting layer, thereby improving the luminous efficiency of the nitride micro-resonant cavity light-emitting diode device.

[0046] (4) Based on the preparation method of the nitride micro-resonant cavity light-emitting diode chip provided by the present invention, a nitride micro-resonant cavity light-emitting diode display array chip with high pixel density can be realized.

[0047] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0048] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for preparing a nitride micro-resonant cavity light-emitting diode chip, characterized in that: include: Providing a preset substrate, and sequentially preparing an N-type nitride layer and a first distributed Bragg reflector stack on the preset substrate; Etching the first distributed Bragg reflector stack into a periodic array to obtain a first distributed Bragg reflector array, so as to form a selective epitaxial window of the N-type nitride layer between units of the first distributed Bragg reflector array; performing selective epitaxy of the N-type nitride layer in the selective epitaxial window, controlling the N-type nitride layer in the selective epitaxial window to grow laterally toward the first distributed Bragg reflector array region by adjusting growth parameters, and achieving growth closure on units of the first distributed Bragg reflector array to obtain a first distributed Bragg reflector array buried layer structure; sequentially growing a light-emitting layer and a P-type nitride layer on the first distributed Bragg reflector array buried layer structure to obtain a nitride light-emitting diode epitaxial structure, defining a pixel area, and growing an arrayed metal layer on the surface of the pixel area; Using the metal layer as a mask, an ion implantation process is used to transform the P-type nitride layer in the spacer region of the array unit of the metal layer into an insulating region, and an acidic solution is used to remove the metal layer; Vapor-depositing a P-type transparent electrode layer on the surface of the nitride light-emitting diode epitaxial structure treated by the ion implantation process; preparing a second distributed Bragg reflector stack on the P-type transparent electrode layer in the pixel area, so that the second distributed Bragg reflector stack and the first distributed Bragg reflector array buried layer structure form a resonant cavity; defining a P-type electrode region, removing the P-type transparent electrode layer, the P-type nitride layer, and the light-emitting layer in areas other than the P-type electrode region and the pixel region, defining the exposed N-type nitride layer as the N-type electrode region, depositing an N-type electrode layer on the surface of the N-type electrode region, and depositing a metal thickening layer on the surface of the P-type electrode region, to obtain a nitride micro-resonant cavity light-emitting diode structure; The nitride micro-resonant cavity light-emitting diode structure is cut into chips to obtain nitride micro-resonant cavity light-emitting diode chips.

2. The method for preparing a nitride micro resonant cavity light emitting diode chip according to claim 1, characterized in that: The pixel region includes one or more units of the first distributed Bragg reflector array and spacing regions between the array units.

3. The method for preparing a nitride micro resonant cavity light emitting diode chip according to claim 1, characterized in that: The preset substrate is any one of a sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon substrate, a silicon carbide substrate, a gallium oxide substrate, a gallium nitride composite template, and an aluminum nitride composite template; the N-type nitride layer is a stack composed of one or more of InN, GaN, AlN, InGaN, and AlGaN of N-type conductivity; the first distributed Bragg reflector stack structure is a periodic arrangement of two dielectric materials with different refractive indices; the light-emitting layer is a periodic multi-quantum well structure composed of two or more of InN, GaN, AlN, InGaN, and AlGaN; the P-type nitride layer is a stack composed of one or more of InN, GaN, AlN, InGaN, and AlGaN of P-type conductivity; the second distributed Bragg reflector stack is a periodic arrangement of two dielectric materials with different refractive indices.

4. The method for preparing a nitride micro resonant cavity light emitting diode chip according to claim 1, characterized in that: The unit size of the first distributed Bragg reflector array unit ranges from 0.1 μm to 100 μm; the array unit spacing of the first distributed Bragg reflector array unit ranges from 0.1 μm to 100 μm; the thickness of the N-type nitride layer on the first distributed Bragg reflector array buried layer structure ranges from 0.01 μm to 10 μm.

5. The method for preparing a nitride micro resonant cavity light emitting diode chip according to claim 1, characterized in that: The reflectivity of the first distributed Bragg reflector stack structure to the target wavelength is higher than 90%; the reflectivity of the second distributed Bragg reflector stack to the target wavelength ranges from 50% to 90%.

6. The method for preparing a nitride micro resonant cavity light emitting diode chip according to claim 2, characterized in that: The array units of the metal layer and the units of the first distributed Bragg reflector array in the pixel area are distributed in the same manner.

7. The method for preparing a nitride micro resonant cavity light emitting diode chip according to claim 6, characterized in that: The P-type electrode region is distributed in a ring shape and surrounds the pixel region.

8. A nitride micro-resonant cavity light-emitting diode chip, characterized in that: The chip is prepared by the method for preparing a nitride micro resonant cavity light emitting diode chip according to any one of claims 1 to 7.

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