Micro light emitting diode chip and method of forming the same

Abstract

A micro light emitting diode chip and a method for forming the same, wherein the micro light emitting diode chip comprises: a first epitaxial layer having opposite first and second sides; a second epitaxial layer located at the second side; a multi-quantum well layer located between the first and second epitaxial layers; and a photonic crystal structure for optimizing light emission parameters, the photonic crystal structure being located at least on one side of the first epitaxial layer. The photonic crystal structure is a medium with periodic refractive index variation, and the propagation behavior of light can be affected by increasing the photonic crystal structure. According to the different depths and topographies of the medium holes, the photonic crystal structure can be used as a diffraction grating to control the light emission angle and wavelength, and also as an anti-reflection grating, thereby increasing the small-angle light emission to improve the light emission amount. Moreover, the photonic crystal structure can also regulate the photonic band gap by regulating the lattice parameters, topography, size or material, etc., so as to optimize the light emission efficiency.

Description

Technical Field

[0001] This invention relates to the field of microdisplay technology, and more particularly to a micro light-emitting diode chip and a method for forming the same. Background Technology

[0002] Inorganic micro-pixel light-emitting diodes, also known as micro LEDs or μ-LEDs, are a high-pixel-density LED planar display technology that uses micrometer-scale LEDs as pixels, assembled on a CMOS backplane at micrometer-scale intervals. The display principle involves thinning, miniaturizing, and arraying the LED structure, reducing its size to only a few to tens of micrometers. These micro-LED chips are then mass-produced and transferred onto a TFT or CMOS backplane. Micro LED displays possess excellent characteristics such as high light extraction efficiency, high brightness, short response time, and high reliability, and are hailed by the industry as the next-generation display technology and the ultimate form of display.

[0003] However, existing miniature light-emitting diode chips still have many problems. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a miniature light-emitting diode chip and a method for forming the same, thereby optimizing light extraction efficiency and increasing light output.

[0005] To address the aforementioned problems, the present invention provides a micro light-emitting diode chip, comprising: a first epitaxial layer having a first doped ion, the first epitaxial layer having a first side and a second side opposite to each other; a second epitaxial layer located on the second side, having a second doped ion, the second doped ion having a different electrical type than the first doped ion; a multi-quantum well layer located between the first epitaxial layer and the second epitaxial layer; and a photonic crystal structure used to optimize light emission parameters, the photonic crystal structure being located at least on one side of the first epitaxial layer.

[0006] Optionally, the photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side.

[0007] Optionally, the photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the second side.

[0008] Optionally, the photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side and the second side.

[0009] Optionally, it further includes: a conductive layer located on the first side, the conductive layer having a plurality of dielectric holes, the dielectric holes having a second dielectric body; a first dielectric body between adjacent dielectric holes; and the photonic crystal structure being composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

[0010] Optionally, it further includes: a second insulating layer located on the first side, the second insulating layer having a plurality of dielectric holes, the dielectric holes having a second dielectric body; a first dielectric body between adjacent dielectric holes; and the photonic crystal structure being composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

[0011] Optionally, the second epitaxial layer has a plurality of dielectric holes, and the dielectric holes contain a second dielectric body; a first dielectric body is located between adjacent dielectric holes; the photonic crystal structure is composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

[0012] Optionally, it further includes: a first insulating layer located on the second side, the first insulating layer having a plurality of dielectric holes, the dielectric holes having a second dielectric body; the first dielectric body being between adjacent dielectric holes; the photonic crystal structure being composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

[0013] Optionally, the second dielectric material includes: a transparent insulating material; the transparent insulating material includes: SiO2, SiN x One or more of the following: SiON, TiO2, Al2O3, and air.

[0014] Optionally, the morphological structure of the second medium includes one or more of the following: a pyramid, a cylinder, a square prism, a hexagonal prism, and a hemisphere.

[0015] Optionally, the morphological structure of the first medium includes one or more of the following: a pyramid, a cylinder, a square prism, a hexagonal prism, and a hemisphere.

[0016] Optionally, the second medium and the first medium may differ in one or more of their materials, morphology, and dimensions.

[0017] Optionally, the first epitaxial layer has a plurality of first epitaxial grooves; the second epitaxial layer has a plurality of second epitaxial grooves; the plurality of first epitaxial grooves and the plurality of second epitaxial grooves correspond to each other along the stacking direction of the first epitaxial layer and the second epitaxial layer.

[0018] Optionally, it also includes a pixel isolation layer located on the sidewall and bottom surface of the first epitaxial groove.

[0019] Optionally, the material of the pixel isolation layer includes: a transparent insulating material.

[0020] Optional transparent insulating materials include: SiO2, SiN x One or more of the following: SiON, TiO2, Al2O3, and air.

[0021] Optionally, it further includes: an epitaxial electrode layer located within the first epitaxial groove, the epitaxial electrode layer being electrically connected to the first epitaxial layer.

[0022] Optionally, the sidewall of the epitaxial electrode layer is an inclined surface, and the projection area of ​​the surface of the epitaxial electrode layer away from the first epitaxial layer toward the first epitaxial layer is located within the projection area of ​​the surface of the epitaxial electrode layer close to the first epitaxial layer toward the first epitaxial layer.

[0023] Optionally, the height of the epitaxial electrode layer is greater than the depth of the first epitaxial groove.

[0024] Optionally, it may also include a metal reflective layer located within the second epitaxial groove.

[0025] Accordingly, the present invention also provides a method for forming a micro light-emitting diode chip, comprising: forming a first epitaxial layer having a first doped ion, the first epitaxial layer having a first side and a second side opposite to each other; forming a second epitaxial layer located on the second side, the second epitaxial layer having a second doped ion, the second doped ion having a different electrical type from the first doped ion; forming a multi-quantum well layer located between the first epitaxial layer and the second epitaxial layer; and forming a photonic crystal structure used to optimize light emission parameters, the photonic crystal structure being located at least on one side of the first epitaxial layer.

[0026] Optionally, the photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side.

[0027] Optionally, the photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the second side.

[0028] Optionally, the photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side and the second side.

