Dual-emission-direction micro-led structure and preparation method thereof

Abstract

The application discloses a double-emission-direction Micro-LED structure and a preparation method thereof. x Ga 1‑x N triangular island, a quantum well layer, a P-type layer, an electrode and other functional layers. The application utilizes selective epitaxy and combines lateral epitaxy to obtain an N-type In x Ga 1‑x N triangular island with high symmetry, and grows an LED epitaxial layer on two symmetrical inclined surfaces of the triangular island, so that the double-emission-direction Micro-LED structure is formed, and the double-emission-direction Micro-LED structure can be used as a basic display unit of near-eye naked-eye three-dimensional display. Meanwhile, the independent epitaxial LED structure is grown on the inclined surfaces of the triangular island, so that the adverse effects caused by etching damage of the quantum well and the P-type layer in the traditional micro-processing technology can be avoided, the edge effect of each light-emitting unit is effectively inhibited, and the light-emitting efficiency is improved. The light-emitting units are arranged on the basis of close packing, so that the area of the epitaxial wafer can be effectively utilized to the maximum extent, and economic benefits are maximized.

Description

Technical Field

[0001] This invention relates to a Micro-LED structure with dual emission directions and its fabrication method, belonging to the fields of semiconductor light-emitting devices and micro LED displays. Background Technology

[0002] Micro-LED display technology has broad application prospects due to its advantages such as low power consumption, long lifespan, and good color rendering, especially in high-definition display fields of various sizes and shapes, including large displays, consumer electronics, automotive displays, virtual reality (VR), augmented reality (AR), and wearable displays. Currently, mainstream glasses-free 3D technology uses specific algorithms to arrange images interactively, and then uses a parallax barrier placed between the display backlight and the liquid crystal panel to achieve a glasses-free 3D effect. However, this suffers from the problem of reduced brightness and screen resolution due to the parallax barrier blocking the backlight module. Furthermore, in the near-eye glasses-free 3D field, the screen resolution severely affects the image quality due to the distance between the device and the observer and the limitations of the light-emitting panel area. Researchers have developed various techniques to improve resolution, such as increasing pixel density through time multiplexing and using Micro-LEDs for small-area high-resolution displays. Among these, increasing the screen PPI through Micro-LEDs to achieve high-resolution near-eye 3D displays is a current hot research direction. Therefore, Micro-LED display technology has become one of the next-generation display technologies that international research institutions and companies are focusing on. However, achieving 3D full-color display is one of the main challenges facing Micro-LED display technology. This is mainly because, under current technological conditions, it is still difficult to achieve monolithic integration of red, green, and blue primary color Micro-LEDs.

[0003] Currently, high-efficiency solid-state visible light sources mainly consist of GaN-based blue-green LEDs and AlInGaP-based red LEDs. When the emission wavelength of AlInGaP-based materials is modulated from red to yellow light, its bandgap gradually transitions from a direct bandgap to an indirect bandgap, leading to a rapid decrease in efficiency. This physical property severely restricts its development and application as a short-wavelength light source. Furthermore, AlInGaP-based LEDs exhibit strong surface recombination, and etching damage during Micro-LED fabrication further exacerbates surface recombination, resulting in severe non-radiative recombination. Studies have shown that when the LED chip size is reduced to 262 μm, its external quantum efficiency is less than 6%; when the size is further reduced to 32 μm, the external quantum efficiency is less than 1%; and some reports even indicate that 50 × 50 μm... 2For chips of this size, the external quantum efficiency is less than 0.12%. This phenomenon severely restricts the application of AlInGaP-based LEDs as red light sources in the field of Micro-LED displays. The low luminous efficiency of long-wavelength InGaN-based LEDs is due to the difficulty in epitaxial growth of InGaN with high In content, but this problem can be solved through technological means, and some progress has been made. On the other hand, InGaN-based LEDs have relatively low nonradiative recombination due to etching damage, and their emission wavelength can cover the entire visible light band. Therefore, they are most promising for applications in Micro-LED displays and high-speed visible light communication, although their efficiency in the red light band is currently low. Therefore, solving the problems of epitaxial growth of InGaN thin films with high In content and nonradiative recombination due to etching damage has become an important research topic. Summary of the Invention

[0004] The main difficulty in applying Micro-LEDs in near-eye naked-eye 3D displays lies in the challenge of designing high-density Micro-LED matrix structures to achieve 3D visual effects. Furthermore, quantum well etching damage is easily generated during Micro-LED structure fabrication, leading to severe non-radiative recombination and reduced luminous efficiency. This invention provides a dual-emission Micro-LED structure that specifically addresses the etching damage problem during Micro-LED structure fabrication by designing a densely packed In... x Ga 1-x The N-triangular island structure further epitaxially grows independent Micro-LED structures, fundamentally avoiding etching damage to multiple quantum wells and improving the radiative recombination efficiency of nitride Micro-LEDs. The light-emitting units are arranged based on close packing, maximizing the utilization of the epitaxial wafer area. Simultaneously, the unique dual-emission Micro-LED structure emits light in two different directions during operation, allowing for further structural design to allow the light from each direction to enter the left and right eyes respectively, creating a parallax effect and achieving a 3D display effect. Furthermore, this structure facilitates the design of 3D display algorithms, thereby achieving delicate and realistic near-eye naked-eye 3D image display and maximizing economic benefits.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a Micro-LED structure with dual emission directions, comprising, from bottom to top, an N-type GaN layer 101 with an upward-facing non-polar crystal plane, a mask layer 102 containing a micropore array, and an N-type In layer with an In composition of 0 ≤ x ≤ 0.35. x Ga 1-x N-triangular island 103, strain control layer 104, quantum well layer 105, carrier control layer 106, P-type In with In composition y yGa 1-y N-layer 107, and P-type In y Ga 1-y The N-layer 107 has PL electrode 108 and PR electrode 109 with good ohmic contact, and N electrode 1010 with good ohmic contact with the N-type GaN layer 101.

[0007] The N-type In x Ga 1-x The N-shaped triangular island 103 is epitaxially grown upwards from the micropores of the mask layer 102, and includes two bilaterally symmetrical triangular bevels and one triangular side face perpendicular to the bottom, in addition to the bottom. The strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In... y Ga 1-y N-layer 107 and PL electrode 108 (or PR electrode 109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the inclined surface of N-triangular island 103, and the parameters of the same structure are exactly the same; on the left side are strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-y N-layer 107, PL electrode 108, N-electrode 1010 and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the right side contains the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In... y Ga 1-y N-layer 107, PR electrode 109, N-electrode 1010 and the N-type In on the right side x Ga 1-x The N-shaped triangular island slopes form the Micro-LED structure R. The N-electrode 1010 can be located at the top or bottom of the GaN layer 101, where the upward-facing crystal plane is non-polar, establishing a good ohmic contact. When the N-electrode 1010 is located at the top, it is positioned at In... x Ga 1-x N-triangle island, two oblique fronts, N-electrode 1010 and N-type In x Ga 1-x The N-triangular island 103 is non-contact; when the N-electrode 1010 is disposed at the bottom, the N-electrode covers the bottom of the entire N-type GaN layer 101 whose upward crystal plane is non-polar.