[0029] Optionally, the method for forming the photonic crystal structure includes: forming a conductive layer located on the first side; forming a plurality of dielectric holes in the conductive layer, and forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes; and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

[0030] Optionally, the method for forming the photonic crystal structure includes: forming a second insulating layer located on the first side; having a plurality of dielectric holes in the second insulating layer, and forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes; and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

[0031] Optionally, the method for forming the photonic crystal structure includes: forming a plurality of dielectric holes in the second epitaxial layer, forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes, and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

[0032] Optionally, the method for forming the photonic crystal structure includes: forming a first insulating layer located on the second side; forming a plurality of dielectric holes in the first insulating layer, and forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes; and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

[0033] Optionally, after forming the first epitaxial layer, the method further includes: forming a plurality of first epitaxial grooves in the first epitaxial layer; and after forming the first epitaxial layer, the method further includes: forming a plurality of second epitaxial grooves in the second epitaxial layer; wherein the plurality of first epitaxial grooves and the plurality of second epitaxial grooves correspond to each other along the stacking direction of the first epitaxial layer and the second epitaxial layer.

[0034] Optionally, after forming the first epitaxial groove, the method further includes forming a pixel isolation layer on the sidewall and bottom surface of the first epitaxial groove.

[0035] Optionally, after forming the first epitaxial groove, the method further includes: forming an epitaxial electrode layer within the first epitaxial groove, wherein the epitaxial electrode layer is electrically connected to the first epitaxial layer.

[0036] Optionally, the sidewall of the epitaxial electrode layer is an inclined surface, and the projection area of ​​the surface of the epitaxial electrode layer away from the first epitaxial layer toward the first epitaxial layer is located within the projection area of ​​the surface of the epitaxial electrode layer close to the first epitaxial layer toward the first epitaxial layer.

[0037] Optionally, the height of the epitaxial electrode layer is greater than the depth of the first epitaxial groove.

[0038] Optionally, after forming the second epitaxial groove, the method further includes forming a metal reflective layer within the second epitaxial groove.

[0039] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0040] In the micro-light-emitting diode chip of this invention, the photonic crystal structure is a medium with a periodic refractive index change. Increasing the photonic crystal structure can influence the propagation behavior of light. Depending on the depth and morphology of the aperture in the medium, the photonic crystal structure can function as a diffraction grating to control the emission angle and wavelength, or as an anti-reflection grating, thereby increasing the light emission at small angles and improving the light output. Furthermore, the photonic crystal structure can be tuned by adjusting lattice parameters, morphology, size, or material to control the photonic bandgap, thereby optimizing the light extraction efficiency.

[0041] Furthermore, it also includes a pixel isolation layer located on the sidewalls and bottom surface of the first epitaxial groove. The pixel isolation layer can prevent light emitted from between pixel units from interfering with each other. At the same time, the pixel isolation layer can also reflect light, causing light to scatter outward from the top of the first epitaxial layer, thereby improving the light extraction efficiency of the micro light-emitting diode chip.

[0042] Furthermore, the sidewalls of the epitaxial electrode layer are inclined surfaces, and the projection area of ​​the surface of the epitaxial electrode layer away from the first epitaxial layer toward the first epitaxial layer is located within the projection area of ​​the surface of the epitaxial electrode layer close to the first epitaxial layer toward the first epitaxial layer. By making the sidewalls of the epitaxial electrode layer inclined surfaces, the reflective area of ​​the epitaxial electrode layer can be effectively increased, and light can be better scattered outward from the top of the first epitaxial layer, thereby improving the light extraction efficiency of the micro LED chip.

[0043] Furthermore, the height of the epitaxial electrode layer is greater than the depth of the first epitaxial groove. By increasing the height of the epitaxial electrode layer, more light emitted from the pixel unit can be reflected, thereby improving the light extraction efficiency of the micro LED chip.

[0044] Furthermore, it also includes a metal reflective layer located within the second epitaxial groove. By providing a metal reflective layer within the second epitaxial groove, light emitted toward the second epitaxial layer can be reflected, thereby enabling as much light as possible to exit from the light-emitting surface of the pixel unit, thus improving the light extraction efficiency of the micro LED chip.

[0045] In the method for forming a micro-light-emitting diode chip according to the technical solution of the present invention, a photonic crystal structure is a medium with a periodic refractive index change. By forming a photonic crystal structure, the propagation behavior of light can be affected. Depending on the different depths and morphologies of the apertures in the medium, the photonic crystal structure can function as a diffraction grating to control the emission angle and wavelength, or as an anti-reflection grating, thereby increasing the emission at small angles and improving the light output. The photonic crystal structure can also control the photonic bandgap by adjusting lattice parameters, morphology, size, or material, thereby optimizing the light extraction efficiency.

[0046] Furthermore, after forming the first epitaxial groove, the method further includes forming a pixel isolation layer on the sidewall and bottom surface of the first epitaxial groove. The pixel isolation layer can prevent light emitted from pixel units from interfering with each other. At the same time, the pixel isolation layer can also reflect light, causing light to scatter outward from the top of the first epitaxial layer, thereby improving the light extraction efficiency of the micro light-emitting diode chip.

[0047] Furthermore, the sidewalls of the epitaxial electrode layer are inclined surfaces, and the projection area of ​​the surface of the epitaxial electrode layer away from the first epitaxial layer toward the first epitaxial layer is located within the projection area of ​​the surface of the epitaxial electrode layer close to the first epitaxial layer toward the first epitaxial layer. By making the sidewalls of the epitaxial electrode layer inclined surfaces, the reflective area of ​​the epitaxial electrode layer can be effectively increased, and light can be better scattered outward from the top of the first epitaxial layer, thereby improving the light extraction efficiency of the micro LED chip.

[0048] Furthermore, the height of the epitaxial electrode layer is greater than the depth of the first epitaxial groove. By increasing the height of the epitaxial electrode layer, more light emitted from the pixel unit can be reflected, thereby improving the light extraction efficiency of the micro LED chip.

[0049] Furthermore, after forming the second epitaxial groove, the method further includes forming a metal reflective layer within the second epitaxial groove. By providing a metal reflective layer within the second epitaxial groove, light emitted towards the second epitaxial layer can be reflected, thereby enabling as much light as possible to exit from the light-emitting surface of the pixel unit, thus improving the light extraction efficiency of the micro LED chip. Attached Figure Description

[0050] Figures 1 to 10 This is a schematic diagram of the structure of each step in a method for forming a miniature light-emitting diode chip according to an embodiment of the present invention;

[0051] Figure 11 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0052] Figure 12 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0053] Figure 13 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0054] Figure 14 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0055] Figure 15 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0056] Figure 16 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0057] Figure 17 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0058] Figure 18 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention;

[0059] Figure 19 This is a schematic diagram showing the different morphological structures of the first dielectric and the second dielectric in the micro light-emitting diode chip according to an embodiment of the present invention. Detailed Implementation

[0060] As described in the background section, existing miniature light-emitting diode (LED) chips still have many problems. These will be explained in detail below.

[0061] Currently, micro LED chips are grown on substrates such as sapphire, gallium arsenide, silicon carbide, or silicon. This heteroepitaxial growth usually leads to high density of threaded dislocations, which is detrimental to the internal quantum efficiency and reliability of micro LED chips. The light emission efficiency and light emission amount need to be further improved.

[0062] Based on this, the present invention provides a micro light-emitting diode chip and a method for forming the same. A photonic crystal structure is a medium with a periodic refractive index variation; by increasing the photonic crystal structure, the propagation behavior of light can be affected. Depending on the depth and morphology of the aperture in the medium, the photonic crystal structure can function as a diffraction grating to control the emission angle and wavelength, or as an anti-reflection grating, thereby increasing the light emission at small angles and improving the light output. Furthermore, the photonic crystal structure can also control the photonic bandgap by adjusting lattice parameters, morphology, size, or material, thereby optimizing the light extraction efficiency.

[0063] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] In the description of this invention, it should be understood that the terms "upper," "lower," "top surface," "bottom surface," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the indicated position or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of the invention. Furthermore, the terms "first" and "second" are used only to distinguish an entity or operation from another entity or operation, and do not require or imply any actual relationship, order, or relative importance between these entities or operations.

[0065] Figures 1 to 10 This is a schematic diagram of the structure of each step in a method for forming a miniature light-emitting diode chip according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention; Figure 12 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to another embodiment of the present invention; Figure 19 This is a schematic diagram showing the different morphological structures of the first dielectric and the second dielectric in the micro light-emitting diode chip according to an embodiment of the present invention.

[0066] A first epitaxial layer is formed, wherein the first epitaxial layer contains a first doped ion and has a first side and a second side opposite to each other; a second epitaxial layer is formed, wherein the second epitaxial layer is located on the second side and contains a second doped ion, wherein the second doped ion and the first doped ion have different electrical types; a multi-quantum well layer is formed, wherein the multi-quantum well layer is located between the first epitaxial layer and the second epitaxial layer; and a photonic crystal structure is formed, wherein the photonic crystal structure is used to optimize the light emission parameters and the photonic crystal structure is located at least on one side of the first epitaxial layer.

[0067] In this embodiment, the photonic crystal structure is located on the second side. For the specific formation process of the first epitaxial layer, the second epitaxial layer, and the photonic crystal structure, please refer to [reference needed]. Figures 1 to 4 .

[0068] Please refer to Figure 1 Provide temporary substrate 100.

[0069] In this embodiment, the temporary substrate 100 is used as a temporary support structure in the flip-chip fabrication process of the micro light-emitting diode chip, and the temporary substrate 100 needs to be removed in subsequent processes.

[0070] Please refer to Figure 2 A first epitaxial layer 101 is formed on a temporary substrate 100. The first epitaxial layer 101 contains first doped ions. The first epitaxial layer 101 has a first side 1011 and a second side 1012 opposite to each other. The temporary substrate 100 is located on the first side 1011.

[0071] In this embodiment, the electrical type of the first doped ion is N-type.

[0072] It should be noted that in this embodiment, the first side 1011 is the front side of the micro LED chip, and the second side 1012 is the back side of the micro LED chip.

[0073] In this embodiment, the material of the first epitaxial layer 101 is gallium nitride.

[0074] Please refer to Figure 3 A multi-quantum well layer 102 and a second epitaxial layer 103 are sequentially stacked on the first epitaxial layer 101. The multi-quantum well layer 102 is located between the first epitaxial layer 101 and the second epitaxial layer 103. The second epitaxial layer 103 is located on the second side 1012. The second epitaxial layer 103 contains a second doped ion. The second doped ion has a different electrical type than the first doped ion.

[0075] In this embodiment, the electrical type of the second doped ion is P-type. The first epitaxial layer 101 and the second epitaxial layer 103 serve as the positive and negative electrodes of the micro-LED chip, respectively.

[0076] In this embodiment, the material of the second epitaxial layer 103 is gallium nitride.

[0077] Please refer to Figure 4 A photonic crystal structure 105 is formed, and the photonic crystal structure 105 is located on the second side 1012.

[0078] In this embodiment, the method for forming a photonic crystal structure 105 includes: forming a plurality of dielectric holes (not shown) in a second epitaxial layer 103, forming a first dielectric body 1051 between adjacent dielectric holes; forming a second dielectric body 1052 in the dielectric holes, and forming a photonic crystal structure 105 by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0079] It should be noted that the working principle of the photonic crystal structure 105 is mainly based on the periodic change of the refractive index of light (i.e., the first dielectric 1051 and the second dielectric 1052 exhibit periodic changes in the refractive index). This change generates an optical bandgap structure, thereby controlling the movement of light within the photonic crystal. The photonic crystal structure 105 can be understood as the periodic appearance of low-refractive-index material, such as artificially created air vacancies, at certain locations within a high-refractive-index material, forming a periodic structure. This structure is comparable to the wavelength of light waves, causing Bragg scattering of the light waves within the crystal lattice. Bragg scattering is an optical phenomenon caused by the periodic structure of the crystal lattice, causing light waves to propagate in a specific direction and allowing only specific frequencies to pass through. This characteristic allows the photonic crystal structure 105 to be used to fabricate optical components such as light filters and mirrors.

[0080] Another important characteristic of the photonic crystal structure 105 is the photonic bandgap, meaning that light waves of certain frequencies cannot propagate within the photonic crystal. This is because these frequencies of light interfere with the periodic structure of the photonic crystal structure 105, causing the light energy to be scattered or absorbed. The photonic bandgap phenomenon can be used to fabricate optical isolators and optical phase modulators, among other optical components. Furthermore, the interference between the periodic structure of the photonic crystal structure 105 and light waves also leads to the formation of diffraction gratings. By altering the periodic structure of the photonic crystal structure 105, the propagation direction and intensity of light can be controlled, allowing the photonic crystal structure 105 to be used to fabricate optical diffraction gratings and optical waveguides, among other optical components.