[0008] Preferably, the mask layer 102 containing the micropore array is formed by etching a micropore array from top to bottom on an N-type GaN layer 101 after a dielectric film of SiO2, SiN or hBN with a thickness of 5 to 50 nm is prepared on the N-type GaN layer 101. The micropores expose the underlying N-type GaN layer 101. The diameter of the micropores is between 0.5 and 5 μm, and they are arranged in a close-packed manner with the center of each micropore. The center of any micropore is equidistant from the center of the six adjacent micropores, and the distance can be adjusted according to actual needs.

[0009] Preferably, the GaN layer 101 with its upward crystal plane being nonpolar and the N-type In layer are... x Ga 1-x The upward-facing crystal plane of the N-triangular island 103 is simultaneously the (11-20) plane. At this point, the crystal planes of both the left and right bevels are simultaneously one of the {1-101} or {1-102} crystal plane families. Since the {1-101} or {1-102} crystal planes are lower potential energy planes, regular triangular islands can be formed, and the layer structure on top can grow regularly and controllably. Furthermore, the GaN layer 101 with its upward-facing crystal plane being a non-polar plane and the N-type In layer... x Ga 1-x The upward-facing crystal plane of the N-type triangular island 103 can also be (1-100) planes simultaneously, in which case the crystal planes of the two beveled surfaces on the left and right sides are simultaneously {20-21} crystal plane family; N-type In x Ga 1-x The sides of the N-triangular island 103 perpendicular to the bottom surface are all (000-1) planes. Using close-packing as the basis for arranging the light-emitting units maximizes the effective utilization of the epitaxial wafer area. The mesa structure fundamentally avoids the damage to the multiple quantum wells caused by etching, improving the radiative recombination efficiency of the nitride Micro-LED. Furthermore, the mesa structure helps release underlying stress, improving the crystal quality of the entire LED structure, thereby weakening the influence of defects and polarization on charge carriers and improving the LED's luminous efficiency. Simultaneously, the unique dual-emission Micro-LED structure emits light in two different directions during operation. Further structural designs allow the light from these two directions to enter the left and right eyes respectively, creating a parallax effect and achieving a 3D display effect. This structure also facilitates the design of 3D display algorithms, enabling detailed and realistic near-eye naked-eye 3D image display, maximizing economic benefits.

[0010] Preferably, when the micropore diameter of the mask layer 102 is no greater than 1.5 μm, N-type In x Ga 1-x The diameter of the circumscribed circle of the N-type triangular island 103 within the plane can be adjusted between 5 and 20 μm as needed. This is because when the micropores are small, regular islands are easily formed, and the size of the islands can be controlled as required. When the micropore diameter of the mask layer 102 is greater than 1.5 μm, the N-type In... x Ga 1-xThe diameter of the circumscribed circle of the N triangular island 103 in the plane is 3 to 4 times the diameter of the micropores, but not exceeding 15 μm at most. When the micropores are large, the islands are prone to irregularity, so the size of the islands is limited.

[0011] Preferably, the strain control layer 104 covers the entire N-type In x Ga 1-x both inclined planes of the N triangular island 103, but does not cover the N-type In x Ga 1-x at the edge of the middle of the N triangular island 103; when the N-type In x Ga 1-x When the molar fraction x of the N triangular island ≤ 0.05, the strain control layer 104 is a GaN / Al x1 Ga 1-x1 N / GaN composite layer from bottom to top for 1 to 3 cycles, where Al x1 Ga 1-x1 The thickness of N is less than 3 nm, x1 < 0.15, that is, when x is small, the stress of In x Ga 1-x N is small, and only a lower component of AlGaN needs to be introduced to compensate for a certain in-plane stress in the c direction; when the N-type In x Ga 1-x When the molar fraction 0.05 < x < 0.15 of the N triangular island, the strain control layer 104 is a GaN / Al x1 [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0012] Preferably, the two sets of quantum wells symmetrically cover the top of the strain control layer 104, have the same area and are not connected to each other, and their shape is consistent with the inclined surface of the GaN three-dimensional triangular island 103; when the quantum wells emit red, green and blue light respectively, the number of quantum well pairs is 1-2 pairs, 2-4 pairs and 3-5 pairs respectively; the layer structure of the quantum wells is In x2 Ga 1-x2 N / GaN / Al x3 Ga 1-x3 N / GaN, due to In x2 Ga 1-x2 The lattice mismatch between N and GaN in the c-direction is Δ3 = 0.09797 × x²; Al x3 Ga 1-x3 The lattice mismatch between N and GaN in the c-direction is Δ4 = -0.03915 × x3; by adjusting the molar composition x2 and x3, In x2 Ga 1-x2 N and Al x3 Ga 1-x3 The lattice mismatch value of N in the c-direction is equivalent to that of GaN, i.e., x3 = 2.5 × x2 ± 0.05, while controlling In... x2 Ga 1-x2 The thickness of N is 2-4 nm, consisting of two layers of GaN and Al. x3 Ga 1-x3 The total thickness of N does not exceed 6nm, thus better releasing stress, improving the radiative recombination efficiency of the quantum well, and improving optical efficiency.

[0013] Preferably, the carrier control layer 106 is either an electron blocking layer or a hole injection layer; wherein the electron blocking layer is an Al layer with 2 to 8 periods and a single period thickness of less than 8 nm. y1 Ga (1-y1) N / GaN superlattice, wherein the molar composition y1 is between 0.1 and 0.6, and is similar to Al y1 Ga (1-y1) The thickness of N is negatively correlated; the hole injection layer is an Al doped layer with an overall thickness of less than 30 nm. y2 Ga (1-y2) N / In y3 Ga (1-y3) N / GaN superlattice, with a Mg doping concentration of 5 × 10⁻⁶ 17 cm -3 ~1×10 19 cm -3 Between these values, the hole concentration is no higher than 1×10⁻⁶. 18 cm -3By setting an electron blocking layer with a wider bandgap or a highly p-doped hole injection layer, the carriers in the active region, i.e., the multiple quantum wells, can be confined, thereby increasing the overlap of the hole and electron wave functions in the multiple quantum wells and achieving higher radiative recombination efficiency.

[0014] Preferred, P-type In y Ga 1-y The thickness of the N-layer 107 is between 50 and 200 nm, and the molar composition y is between 0 and 0.15. When y = 0, it is GaN; the Mg element doping concentration is 2 × 10⁻⁶. 19 cm -3 ~5×10 19 cm -3 Between these points, the hole concentration is not less than 1×10 18 cm -3 ; among which P-type In y Ga 1-y Within a 5–30 nm thick region on the upper surface of the N-layer 107, the Mg doping concentration is not less than 1 × 10⁻⁶. 20 cm -3 Its hole concentration is not less than 5×10 18 cm -3 .

[0015] On the other hand, the present invention provides a method for fabricating the Micro-LED structure with dual emission directions.