[0081] In summary, the working principle of the photonic crystal structure 105 is based on the periodic change of the refractive index of light. Through phenomena such as Bragg scattering, photonic bandgap, and diffraction grating, it achieves the control and manipulation of light, providing new possibilities for the design of optical components.

[0082] Therefore, in this embodiment, by forming a photonic crystal structure 105, the propagation behavior of light can be influenced. Depending on the different depths and morphologies of the dielectric aperture, the photonic crystal structure 105 can function as a diffraction grating to control the emission angle and wavelength, or as an anti-reflection grating, thereby increasing the emission at small angles to improve the light output. The photonic crystal structure 105 can also adjust the photonic bandgap by controlling lattice parameters, morphology, size, or material, thereby optimizing the light extraction efficiency.

[0083] It should be noted that in this embodiment, the first dielectric body 1051 between adjacent dielectric holes is the protruding second epitaxial layer 103, that is, the material of the first dielectric body 1051 is the same as the material of the second epitaxial layer 103.

[0084] In this embodiment, the second dielectric 1052 includes a transparent insulating material; the transparent insulating material includes SiO2 and SiN. x One or more of the following: SiON, TiO2, Al2O3, and air.

[0085] Please refer to Figure 19 In this embodiment, the morphological structure of the second medium 1052 includes one or more of the following: a pyramid, a cylinder, a square prism, a hexagonal prism, and a hemisphere.

[0086] Please continue to refer to this. Figure 19 In this embodiment, the morphological structure of the first medium 1051 includes one or more of the following: a polygonal pyramid, a cylinder, a square prism, a hexagonal prism, and a hemisphere.

[0087] In this embodiment, the second medium body 1052 and the first medium body 1051 have one or more differences in material, morphology, structure, and size.

[0088] It should be noted that the reflectivity R of the thin film has extreme values ​​when its optical thickness nh = (2m+1)λ / 4, m = 0, 1, 2... In this embodiment, when n1 / n2 > 1, the reflectivity is at its maximum and the transmission effect is the worst; when n1 / n2 < 1, the reflectivity is at its minimum and the transmission effect is the best. Wherein, the equivalent refractive index n = n1 2 / n2, λ is the working light wavelength, n1 is the refractive index of the first dielectric 1051, n2 is the refractive index of the first dielectric 1052, and h is the thickness of the first dielectric 1051 and the second dielectric 1052.

[0089] Please refer to Figure 5 After the photonic crystal structure 105 is formed, a number of second epitaxial grooves 106 are formed in the second epitaxial layer 103.

[0090] It should be noted that, in this embodiment, the purpose of forming a plurality of second epitaxial grooves 106 is to divide the second epitaxial layer 103 into a plurality of pixel units. A plurality of photonic crystal structures 105 are distributed within each pixel unit, that is, the plurality of photonic crystal structures 105 are located between adjacent second epitaxial grooves 106.

[0091] Please refer to Figure 6 A metal reflective layer 107 is formed in the second extensional groove 106.

[0092] By providing a metal reflective layer 107 in the second epitaxial groove 106, light emitted toward the second epitaxial layer 103 can be reflected, thereby enabling as much light as possible to be emitted from the light-emitting surface of the pixel unit, thus improving the light emission efficiency of the micro light-emitting diode chip.

[0093] In this embodiment, the material of the metal reflective layer 107 can be aluminum or silver.

[0094] In this embodiment, the metal reflective layer 107 adopts a stepped morphology that is compatible with the sidewall of the second epitaxial groove 106. The stepped metal reflective layer 107 can better cover the exposed area of ​​the second epitaxial groove 106, thereby achieving a better light reflection effect and reducing the problem of light leakage on the back of the micro light-emitting diode chip.

[0095] Please refer to Figure 11 In other embodiments, the metal reflective layer 107 can also adopt a filled structure. A gap often exists between the filled structure and the sidewall of the second epitaxial groove 106, which can easily lead to a small amount of light leakage. However, the formation process of the filled metal reflective layer 107 is simpler.

[0096] Please refer to Figure 12 In other embodiments, in order to overcome the problem that there is often a gap between the metal reflective layer 107 of the filled structure and the sidewall of the second epitaxial groove 106, resulting in a small amount of light leakage, an auxiliary metal reflective layer 200 can be formed to reflect the light exposed from the gap.

[0097] Please continue to refer to this. Figure 6 A first insulating layer 108 is formed on the second epitaxial layer 103. The first insulating layer 108 is located on the second side 1012. A metal reflective layer 107 is located inside the first insulating layer 108. A conductive plug 109 is formed inside the first insulating layer 108. The conductive plug 109 is electrically connected to the second epitaxial layer 103. The first insulating layer 108 exposes part of the surface of the conductive plug 109.

[0098] In this embodiment, the material of the first insulating layer 108 includes: SiO2 and SiN. x One or more of SiON, TiO2 and Al2O3.

[0099] It should be noted that in this embodiment, the conductive plug 109 is used to electrically connect the second epitaxial layer 103 so as to connect it to the subsequently provided driving backplane. The driving circuit in the driving backplane then supplies power to the second epitaxial layer 103 to enable the micro LED chip to emit light. The conductive plug 109 and the second epitaxial layer 103 are made of metal and semiconductor materials, respectively. Direct connection between the two would create a contact barrier; therefore, an ohmic contact layer (not shown) is added between the conductive plug 109 and the second epitaxial layer 103. Furthermore, the formation of the first insulating layer 108 requires multiple deposition steps, while the conductive plug 109 is formed after the formation of the first insulating layer 108 by etching corresponding plug openings (not shown) within the first insulating layer 108, and then filling the plug openings with metal material.

[0100] Please continue to refer to this. Figure 6 In this embodiment, in order to further reduce the problem of light leakage on the back of the micro LED chip, an additional metal layer 110 is added between the conductive plug 109 and the ohmic contact layer. The added metal layer 110 and the metal reflective layer 107 need to have an overlapping area along the direction of device stacking in order to avoid the generation of gaps between them at the junction, which would lead to light leakage.

[0101] Please continue to refer to this. Figure 12 In other embodiments, the added metal layer 110 and the auxiliary metal reflective layer 200 need to have an overlapping area along the direction of device stacking in order to avoid gaps at the junction between the two, which would lead to light leakage.

[0102] Please refer to Figure 7 A drive backplane 111 is provided, which is electrically connected to the conductive plug 109.

[0103] In this embodiment, the driving backplane 111 is configured to control multiple pixel units. The driving backplane 111 may be a TFT (Thin Film Transistor) board or an IC (Integrated Circuit) board.

[0104] Please continue to refer to this. Figure 7 After the drive backplate 111 is electrically connected to the conductive plug 109, the temporary substrate 100 is removed.

[0105] Please refer to Figure 8 After removing the temporary substrate 100, a plurality of first epitaxial grooves 112 are formed in the first epitaxial layer 101. The plurality of first epitaxial grooves 112 and a plurality of second epitaxial grooves 106 correspond to each other in the direction of stacking the first epitaxial layer 101 and the second epitaxial layer 103.

[0106] It should be noted that, in this embodiment, after forming a plurality of first epitaxial grooves 112 corresponding to the second epitaxial grooves 106, a plurality of pixel units of the micro light-emitting diode chip are formed, that is, each pixel unit includes a first epitaxial layer 101 between adjacent first epitaxial grooves 112, a second epitaxial layer 103 between adjacent second epitaxial grooves 106, and a multi-quantum well layer 102 between the first epitaxial layer 101 and the second epitaxial layer 103.

[0107] In this embodiment, the protrusions between adjacent first epitaxial grooves 112 in the first epitaxial layer 101 and between adjacent second epitaxial grooves 106 in the second epitaxial layer 103 can be cylindrical or frustum-shaped. When the protrusions are frustum-shaped, their small ends are positioned away from each other.

[0108] Please refer to Figure 9 After the first epitaxial groove 112 is formed, a pixel isolation layer 113 is formed on the sidewall and bottom surface of the first epitaxial groove 112.

[0109] The pixel isolation layer 113 can prevent light emitted from pixel units from interfering with each other. At the same time, the pixel isolation layer 113 can also reflect light, so that light is scattered outward from the top of the first epitaxial layer 101, thereby improving the light extraction efficiency of the micro light-emitting diode chip.

[0110] In this embodiment, the pixel isolation layer 113 is made of a transparent insulating material, including SiO2 and SiN. x One or more of SiON, TiO2 and Al2O3.

[0111] Please continue to refer to this. Figure 9 After forming the pixel isolation layer 113, an epitaxial electrode layer 114 is formed in the first epitaxial groove 112, and the epitaxial electrode layer 114 is electrically connected to the first epitaxial layer 101.

[0112] It should be noted that in this embodiment, since the epitaxial electrode layer 114 is a metallic material and the first epitaxial layer 101 is a semiconductor material, direct contact between the two would create a contact barrier. Therefore, a conductive layer 115 is formed to electrically connect the first epitaxial layer 101 and the epitaxial electrode layer 114. The conductive layer 115 is located on the first side 1011 and is an ohmic contact layer. Furthermore, the conductive layer 115 needs to be transparent and not block the front light emission of the micro LED chip. Therefore, indium tin oxide (ITO) can be used for the conductive layer 115. Additionally, the first epitaxial electrode layer also needs to be electrically connected to the driving backplane 111 so that the driving circuit in the driving backplane 111 can supply power to the first epitaxial layer 101.

[0113] In this embodiment, the sidewalls of the epitaxial electrode layer 114 are inclined surfaces, and the projection area of ​​the surface of the epitaxial electrode layer 114 away from the first epitaxial layer 101 toward the first epitaxial layer 101 is located within the projection area of ​​the surface of the epitaxial electrode layer 114 close to the first epitaxial layer 101 toward the first epitaxial layer 101. By making the sidewalls of the epitaxial electrode layer 114 inclined surfaces, the reflective area of ​​the epitaxial electrode layer 114 can be effectively increased, and light can be better scattered outward from the top of the first epitaxial layer 101, thereby improving the light extraction efficiency of the micro LED chip.

[0114] In this embodiment, the height of the epitaxial electrode layer 114 is greater than the depth of the first epitaxial groove 112. By increasing the height of the epitaxial electrode layer 114, as much light emitted by the pixel unit as possible can be reflected, thereby improving the light extraction efficiency of the micro LED chip.

[0115] Please refer to Figure 10 A plurality of microlenses 104 are formed on the conductive layer 115. The microlenses 104 are located on the first side 1011 and correspond to the pixel units.

[0116] In this embodiment, the microlens 104 has a hemispherical shape, and the hemispherical structure can further improve the light extraction efficiency of the micro light-emitting diode chip.

[0117] Accordingly, this invention also provides a miniature light-emitting diode chip, please refer to the following embodiments. Figure 10 The structure includes: a first epitaxial layer 101 having a first doped ion and having a first side 1011 and a second side 1012 opposite to each other; a second epitaxial layer 103 located on the second side 1012 and having a second doped ion, the second doped ion having a different electrical type from the first doped ion; a multi-quantum well layer 102 located between the first epitaxial layer 101 and the second epitaxial layer 103; and a photonic crystal structure 105 located on the second side 1012.

[0118] Photonic crystal structure 105 is a medium with a periodic refractive index variation. By adding photonic crystal structure 105, the propagation behavior of light can be affected. The photonic crystal structure 105 with mixed-depth dielectric apertures, depending on the different depths and morphologies of the dielectric apertures, can function as a diffraction grating to control the emission angle and wavelength, or as an anti-reflection grating, thereby increasing the emission at small angles to improve the light output. The photonic crystal structure 105 can also have its photonic bandgap controlled by adjusting lattice parameters, morphology, size, or material, thus optimizing the light extraction efficiency.

[0119] In this embodiment, the second epitaxial layer 103 has a plurality of dielectric holes, and a second dielectric body 1052 is provided in the dielectric holes; a first dielectric body 1051 is provided between adjacent dielectric holes; and a photonic crystal structure 105 is formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0120] In this embodiment, the second dielectric 1052 includes a transparent insulating material; the transparent insulating material includes SiO2 and SiN. x One or more of the following: SiON, TiO2, Al2O3, and air.

[0121] In this embodiment, the morphological structure of the second medium 1052 includes one or more of the following: a pyramid, a cylinder, a square prism, a hexagonal prism, and a hemisphere.

[0122] In this embodiment, the morphological structure of the first medium 1051 includes one or more of the following: a pyramid, a cylinder, a square prism, a hexagonal prism, and a hemisphere.

[0123] In this embodiment, the second medium body 1052 and the first medium body 1051 have one or more differences in material, morphology, structure, and size.