[0016] The method for fabricating the dual-emission-direction Micro-LED structure can be used to fabricate a structure comprising, from bottom to top, an N-type GaN layer 101 with a non-polar upward crystal plane, a mask layer 102 containing a micropore array, and an N-type In with an In composition of 0 ≤ x ≤ 0.35. x Ga 1-x N-triangular island 103, strain control layer 104, quantum well layer 105, carrier control layer 106, P-type In with In composition y y Ga 1-y N-layer 107, and P-type In y Ga 1-y The N-layer 107 has PL electrodes 108 and PR electrodes 109 with good ohmic contact, and an N electrode 1010 with good ohmic contact to the N-type GaN layer 101. Among them, the N-type In... x Ga 1-x The N-shaped triangular island 103 is epitaxially grown upwards from the micropores of the mask layer 102 at its bottom, and includes two bilaterally symmetrical triangular bevels and one triangular side face perpendicular to the bottom, in addition to the bottom surface; furthermore, the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-yN-layer 107 and PL electrode 108 (or PR electrode 109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the inclined surface of N-triangular island 103, and the parameters of the same structure are exactly the same; on the left side are strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-y N-layer 107, PL electrode 108, N-electrode 1010 and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the strain control layer 104, quantum well layer 105, carrier control layer 106, P-type InyGa1-yN layer 107, PR electrode 109, and N electrode 1010 on the right side are connected to the N-type In on the right side. x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure R. The N-electrode 1010 is disposed on top of the N-type GaN layer 101, whose upward crystal plane is non-polar, located in In... x Ga 1-x N-triangle island, two oblique fronts, N-electrode 1010 and N-type In x Ga 1-x N-triangular island 103 is non-contact. The fabrication method of this Micro-LED structure includes the following steps:

[0017] a) Prepare a nonpolar N-type GaN template as an N-type GaN layer 101 with the upward crystal plane being nonpolar, or epitaxially grow an N-type GaN thin film with the upward crystal plane being nonpolar on a sapphire, Si, or SiC substrate as an N-type GaN layer.

[0018] GaN layer 101;

[0019] b) A non-metallic compound dielectric layer is prepared on the N-type GaN layer 101 with the upward crystal plane being non-polar. Micro-fabrication technology is used to process a micro-pore structure on the dielectric layer to form a mask layer 102 containing a micro-pore array, exposing the underlying N-type GaN layer 101.

[0020] c) Selective epitaxy is performed using the aforementioned micropores, followed by controlling the epitaxial growth temperature,

[0021] The V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rate enable lateral extension, forming an In composition of 0 ≤ x ≤

[0022] 0.35 N-type In x Ga 1-x N-Triangle Island 103;

[0023] d) In N-type In xGa 1-x Based on the N-type triangular island 103, a strain-controlled layer 104 is epitaxially grown, and combined with microfabrication technology, the strain-controlled layer 104 covers the entire N-type In. x Ga 1-x The N-shaped triangular island has two sloping surfaces on its left and right sides (103), but does not cover the N-type In. x Ga 1-

[0024] x The edge in the middle of N-triangle island 103;

[0025] e) Epitaxially grow a quantum well layer 105 on the strain control layer 104, so that the quantum wells symmetrically cover the top of the strain control layer 104.

[0026] f) Epitaxially grow a carrier control layer 106 on the quantum well layer 105 and cover the quantum well layer 105;

[0027] g) Epitaxial growth of P-type In on carrier control layer 106 y Ga 1-y N layers 107, and covering carrier control layer 106;

[0028] h) Using standard microfabrication techniques, etch the corresponding positions of the N electrode 1010 on the mask layer 102 to expose the underlying N-type GaN layer 101; select one of evaporation deposition and magnetron sputtering techniques to complete the PL electrode 108, PR electrode 109 and N electrode 1010, and complete the fabrication of this Micro-LED structure.

[0029] The method for fabricating the dual-emission-direction Micro-LED structure can be used to fabricate a structure comprising, from bottom to top, an N-type GaN layer 101 with a non-polar upward crystal plane, a mask layer 102 containing a micropore array, and an N-type In with an In composition of 0 ≤ x ≤ 0.35. x Ga 1-x N-triangular island 103, strain control layer 104, quantum well layer 105, carrier control layer 106, P-type In with In composition y y Ga 1-y N-layer 107, and P-type In y Ga 1-y The N-layer 107 has PL electrodes 108 and PR electrodes 109 with good ohmic contact, and an N electrode 1010 with good ohmic contact to the N-type GaN layer 101. Among them, the N-type In... x Ga 1-xThe N-shaped triangular island 103 is epitaxially grown upwards from the micropores of the mask layer 102 at its bottom, and includes two bilaterally symmetrical triangular bevels and one triangular side face perpendicular to the bottom, in addition to the bottom surface; furthermore, the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-y N-layer 107 and PL electrode 108 (or PR electrode 109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the inclined surface of N-triangular island 103, and the parameters of the same structure are exactly the same; on the left side are strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-y N-layer 107, PL electrode 108, N-electrode 1010 and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the right side contains the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In... y Ga 1-y N-layer 107, PR electrode 109, N-electrode 1010 and the N-type In on the right side x Ga 1-x The N-shaped triangular island slopes form the Micro-LED structure R. An N-electrode 1010 is disposed at the bottom of the GaN layer 101, whose upward crystal plane is non-polar, directly covering the entire bottom of the N-type GaN layer 101. The fabrication method of this Micro-LED structure includes the following steps:

[0030] a) Prepare a nonpolar N-type GaN template as an N-type GaN layer 101 with the upward crystal plane being nonpolar, or epitaxially grow an N-type GaN thin film with the upward crystal plane being nonpolar on a sapphire, Si, or SiC substrate as an N-type GaN layer.

[0031] GaN layer 101;

[0032] b) A non-metallic compound dielectric layer is prepared on the N-type GaN layer 101 with the upward crystal plane being non-polar. Micro-fabrication technology is used to process a micro-pore structure on the dielectric layer to form a mask layer 102 containing a micro-pore array, exposing the underlying N-type GaN layer 101.

[0033] c) Selective epitaxy is performed using the aforementioned micropores, followed by controlling the epitaxial growth temperature,

[0034] The V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rate enable lateral extension, forming an In composition of 0 ≤ x ≤

[0035] 0.35 N-type Inx Ga 1-x N-Triangle Island 103;

[0036] d) In N-type In x Ga 1-x Based on the N-type triangular island 103, a strain-controlled layer 104 is epitaxially grown, and combined with microfabrication technology, the strain-controlled layer 104 covers the entire N-type In. x Ga 1-x The N-shaped triangular island has two sloping surfaces on its left and right sides (103), but does not cover the N-type In. x Ga 1-

[0037] x The edge in the middle of N-triangle island 103;

[0038] e) Epitaxially grow a quantum well layer 105 on the strain control layer 104, so that the quantum wells symmetrically cover the top of the strain control layer 104.

[0039] f) Epitaxially grow a carrier control layer 106 on the quantum well layer 105 and cover the quantum well layer 105;

[0040] g) Epitaxial growth of P-type In on carrier control layer 106 y Ga 1-y N layers 107, and covering carrier control layer 106;

[0041] h) The PL electrode 108 and PR electrode 109 are prepared by using one of the following techniques: evaporation coating or magnetron sputtering.