[0124] In this embodiment, the first epitaxial layer 101 has a plurality of first epitaxial grooves 112; the second epitaxial layer 103 has a plurality of second epitaxial grooves 106; the plurality of first epitaxial grooves 112 and the plurality of second epitaxial grooves 106 correspond to each other in the direction of stacking the first epitaxial layer 101 and the second epitaxial layer 103.

[0125] In this embodiment, a pixel isolation layer 113 is also included, located on the sidewalls and bottom surface of the first epitaxial groove 112. The pixel isolation layer 113 can prevent light emitted from pixel units from interfering with each other. At the same time, the pixel isolation layer 113 can also reflect light, causing light to scatter outward from the top of the first epitaxial layer 101, thereby improving the light extraction efficiency of the micro light-emitting diode chip.

[0126] In this embodiment, the pixel isolation layer 113 is made of a transparent insulating material.

[0127] In this embodiment, it further includes an epitaxial electrode layer 114 located in the first epitaxial groove 112, the epitaxial electrode layer 114 being electrically connected to the first epitaxial layer 101.

[0128] In this embodiment, the sidewalls of the epitaxial electrode layer 114 are inclined surfaces, and the projection area of ​​the surface of the epitaxial electrode layer 114 away from the first epitaxial layer 101 toward the first epitaxial layer 101 is located within the projection area of ​​the surface of the epitaxial electrode layer 114 close to the first epitaxial layer 101 toward the first epitaxial layer 101. By making the sidewalls of the epitaxial electrode layer 114 inclined surfaces, the reflective area of ​​the epitaxial electrode layer 114 can be effectively increased, and light can be better scattered outward from the top of the first epitaxial layer 101, thereby improving the light extraction efficiency of the micro LED chip.

[0129] In this embodiment, the height of the epitaxial electrode layer 114 is greater than the depth of the first epitaxial groove 112. By increasing the height of the epitaxial electrode layer 114, as much light emitted by the pixel unit as possible can be reflected, thereby improving the light extraction efficiency of the micro LED chip.

[0130] In this embodiment, a metal reflective layer 107 is also included, located within the second epitaxial groove 106. By providing the metal reflective layer 107 within the second epitaxial groove 106, light emitted toward the second epitaxial layer 103 can be reflected, thereby enabling as much light as possible to exit from the light-emitting surface of the pixel unit, thus improving the light extraction efficiency of the micro LED chip.

[0131] In this embodiment, the metal reflective layer 107 adopts a stepped morphology that is compatible with the sidewall of the second epitaxial groove 106. The stepped metal reflective layer 107 can better cover the exposed area of ​​the second epitaxial groove 106, thereby achieving a better light reflection effect and reducing the problem of light leakage on the back of the micro light-emitting diode chip.

[0132] Please continue to refer to this. Figure 11 In other embodiments, the metal reflective layer 107 can also adopt a filled structure. A gap often exists between the filled structure and the sidewall of the second epitaxial groove 106, which can easily lead to a small amount of light leakage. However, the formation process of the filled metal reflective layer 107 is simpler.

[0133] Please continue to refer to this. Figure 12 In other embodiments, in order to overcome the problem that there is often a gap between the metal reflective layer 107 of the filled structure and the sidewall of the second epitaxial groove 106, resulting in a small amount of light leakage, another metal reflective layer 107 can be formed to reflect the light exposed from the gap.

[0134] Figure 13 This is a schematic diagram of the structure of a micro light-emitting diode chip according to another embodiment of the present invention.

[0135] This embodiment is based on the above embodiment ( Figure 10 , Figure 11 or Figure 12 Based on the above embodiments, the method for forming the micro light-emitting diode chip will continue to be described. The rest is the same as the above embodiments, except that the photonic crystal structure 105 is formed based on the first insulating layer 108. The following will be described in detail with reference to the accompanying drawings.

[0136] Please refer to Figure 13 A plurality of dielectric holes (not shown) are formed in the first insulating layer 108, and a first dielectric body 1051 is formed between adjacent dielectric holes; a second dielectric body 1052 is formed in the dielectric holes; and a photonic crystal structure 105 is formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0137] It should be noted that, in this embodiment, the first dielectric body 1051 between adjacent dielectric holes is the protruding first insulating layer 108, that is, the material of the first dielectric body 1051 is the same as the material of the first insulating layer 108.

[0138] It should be noted that in this embodiment, since the photonic crystal structure 105 is formed based on the first insulating layer 108 rather than the second epitaxial layer 103, the corresponding formation process needs to be adjusted. Specifically, after forming the second epitaxial layer 103, it is not necessary to etch several dielectric vias within the second epitaxial layer 103. Instead, after forming the first insulating layer 108, several dielectric vias are formed within the first insulating layer 108, and then the second dielectric body 1052 is formed within the dielectric vias. The formation of the remaining structures is the same as in the above embodiment and will not be described again here. Please refer to [reference needed] for details. Figures 1 to 10 As stated in the relevant explanations.

[0139] Accordingly, this invention also provides a miniature light-emitting diode chip, please refer to the following embodiments. Figure 13 The rest of the structure is the same as the micro light-emitting diode chip described in the above embodiment, except that the photonic crystal structure 105 is formed based on the first insulating layer 108.

[0140] In this embodiment, the first insulating layer 108 has a plurality of dielectric holes, and the dielectric holes have a second dielectric body 1052; a first dielectric body 1051 is provided between adjacent dielectric holes; the plurality of second dielectric bodies 1052 and the plurality of first dielectric bodies 1051 constitute a photonic crystal structure 105.

[0141] Figure 14 This is a schematic diagram of the structure of a micro light-emitting diode chip according to another embodiment of the present invention.

[0142] This embodiment is based on the above embodiment ( Figure 10 , Figure 11 or Figure 12Based on the above embodiments, the method for forming the micro light-emitting diode chip will continue to be described. The rest is the same as the above embodiments, except that the photonic crystal structure 105 is a double-layer structure, formed based on the second epitaxial layer 103 and the first insulating layer 108. The following will be described in detail with reference to the accompanying drawings.

[0143] Please refer to Figure 14 A plurality of dielectric holes (not shown) are formed in the second epitaxial layer 103 and the first insulating layer 108, and a first dielectric body 1051 is formed between adjacent dielectric holes; a second dielectric body 1052 is formed in the dielectric holes; and a photonic crystal structure 105 is formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0144] It should be noted that, in this embodiment, the first dielectric body 1051 between adjacent dielectric holes is the protruding second epitaxial layer 103 and the first insulating layer 108. That is, the first dielectric body 1051 is made of two materials, which are the same as the materials of the second epitaxial layer 103 and the first insulating layer 108, respectively.

[0145] It should be noted that in this embodiment, since the photonic crystal structure 105 is formed based on the second epitaxial layer 103 and the first insulating layer 108, the corresponding formation process needs to be adjusted. Specifically, after forming the second epitaxial layer 103, several dielectric holes are etched within it. After forming the first insulating layer 108, several dielectric holes are also formed within it, thereby forming the second dielectric body 1052 within the dielectric holes. The formation of the remaining structures is the same as in the above embodiment and will not be described again here. Please refer to [reference needed] for details. Figures 1 to 10 As stated in the relevant explanations.

[0146] Accordingly, this invention also provides a miniature light-emitting diode chip, please refer to the following embodiments. Figure 13 The rest of the structure is the same as the micro light-emitting diode chip described in the above embodiment, except that the photonic crystal structure 105 is a double-layer structure, formed based on the second epitaxial layer 103 and the first insulating layer 108.

[0147] In this embodiment, the second epitaxial layer 103 and the first insulating layer 108 have a plurality of dielectric holes, and the dielectric holes have a second dielectric body 1052; a first dielectric body 1051 is provided between adjacent dielectric holes; the plurality of second dielectric bodies 1052 and the plurality of first dielectric bodies 1051 constitute a photonic crystal structure 105.

[0148] Figure 15 This is a schematic diagram of the structure of a micro light-emitting diode chip according to another embodiment of the present invention.

[0149] This embodiment is based on the above embodiment ( Figure 10 , Figure 11 or Figure 12 Based on the above embodiments, the method for forming a micro light-emitting diode chip will continue to be described. The rest is the same as the above embodiments, except that the photonic crystal structure 105 is located on the first side 1011, and the photonic crystal structure 105 is formed based on the conductive layer 115. The following will be described in detail with reference to the accompanying drawings.

[0150] Please refer to Figure 15 A plurality of dielectric holes (not shown) are formed in the conductive layer 115, and a first dielectric body 1051 is formed between adjacent dielectric holes; a second dielectric body 1052 is formed in the dielectric holes; and a photonic crystal structure 105 is formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0151] It should be noted that in this embodiment, the first dielectric body 1051 between adjacent dielectric holes is the protruding conductive layer 115, that is, the material of the first dielectric body 1051 is the same as the material of the conductive layer 115.

[0152] It should be noted that in this embodiment, since the photonic crystal structure 105 is formed based on the conductive layer 115 rather than the second epitaxial layer 103, the corresponding formation process needs to be adjusted. Specifically, after forming the second epitaxial layer 103, it is not necessary to etch several dielectric vias within the second epitaxial layer 103. Instead, after forming the conductive layer 115, several dielectric vias are formed within the conductive layer 115, and then the second dielectric body 1052 is formed within the dielectric vias. The formation of the remaining structures is the same as in the above embodiment and will not be described again here. Please refer to [reference needed] for details. Figures 1 to 10 As stated in the relevant explanations.

[0153] It should be noted that, in this embodiment, it is not necessary to form a microlens 104.

[0154] Accordingly, this invention also provides a miniature light-emitting diode chip, please refer to the following embodiments. Figure 15 The rest of the structure is the same as the micro light-emitting diode chip described in the above embodiment, except that the photonic crystal structure 105 is located on the first side 1011 and the photonic crystal structure 105 is formed based on the conductive layer 115.

[0155] In this embodiment, the conductive layer 115 has a plurality of dielectric holes, and a second dielectric body 1052 is provided in the dielectric holes; a first dielectric body 1051 is provided between adjacent dielectric holes; the photonic crystal structure 105 is constituted by the plurality of second dielectric bodies 1052 and the plurality of first dielectric bodies 1051.

[0156] Figure 16 This is a schematic diagram of the structure of a micro light-emitting diode chip according to another embodiment of the present invention.

[0157] This embodiment is based on the above embodiment ( Figure 10 , Figure 11 or Figure 12 Based on the above embodiments, the method for forming a micro light-emitting diode chip will continue to be described. The rest is the same as the above embodiments, except that the photonic crystal structure 105 is located on the first side 1011, and the photonic crystal structure 105 is formed based on the second insulating layer 300. The following will be described in detail with reference to the accompanying drawings.

[0158] Please refer to Figure 16 A second insulating layer 300 is formed, which is located on the first side 1011. A plurality of dielectric holes (not shown) are provided in the second insulating layer 300, and a first dielectric body 1051 is formed between adjacent dielectric holes. A second dielectric body 1052 is formed in the dielectric holes. A photonic crystal structure 105 is formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0159] In this embodiment, the second insulating layer 300 is located on the conductive layer 115, and the material of the second insulating layer 300 includes: SiO2, SiN x One or more of SiON, TiO2 and Al2O3.

[0160] It should be noted that in this embodiment, the first dielectric body 1051 between adjacent dielectric holes is the protruding second insulating layer 300, that is, the material of the first dielectric body 1051 is the same as the material of the second insulating layer 300.

[0161] It should be noted that in this embodiment, since the photonic crystal structure 105 is formed based on the second insulating layer 300 rather than the second epitaxial layer 103, the corresponding formation process needs to be adjusted. Specifically, after forming the second epitaxial layer 103, it is not necessary to etch several dielectric vias within the second epitaxial layer 103. Instead, after forming the second insulating layer 300, several dielectric vias are formed within the second insulating layer 300, and then the second dielectric body 1052 is formed within the dielectric vias. The formation of the remaining structures is the same as in the above embodiment and will not be described again here. Please refer to [reference needed] for details. Figures 1 to 10 As stated in the relevant explanations.

[0162] It should be noted that, in this embodiment, it is not necessary to form a microlens 104.

[0163] Accordingly, this invention also provides a miniature light-emitting diode chip, please refer to the following embodiments. Figure 16 The rest of the structure is the same as the micro light-emitting diode chip described in the above embodiment, except that the photonic crystal structure 105 is located on the first side 1011 and the photonic crystal structure 105 is formed based on the second insulating layer 300.