[0042] i) The structure above the N-type GaN layer 101 is peeled off using a stripping process, and an N-electrode 1010 is prepared at the bottom of the original N-type GaN layer 101 using one of the following techniques: evaporation coating or magnetron sputtering, thus completing the fabrication of this Micro-LED structure.

[0043] Beneficial effects:

[0044] This invention proposes a Micro-LED structure with dual emission directions and its fabrication method. The design employs microvia selective area epitaxy (SIE) technology to grow N-type In with a low potential energy surface. x Ga 1-x N, naturally forming a highly symmetrical triangular island structure, thus achieving the regular and controllable growth of the island surface layer structure. In In x Ga 1-xThe fabrication of independent Micro-LED full structures on the N-shaped triangular island slope fundamentally avoids the damage to multiple quantum wells caused by etching, thereby improving the radiative recombination efficiency of nitride Micro-LEDs. Furthermore, the triangular island structure facilitates the release of stress between layers during epitaxial growth, improving the crystal quality of the fabricated Micro-LED full structure, mitigating the influence of defects and polarization on charge carriers, and ultimately enhancing the luminous efficiency of Micro-LEDs.

[0045] At the same time to alleviate In x Ga 1-x Due to the significant lattice mismatch between InGaN and AlGaN quantum wells, a series of adverse effects occur (such as defects caused by stress release). This invention addresses this by incorporating a strain control layer and a specially designed quantum well structure before quantum well growth. By introducing an AlGaN layer with a specific molar composition, a strain opposite to that of InGaN is generated to counteract the strain in InGaN. The principle is as follows: First, according to the formula...

[0046]

[0047] Calculate the lattice mismatch value, where Δ is the lattice mismatch value and c is the lattice mismatch value. GaN The c-axis lattice constant of GaN is 5.185 Å, and the c-axis lattice constant is... n Indicates Al x1 Ga 1-x1 N and In x Ga 1-x The c-axis lattice constant of N. n The calculation formula is:

[0048] c n =b×c AlN或InN +(1-b)c GaN

[0049] Where b is x, x1, x2, or x3, c AlN或InN Let be the c-axis lattice constants of AlN and InN, which are 4.982 Å and 5.693 Å, respectively. Substituting the corresponding values, we can obtain Al... x1 Ga 1-x1 The lattice mismatch between N and GaN in the c-direction is Δ1 = -0.03915 × x1; In x Ga 1-x The lattice mismatch between N and GaN in the c-direction is Δ2 = 0.09797 × x; In x2 Ga 1-x2 The lattice mismatch between N and GaN in the c-direction is Δ3 = 0.09797 × x²; Al x3 Ga 1-x3 The lattice mismatch between N and GaN in the c-direction is Δ4 = -0.03915 × x3. By adjusting the molar composition x, x1, x2, and x3, Al...x1 Ga 1-x1 N and In x Ga 1-x N has a lattice mismatch value comparable to that of GaN in the c-direction; In x2 Ga 1-x2 N and Al x3 Ga 1-x3 The lattice mismatch value of N in the c direction is equivalent to that of GaN (e.g., let Δ1 = -Δ2, Δ3 = -Δ4), that is, satisfying x1 = 2.5 × x ± 0.05, x3 = 2.5 × x2 ± 0.05. At this time, AlGaN will produce strain in the opposite direction and with a similar value to InGaN to counteract the strain of InGaN, suppress the defects generated by InGaN due to excessive strain, and thus obtain a high-quality quantum well and improve the overall luminous efficiency of Micro-LED.

[0050] By setting up an electron blocking layer with a wider bandgap or a hole injection layer with high P doping, the carriers in the active region, i.e., the multiple quantum wells, are confined. This increases the overlap of the wave functions of holes and electrons in the multiple quantum wells, resulting in higher radiative recombination efficiency. This further solves the problem that the internal quantum efficiency decreases with the increase of injection current density.

[0051] This invention utilizes a close-packed arrangement of light-emitting units to maximize the effective use of the epitaxial wafer area. The naturally formed, highly symmetrical dual-emission Micro-LED structure emits light in two different directions during operation. Further structural design allows the light from each direction to enter the left and right eyes respectively, creating a parallax effect and achieving a 3D display effect. This structure also facilitates the design of 3D display algorithms, offering significant advantages in near-eye naked-eye 3D display. Furthermore, leveraging the micron-level size of Micro-LEDs, a higher PPI can be achieved per unit area, easily producing detailed and realistic images with broad application scenarios. Attached Figure Description

[0052] Exemplary embodiments are illustrated in the accompanying drawings. The embodiments and drawings disclosed herein should be considered illustrative rather than restrictive.

[0053] Figure 1 This is a cross-sectional schematic diagram of a Micro-LED structure with dual emission directions, provided by the present invention, in which an N electrode is placed on top of an N-type GaN layer with an upward crystal plane that is non-polar.

[0054] Figure 2 This is a top view schematic diagram of a Micro-LED structure with dual emission directions, provided by the present invention, in which an N electrode is placed on top of an N-type GaN layer with an upward crystal plane that is non-polar.

[0055] Figure 3This is a cross-sectional schematic diagram of a Micro-LED structure with dual emission directions, provided by the present invention, in which an N electrode is placed at the bottom of an N-type GaN layer with an upward crystal plane that is non-polar.

[0056] Figure 4 This is a top view schematic diagram of a Micro-LED structure with dual emission directions when the N electrode is placed at the bottom of an N-type GaN layer with a non-polar crystal plane facing upwards, as provided by the present invention.

[0057] In the figure: 101 is an N-type GaN layer with a non-polar crystal plane facing upwards; 102 is a mask layer containing a micropore array; 103 is an N-type In layer. x Ga 1-x N-type triangular island, 104 is the strain control layer, 105 is the quantum well layer, 106 is the carrier control layer, and 107 is the p-type In layer. y Ga 1-y N-layer, 108 is the PL electrode, 109 is the PR electrode, and 1010 is the N electrode. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0060] Example 1:

[0061] The cross-sectional view of Example 1 is shown below. Figure 1 A top-down view is shown below. Figure 2 It includes, from bottom to top, an N-type GaN layer 101 with a non-polar crystal plane, a mask layer 102 containing a micropore array, and an N-type In layer. x Ga 1-x N-triangle island 103, strain control layer 104, quantum well layer 105, carrier control layer 106, P-type In y Ga 1-y N-layer 107, and P-type In y Ga 1-yThe N-layer 107 has PL electrodes 108 and PR electrodes 109 with good ohmic contact, and an N electrode 1010 with good ohmic contact to the N-type GaN layer 101. Among them, the N-type In... x Ga 1-x The N-shaped triangular island 103 is epitaxially grown upwards from the micropores of the mask layer 102 at its bottom, and includes two bilaterally symmetrical triangular bevels and one triangular side face perpendicular to the bottom, in addition to the bottom surface; furthermore, the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-y N-layer 107 and PL electrode 108 (or PR electrode 109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the inclined surface of N-triangular island 103, and the parameters of the same structure are exactly the same; on the left side are strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-y N-layer 107, PL electrode 108, N-electrode 1010 and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the right side contains the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In... y Ga 1-y N-layer 107, PR electrode 109, N-electrode 1010 and the N-type In on the right side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure R. The N-electrode 1010 is disposed on top of the N-type GaN layer 101, whose upward crystal plane is non-polar, located in In... x Ga 1- x N-triangle island, two oblique fronts, N-electrode 1010 and N-type In x Ga 1-x N-Triangle Island 103 is non-contact.

[0062] The specific parameters and preparation method for Example 1 are as follows:

[0063] An N-type GaN template with a non-polar upward crystal plane (11-20) is used as the N-type GaN layer 101. A 25 nm thick SiO2 layer is deposited on the N-type GaN layer 101 as a non-metallic compound dielectric layer. A micropore array is formed in the non-metallic compound dielectric layer, with the underlying N-type GaN layer 101 exposed in the micropores. The diameter of the micropores is 1.5 μm, and they are arranged in a close-packed manner with the center of each micropore. The distance between the center of any micropore and the center of the six adjacent micropores is 25 μm.

[0064] N-type In with an In composition of x = 0.05 is formed at the aforementioned micropore locations. x Ga 1-x N-Triangle Island 103; N-type In x Ga 1-x The outer circle diameter of the N-triangle island 103 in the plane is 15 μm, and the GaN layer 101 and N-type In are... x Ga 1-x The upward-facing crystal planes of the N-triangular island 103 are simultaneously (11-20) planes. At this point, the crystal planes of both the left and right inclined planes are simultaneously {1-101} crystal plane families, and the N-type In... x Ga 1-x The side of N-triangle island 103 that is perpendicular to the bottom surface is the (000-1) surface.

[0065] In N-type In x Ga 1-x Two cycles of bottom-up GaN / Al are arranged on the symmetrical inclined surface of the N-triangle island 103. x1 Ga 1-x1 N / GaN composite layer, in which Al x1 Ga 1-x1 The thickness of N is 2.5 nm, x1 = 0.1, and a lower composition AlGaN is introduced to compensate for a certain amount of in-plane stress in the c-direction, serving as a strain control layer 104. The strain control layer 104 covers the entire N-type In... x Ga 1-x The N-shaped triangular island has two sloping surfaces on its left and right sides (103), but does not cover the N-type In. x Ga 1-x The edge in the middle of the N-triangle island 103.

[0066] Two sets of quantum wells, one on the left and one on the right, are symmetrically positioned on top of the strain control layer 104. These sets have the same area and are not connected to each other. Their shape corresponds to the inclined surface of the GaN three-dimensional triangular island 103. When the quantum wells emit red, green, and blue light, the number of quantum well pairs is 2, 3, and 4, respectively. The layer structure of the quantum wells is In... x2 Ga 1-x2 N / GaN / Al x3 Ga 1-x3 N / GaN, where x2 = 0.2, x3 = 0.5 and In x2 Ga 1-x2 The thickness of N is 3nm, consisting of two layers of GaN and Al. x3 Ga 1-x3 The total thickness of N is 5 nm.

[0067] A six-period Al layer with a thickness of 8 nm per period was set on the quantum well layer 105. y1 Ga (1-y1) The N / GaN superlattice, with a molar composition y1 of 0.4, serves as the carrier control layer.

[0068] A 100 nm thick P-type In layer with a molar composition y of 0.1 was fabricated on the carrier control layer. y Ga 1-y N-layer 107; Mg doping concentration adjusted to 3×10⁻⁷ 19 cm -3 Its hole concentration is 1.5 × 10⁻⁶. 18 cm -3 ; among which P-type In y Ga 1-y Within a 20 nm thick region on the upper surface of the N-layer 107, the Mg doping concentration is 1.5 × 10⁻⁶. 20 cm -3 Its hole concentration is 5×10 18 cm -3 .

[0069] The specific preparation process for this example structure is as follows:

[0070] a) Prepare an N-type GaN template with one crystallographic plane being a non-polar plane (11-20) as the N-type GaN layer 101;

[0071] b) A non-metallic compound dielectric layer is prepared on the N-type GaN layer 101. Microfabrication technology is used to fabricate a microporous structure on the dielectric layer to form a mask layer 102 containing a microporous array, exposing the underlying N-type GaN layer 101.

[0072] c) Selective epitaxy is performed using the aforementioned micropores, followed by controlling the epitaxial growth temperature,

[0073] The V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rate enable lateral extension, forming an In composition with x = 0.05.

[0074] N-type In x Ga 1-x N-Triangle Island 103;

[0075] d) In N-type In x Ga 1-x Based on the N-type triangular island 103, a strain-controlled layer 104 is epitaxially grown, and combined with microfabrication technology, the strain-controlled layer 104 covers the entire N-type In. x Ga 1-x The N-shaped triangular island has two sloping surfaces on its left and right sides (103), but does not cover the N-type In. x Ga 1-

[0076] x The edge in the middle of N-triangle island 103;

[0077] e) Epitaxially grow a quantum well layer 105 on the strain control layer 104, so that the quantum wells symmetrically cover the top of the strain control layer 104.

[0078] f) Epitaxially grow a carrier control layer 106 on the quantum well layer 105 and cover the quantum well layer 105;

[0079] g) Epitaxial growth of P-type In on carrier control layer 106 y Ga 1-y N layers 107, and covering carrier control layer 106;

[0080] h) Using standard microfabrication techniques, etch the corresponding positions of the N electrode 1010 on the mask layer 102 to expose the underlying N-type GaN layer 101; select one of evaporation deposition and magnetron sputtering techniques to complete the PL electrode 108, PR electrode 109 and N electrode 1010, and complete the fabrication of this Micro-LED structure.

[0081] Example 2:

[0082] The cross-sectional view of Example 2 is shown below. Figure 3 A top-down view is shown below. Figure 4 It includes, from bottom to top, an N-type GaN layer 101 with a non-polar crystal plane, a mask layer 102 containing a micropore array, and an N-type In layer. x Ga 1-x N-triangular island 103, strain control layer 104, quantum well layer 105, carrier control layer 106, P-type In with In composition y y Ga 1-y N-layer 107, and P-type In y Ga 1- y The N-layer 107 has PL electrodes 108 and PR electrodes 109 with good ohmic contact, and an N electrode 1010 with good ohmic contact to the N-type GaN layer 101. Among them, the N-type In... x Ga 1-x The N-shaped triangular island 103 is epitaxially grown upwards from the micropores of the mask layer 102 at its bottom, and includes two bilaterally symmetrical triangular bevels and one triangular side face perpendicular to the bottom, in addition to the bottom surface; furthermore, the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga 1-y N-layer 107 and PL electrode 108 (or PR electrode 109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the inclined surface of N-triangular island 103, and the parameters of the same structure are exactly the same; on the left side are strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In y Ga1-y N-layer 107, PL electrode 108, N-electrode 1010 and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the right side contains the strain control layer 104, quantum well layer 105, carrier control layer 106, and P-type In... y Ga 1-y N-layer 107, PR electrode 109, N-electrode 1010 and the N-type In on the right side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure R. The N-electrode 1010 is disposed at the bottom of the GaN layer 101, whose upward crystal plane is non-polar, and directly covers the bottom of the entire N-type GaN layer 101.

[0083] The specific parameters and preparation method for Example 2 are as follows:

[0084] An N-type GaN thin film with a non-polar upward crystal plane (11-20) grown on a sapphire substrate is used as the N-type GaN layer 101. A 15 nm thick hBN layer is disposed on the N-type GaN layer 101 as a non-metallic compound dielectric layer; a micropore array is disposed in the non-metallic compound dielectric layer, with the underlying N-type GaN layer 101 exposed in the micropores; wherein the diameter of the micropores is 2 μm, and they are arranged in a close-packed manner with the center of the micropores as the center, and the distance between the center of any micropore and the center of the six adjacent micropores is 20 μm.

[0085] An N-type In with an In composition of x = 0.15 is formed at the center of the aforementioned micropores. x Ga 1-x N-Triangle Island 103; N-type In x Ga 1- x The N-triangle island 103 has a circumscribed circle diameter of 10 μm within its surface, and consists of a non-polar GaN layer 101 and an N-type In layer. x Ga 1-x The upward-facing crystal plane of the N-triangular island 103 is simultaneously the (11-20) plane. At this time, the crystal planes of the two beveled surfaces on the left and right are simultaneously the {1-102} family of crystal planes, and the N-type In... x Ga 1-x The sides of N-triangle island 103 that are perpendicular to the bottom are all (000-1) surfaces.

[0086] In N-type In x Ga 1-x Three cycles of bottom-up GaN / Al are arranged on the symmetrical inclined surface of the N-triangle island 103. x1 Ga 1-x1 N / GaN / In x Ga 1-x N composite layer, in which In xGa 1-x The molar composition x of N is N-type In x Ga 1-x The molar composition of the N-triangular island, Al x1 Ga 1-x1 The N layer, with a thickness of 1.5 nm, x = 0.16, and x1 = 0.4, serves as the strain control layer 104. The strain control layer 104 covers the entire N-type In layer. x Ga 1-x The N-shaped triangular island has two sloping surfaces on its left and right sides (103), but does not cover the N-type In. x Ga 1-x The edge in the middle of the N-triangle island 103.

[0087] Two sets of quantum wells, one on the left and one on the right, are symmetrically positioned on top of the strain control layer 104. These sets have the same area and are not connected to each other. Their shape corresponds to the inclined surface of the GaN three-dimensional triangular island 103. When the quantum wells emit red, green, and blue light, the number of quantum well pairs is 1, 4, and 3, respectively. The layer structure of the quantum wells is In... x2 Ga 1-x2 N / GaN / Al x3 Ga 1-x3 N / GaN, where x2 = 0.18, x3 = 0.45 and In x2 Ga 1-x2 The thickness of N is 2nm, consisting of two layers of GaN and Al. x3 Ga 1-x3 The total thickness of N does not exceed 6 nm.

[0088] An Al layer with a thickness of 25 nm is disposed on the quantum well layer 105. y2 Ga (1-y2) N / In y3 Ga (1-y3) The N / GaN superlattice is doped to achieve a Mg doping concentration of 5 × 10⁻⁶. 18 cm -3 Its hole concentration is 7×10 17 cm -3 It acts as a carrier control layer.

[0089] P-doped Al with an overall thickness of less than 30 nm was set on the carrier modulation layer. y2 Ga (1-y2) N / In y3 Ga (1-y3) N / GaN superlattice, with the Mg doping concentration of the carrier control layer controlled at 6 × 10⁻⁶. 18 cm -3 Its hole concentration is 1×10 18 cm -3 It acts as a carrier control layer.

[0090] A p-type In layer with a thickness of 90 nm and a molar composition y of 0.08 was deposited on the carrier control layer. y Ga 1-y N-layer 107; Mg doping concentration adjusted to 3×10⁻⁷ 19 cm -3 Its hole concentration is 2×10 18 cm -3 ; among which P-type In y Ga 1-y Within a 25nm thick region on the upper surface of the N-layer 107, the Mg doping concentration is 2×10⁻⁶. 20 cm -3 Its hole concentration is 6×10 18 cm -3 .

[0091] The specific preparation process for this example structure is as follows:

[0092] a) An N-type GaN thin film with a non-polar upward crystal plane (11-20) is epitaxially grown on a sapphire substrate as N-type GaN layer 101;

[0093] b) A non-metallic compound dielectric layer is prepared on the N-type GaN layer 101. Microfabrication technology is used to fabricate a microporous structure on the dielectric layer to form a mask layer 102 containing a microporous array, exposing the underlying N-type GaN layer 101.

[0094] c) Selective epitaxy is performed using the aforementioned micropores, followed by controlling the epitaxial growth temperature,

[0095] The V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rate enable lateral epitaxy to form an In component of...

[0096] N-type In with x = 0.15 x Ga 1-x N-Triangle Island 103;

[0097] d) In N-type In x Ga 1-x Based on the N-type triangular island 103, a strain-controlled layer 104 is epitaxially grown, and combined with microfabrication technology, the strain-controlled layer 104 covers the entire N-type In. x Ga 1-x The N-shaped triangular island has two sloping surfaces on its left and right sides (103), but does not cover the N-type In. x Ga 1-x The edge in the middle of N-triangle island 103;

[0098] e) Epitaxially grow a quantum well layer 105 on the strain control layer 104, so that the quantum wells symmetrically cover the top of the strain control layer 104.

[0099] f) Epitaxially grow a carrier control layer 106 on the quantum well layer 105 and cover the quantum well layer 105;

[0100] g) Epitaxial growth of P-type In on carrier control layer 106 y Ga 1-y N layers 107, and covering carrier control layer 106;

[0101] h) The PL electrode 108 and PR electrode 109 are prepared by using one of the following techniques: evaporation coating or magnetron sputtering.

[0102] i) The structure above the N-type GaN layer 101 is peeled off using a stripping process, and an N-electrode 1010 is prepared at the bottom of the original N-type GaN layer 101 using one of the following techniques: evaporation coating or magnetron sputtering, thus completing the fabrication of this Micro-LED structure.

[0103] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A Micro-LED structure with dual emission directions, characterized in that: Including an N-type GaN layer (101) with a non-polar surface as the upward crystal plane arranged from bottom to top, a mask layer (102) containing a microporous array, an N-type In with an In composition of 0 ≤ x ≤ 0.35 x Ga 1-x N triangular islands (103), a strain control layer (104), a quantum well layer (105), a carrier control layer (106), a P-type In with an In composition of y y Ga 1-y N layer (107), a PL electrode (108) and a PR electrode (109) having a good ohmic contact with the P-type In y Ga 1-y N layer (107), an N electrode (1010) having a good ohmic contact with the N-type GaN layer (101); wherein, the bottom of the N-type In x Ga 1-x N triangular islands (103) is epitaxially grown upward from the micropores of the mask layer (102), and except for the bottom, it includes two symmetric triangular inclined planes and a triangular side perpendicular to the bottom surface; the strain control layer (104) covers the left and right inclined planes of the entire N-type In x Ga 1-x N triangular islands (103), but does not cover the middle edge of the N-type In x Ga 1-x N triangular islands (103); when the molar composition x of the N-type In x Ga 1-x N triangular islands is x ≤ 0.05, the strain control layer (104) is a 1 - 3 period GaN / Al x1 Ga 1-x1 N / GaN composite layer, where the thickness of Al x1 Ga 1-x1 N is less than 3 nm, x1 < 0.15; when the molar composition of the N-type In x Ga 1-x N triangular islands is 0.05 < x < 0.15, the strain control layer (104) is a 1 - 3 period GaN / Al x1 Ga 1-x1 N / GaN / In x Ga 1-x N composite layer, where the molar composition of In x Ga 1-x N is x, which is the molar composition of the N-type In x Ga 1-x N triangular islands, the thickness of Al x1 Ga 1-x1 N is less than 2 nm, x1 = 2.5×x ± 0.05; the strain control layer (104), the quantum well layer (105), the carrier control layer (106), the P-type In y Ga 1- y The N-layer (107), PL electrode (108), or PR electrode (109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the slope of the N-triangle island (103), and the parameters of the same structure are exactly the same; the strain control layer (104), quantum well layer (105), carrier control layer (106), and P-type In on the left side. y Ga 1-y N-layer (107), PL electrode (108), N-electrode (1010) and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the right side consists of a strain control layer (104), a quantum well layer (105), a carrier control layer (106), and a P-type In... y Ga 1-y N-layer (107), PR electrode (109), N-electrode (1010) and the N-type In on the right side x Ga 1-x The N-shaped triangular island slopes form the Micro-LED structure R; the left and right sets of quantum wells symmetrically cover the top of the strain control layer (104), with the same area and not connected to each other, and their shape is similar to that of the N-type In x Ga 1-x The N-triangle island (103) has a uniform slope; when the quantum well emits red, green, and blue light respectively, the number of quantum well pairs is 1~2 pairs, 2~4 pairs, and 3~5 pairs respectively; the layer structure of the quantum well is In x2 Ga 1-x2 N / GaN / Al x3 Ga 1-x3 N / GaN, where x3 = 2.5 × x2 ± 0.05, and In x2 Ga 1-x2 The thickness of N is 2~4 nm, consisting of two layers of GaN and Al. x3 Ga 1-x3 The total thickness of N does not exceed 6 nm; the carrier control layer (106) is either an electron blocking layer or a hole injection layer; wherein the electron blocking layer is an Al with 2 to 8 periods and a single period thickness of less than 8 nm. y1 Ga (1-y1) N / GaN superlattice, wherein the molar composition y1 is between 0.1 and 0.6 and Al y1 Ga (1-y1) The thickness of N is negatively correlated; the hole injection layer is an Al doped layer with an overall thickness of less than 30 nm. y2 Ga (1-y2) N / In y3 Ga (1-y3) N / GaN superlattice, with a Mg doping concentration of 5 × 10⁻⁶ 17 cm -3 ~1×10 19 cm -3 Between these values, the hole concentration is no higher than 1×10⁻⁶. 18 cm -3 The N electrode (1010) is located at the top or bottom of the GaN layer (101) with the upward crystal plane being non-polar, respectively, and establishes a good ohmic contact; when the N electrode (1010) is located at the top, it is located in In x Ga 1-x In front of the two oblique faces of the N-triangle island, the N electrode (1010) and the N-type In x Ga 1-x The N-triangle island (103) is non-contact; when the N electrode (1010) is placed at the bottom, the N electrode covers the bottom of the entire N-type GaN layer (101) with the upward crystal plane being non-polar.

2. A Micro-LED structure with dual emission directions as described in claim 1, characterized in that: The mask layer (102) containing the micropore array is formed by etching a micropore array from top to bottom on an N-type GaN layer (101) after a dielectric film of SiO2, SiN or hBN with a thickness of 5 to 50 nm is prepared on the N-type GaN layer (101). The micropores expose the underlying N-type GaN layer (101). The diameter of the micropores is between 0.5 and 5 μm, and they are arranged in a close-packed manner with the center of the micropores. The center of any micropore is equidistant from the center of the six adjacent micropores, and the distance can be adjusted according to actual needs.

3. A Micro-LED structure with dual emission directions as described in claim 1, characterized in that: N-type GaN layer (101) and N-type In layer with nonpolar crystal planes facing upwards. x Ga 1-x The upward-facing crystal plane of the N-type triangular island (103) is simultaneously the (11-20) plane, and at this time, the crystal planes of the two beveled surfaces on the left and right are simultaneously one of the {1-101} or {1-102} crystal plane families; in addition, the N-type GaN layer (101) and the N-type In x Ga 1-x The upward-facing crystal plane of the N-triangular island (103) can also be the (1-100) plane simultaneously, in which case the crystal planes of the two beveled faces on the left and right sides are simultaneously the {20-21} family of crystal planes; N-type In x Ga 1-x The side of the N-type triangular island (103) perpendicular to the bottom surface is the (000-1) surface; when the micropore diameter of the mask layer (102) is no greater than 1.5 μm, the N-type In x Ga 1-x The diameter of the circumscribed circle of the N-type triangular island (103) in the plane is between 5 and 20 μm, which can be adjusted as needed; when the micropore diameter of the mask layer (102) is greater than 1.5 μm, the N-type In x Ga 1-x The diameter of the circumscribed circle of the N-triangle island (103) in the plane is 3 to 4 times the diameter of the micropore, but the maximum does not exceed 15 μm.

4. A Micro-LED structure with dual emission directions as described in claim 1, characterized in that: P-type In y Ga 1-y The thickness of the N-layer (107) is between 50 and 200 nm, and the molar composition y is between 0 and 0.

15. When y=0, it is GaN; the Mg element doping concentration is 2×10⁻⁶. 19 cm -3 ~5×10 19 cm -3 Between these points, the hole concentration is not less than 1×10 18 cm -3 ; among which P-type In y Ga 1-y Within a 5–30 nm thick region on the upper surface of the N-layer (107), the Mg doping concentration is not less than 1 × 10⁻⁶. 20 cm -3 Its hole concentration is not less than 5×10 18 cm -3 .

5. A method for fabricating a Micro-LED structure with dual emission directions, characterized in that: The micro-LED structure includes, from bottom to top, an N-type GaN layer (101) with a non-polar crystal plane, a mask layer (102) containing a micropore array, and an N-type In alloy with an In composition of 0 ≤ x ≤ 0.

35. x Ga 1-x N-triangular island (103), strain control layer (104), quantum well layer (105), carrier control layer (106), P-type In with In composition y y Ga 1-y N-layer (107), and P-type In y Ga 1-y The N-layer (107) has a PL electrode (108) and a PR electrode (109) with good ohmic contact, and an N electrode (1010) with good ohmic contact with the N-type GaN layer (101); wherein, the N-type In x Ga 1-x The N-shaped triangular island (103) is epitaxially grown from the micropores of the mask layer (102) at its bottom, and includes two bilaterally symmetrical triangular bevels and a triangular side face perpendicular to the bottom surface, in addition to the bottom surface; moreover, the strain control layer (104), quantum well layer (105), carrier control layer (106), and P-type In y Ga 1-y The N-layer (107), PL electrode (108), or PR electrode (109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the slope of the N-triangle island (103), and the parameters of the same structure are exactly the same; the strain control layer (104), quantum well layer (105), carrier control layer (106), and P-type In on the left side. y Ga 1-y N-layer (107), PL electrode (108), N-electrode (1010) and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the right side consists of a strain control layer (104), a quantum well layer (105), a carrier control layer (106), and a P-type In... y Ga 1-y N-layer (107), PR electrode (109), N-electrode (1010) and the N-type In on the right side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure R; the N electrode (1010) is disposed on top of the N-type GaN layer (101) with the upward crystal plane being non-polar, located in In x Ga 1-x In front of the two oblique faces of the N-triangle island, the N electrode (1010) and the N-type In x Ga 1-x N-triangle island (103) is non-contact; The fabrication method of this Micro-LED structure includes the following steps: a) Prepare a non-polar N-type GaN template as an N-type GaN layer (101) with the upward crystal plane being non-polar, or epitaxially grow an N-type GaN thin film with the upward crystal plane being non-polar on a sapphire, Si or SiC substrate as an N-type GaN layer (101). b) A non-metallic compound dielectric layer is prepared on the N-type GaN layer (101) with the upward crystal plane being non-polar. Micro-fabrication technology is used to process a micro-pore structure on the dielectric layer to form a mask layer (102) containing a micro-pore array, exposing the underlying N-type GaN layer (101). c) Selective area epitaxy (SIE) is performed using the aforementioned micropores. Lateral epitaxy is then achieved by controlling the epitaxial growth temperature, V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rate to form N-type In with an In composition of 0 ≤ x ≤ 0.

35. x Ga 1-x N-Triangle Island (103); d) In N-type In x Ga 1-x A strain-controlled layer (104) is epitaxially grown on the basis of the N-type triangular island (103), and combined with microfabrication technology, the strain-controlled layer (104) covers the entire N-type In. x Ga 1-x The N-shaped triangular island (103) has two sloping sides on the left and right, but does not cover the N-type In. x Ga 1-x The edge in the middle of the N-triangle island (103); e) Epitaxially grow a quantum well layer (105) on the strain control layer (104) so ​​that the quantum well symmetrically covers the top of the strain control layer (104); f) Epitaxially grow a carrier control layer (106) on the quantum well layer (105) and cover it with the quantum well layer (105); g) Epitaxial growth of P-type In on the carrier control layer (106) y Ga 1-y N layers (107) are covered with a carrier control layer (106); h) Using standard microfabrication techniques, the corresponding positions of the N electrode (1010) on the mask layer (102) are etched to expose the underlying N-type GaN layer (101); the PL electrode (108), PR electrode (109) and N electrode (1010) are completed by selecting one of the evaporation coating and magnetron sputtering techniques to complete the fabrication of this Micro-LED structure.

6. A method for fabricating a Micro-LED structure with dual emission directions, characterized in that: The micro-LED structure includes, from bottom to top, an N-type GaN layer (101) with a non-polar crystal plane, a mask layer (102) containing a micropore array, and an N-type In alloy with an In composition of 0 ≤ x ≤ 0.

35. x Ga 1-x N-triangular island (103), strain control layer (104), quantum well layer (105), carrier control layer (106), P-type In with In composition y y Ga 1-y N-layer (107), and P-type In y Ga 1-y The N-layer (107) has a PL electrode (108) and a PR electrode (109) with good ohmic contact, and an N electrode (1010) with good ohmic contact with the N-type GaN layer (101); wherein, the N-type In x Ga 1-x The N-shaped triangular island (103) is epitaxially grown from the micropores of the mask layer (102) at its bottom, and includes two bilaterally symmetrical triangular bevels and a triangular side face perpendicular to the bottom surface, in addition to the bottom surface; moreover, the strain control layer (104), quantum well layer (105), carrier control layer (106), and P-type In y Ga 1-y The N-layer (107), PL electrode (108), or PR electrode (109) are symmetrically arranged on the N-type In layer. x Ga 1-x On the slope of the N-triangle island (103), and the parameters of the same structure are exactly the same; the strain control layer (104), quantum well layer (105), carrier control layer (106), and P-type In on the left side. y Ga 1-y N-layer (107), PL electrode (108), N-electrode (1010) and the N-type In on the left side x Ga 1-x The N-shaped triangular island slope forms the Micro-LED structure L; the right side consists of a strain control layer (104), a quantum well layer (105), a carrier control layer (106), and a P-type In... y Ga 1-y N-layer (107), PR electrode (109), N-electrode (1010) and the N-type In on the right side x Ga 1-x The N-triangular island slope forms the Micro-LED structure R; the N electrode (1010) is set at the bottom of the GaN layer (101) with the upward crystal plane being non-polar, directly covering the bottom of the entire N-type GaN layer (101); The fabrication method of this Micro-LED structure includes the following steps: a) Prepare a non-polar N-type GaN template as an N-type GaN layer (101) with the upward crystal plane being non-polar, or epitaxially grow an N-type GaN thin film with the upward crystal plane being non-polar on a sapphire, Si or SiC substrate as an N-type GaN layer (101). b) A non-metallic compound dielectric layer is prepared on the N-type GaN layer (101) with the upward crystal plane being non-polar. Micro-fabrication technology is used to process a micro-pore structure on the dielectric layer to form a mask layer (102) containing a micro-pore array, exposing the underlying N-type GaN layer (101). c) Selective area epitaxy (SIE) is performed using the aforementioned micropores. Lateral epitaxy is then achieved by controlling the epitaxial growth temperature, V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rate to form N-type In with an In composition of 0 ≤ x ≤ 0.

35. x Ga 1-x N-Triangle Island (103); d) In N-type In x Ga 1-x A strain-controlled layer (104) is epitaxially grown on the basis of the N-type triangular island (103), and combined with microfabrication technology, the strain-controlled layer (104) covers the entire N-type In. x Ga 1-x The N-shaped triangular island (103) has two sloping sides on the left and right, but does not cover the N-type In. x Ga 1-x The edge in the middle of the N-triangle island (103); e) Epitaxially grow a quantum well layer (105) on the strain control layer (104) so ​​that the quantum well symmetrically covers the top of the strain control layer (104); f) Epitaxially grow a carrier control layer (106) on the quantum well layer (105) and cover it with the quantum well layer (105); g) Epitaxial growth of P-type In on the carrier control layer (106) y Ga 1-y N layers (107) are constructed, and a carrier control layer (106) is also constructed over them. h) The PL electrode (108) and PR electrode (109) are prepared by selecting one of the following techniques: evaporation coating or magnetron sputtering; i) The structure above the N-type GaN layer (101) is peeled off using a stripping process, and an N-electrode (1010) is prepared on the original bottom of the N-type GaN layer (101) using one of the following techniques: evaporation coating or magnetron sputtering, to complete the fabrication of this Micro-LED structure.

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