[0164] In this embodiment, it further includes: a second insulating layer 300, the second insulating layer 300 being located on the first side 1011, the second insulating layer 300 having a plurality of dielectric holes, the dielectric holes having a second dielectric body 1052; a first dielectric body 1051 being between adjacent dielectric holes; and a photonic crystal structure 105 being formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0165] Figure 17 This is a schematic diagram of the structure of a micro light-emitting diode chip according to another embodiment of the present invention.

[0166] This embodiment is based on the above embodiment ( Figure 10 , Figure 11 or Figure 12 Based on the above embodiments, the method for forming a micro light-emitting diode chip will continue to be described. The rest is the same as the above embodiments, except that the photonic crystal structure 105 is located on the first side 1011, and the photonic crystal structure 105 is formed based on the conductive layer 115 and the second insulating layer 300. The following will be described in detail with reference to the accompanying drawings.

[0167] Please refer to Figure 17 A second insulating layer 300 is formed, which is located on the first side 1011; a plurality of dielectric holes (not shown) are provided in the conductive layer 115 and the second insulating layer 300, and a first dielectric body 1051 is formed between adjacent dielectric holes; a second dielectric body 1052 is formed in the dielectric holes; a photonic crystal structure 105 is formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0168] In this embodiment, the second insulating layer 300 is located on the conductive layer 115, and the material of the second insulating layer 300 includes: SiO2, SiN x One or more of SiON, TiO2 and Al2O3.

[0169] It should be noted that, in this embodiment, the first dielectric body 1051 between adjacent dielectric holes is the protruding conductive layer 115 and the second insulating layer 300. That is, the first dielectric body 1051 is made of two materials, which are the same as the materials of the second insulating layer 300.

[0170] It should be noted that in this embodiment, since the photonic crystal structure 105 is not formed based on the second epitaxial layer 103, but rather on the conductive layer 115 and the second insulating layer 300, the corresponding formation process needs to be adjusted. Specifically, after forming the second epitaxial layer 103, it is not necessary to etch several dielectric holes within the second epitaxial layer 103. Instead, after forming the conductive layer 115 and the second insulating layer 300, several dielectric holes are formed within the conductive layer 115 and the second insulating layer 300, thereby forming the second dielectric body 1052 within the dielectric holes. The formation of the remaining structures is the same as in the above embodiment and will not be described again here. Please refer to [reference needed] for details. Figures 1 to 10 As stated in the relevant explanations.

[0171] It should be noted that, in this embodiment, it is not necessary to form a microlens 104.

[0172] Accordingly, this invention also provides a miniature light-emitting diode chip, please refer to the following embodiments. Figure 16 The rest of the structure is the same as the micro light-emitting diode chip described in the above embodiment, except that the photonic crystal structure 105 is located on the first side 1011 and the photonic crystal structure 105 is formed based on the second insulating layer 300.

[0173] In this embodiment, it further includes: a second insulating layer 300, the second insulating layer 300 being located on the first side 1011, the second insulating layer 300 having a plurality of dielectric holes, the dielectric holes having a second dielectric body 1052; a first dielectric body 1051 being between adjacent dielectric holes; and a photonic crystal structure 105 being formed by a plurality of second dielectric bodies 1052 and a plurality of first dielectric bodies 1051.

[0174] Figure 18 This is a schematic diagram of the structure of a micro light-emitting diode chip according to another embodiment of the present invention.

[0175] This embodiment is based on the above embodiment ( Figure 10 , Figure 11 or Figure 12 Based on the above, the method for forming the micro light-emitting diode chip will continue to be described. The rest is the same as the above embodiment, except that the photonic crystal structure 105 is located on the first side 1011 and the second side 1012. The following will be described in detail with reference to the accompanying drawings.

[0176] It should be noted that, in this embodiment, Figure 18 Only shown in Figure 10 and Figure 15 When combined, the photonic crystal structure 105 is simultaneously located on the first side 1011 and the second side 1012.

[0177] In other embodiments, the combination is performed whenever a photonic crystal structure is formed on both the first and second sides, specifically as follows: Figure 10 and Figure 16 The combination of Figure 13 and Figure 15 The combination, and Figure 13 and Figure 16 The combinations are not listed here one by one. The corresponding adjustments to the process steps have been explained in the above embodiments and will not be repeated here.

[0178] Accordingly, this invention also provides a miniature light-emitting diode chip, please refer to the following embodiments. Figure 18 The rest of the structure is the same as the micro light-emitting diode chip described in the above embodiment, except that the photonic crystal structure 105 is located on the first side 1011 and the second side 1012.

[0179] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A miniature light-emitting diode chip, characterized in that, include: A first epitaxial layer, wherein the first epitaxial layer has a first doped ion, and the first epitaxial layer has a first side and a second side opposite to each other; The second epitaxial layer is located on the second side and contains a second doped ion, the second doped ion having a different electrical type from the first doped ion; A multi-quantum-well layer, wherein the multi-quantum-well layer is located between the first epitaxial layer and the second epitaxial layer; A photonic crystal structure for optimizing light emission parameters, wherein the photonic crystal structure is located at least on one side of the first epitaxial layer.

2. The micro light-emitting diode chip according to claim 1, characterized in that, The photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side.

3. The miniature light-emitting diode chip according to claim 1, characterized in that, The photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the second side.

4. The micro light-emitting diode chip according to claim 1, characterized in that, The photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side and the second side.

5. The micro light-emitting diode chip according to claim 2 or 4, characterized in that, Also includes: A conductive layer is located on the first side, and the conductive layer has a plurality of dielectric holes, each of which contains a second dielectric body; a first dielectric body is located between adjacent dielectric holes; the photonic crystal structure is composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

6. The micro light-emitting diode chip according to claim 2 or 4, characterized in that, Also includes: A second insulating layer is located on the first side, and the second insulating layer has a plurality of dielectric pores, the dielectric pores containing the second dielectric body. The first dielectric body is located between adjacent dielectric holes; the photonic crystal structure is composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

7. The micro light-emitting diode chip according to claim 3 or 4, characterized in that, The second epitaxial layer has a plurality of dielectric holes, and the dielectric holes contain a second dielectric body; a first dielectric body is located between adjacent dielectric holes; the photonic crystal structure is composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

8. The micro light-emitting diode chip according to claim 3 or 4, characterized in that, Also includes: A first insulating layer is located on the second side, and the first insulating layer has a plurality of dielectric pores, wherein the dielectric pores contain the second dielectric body. The first dielectric body is located between adjacent dielectric holes; the photonic crystal structure is composed of a plurality of second dielectric bodies and a plurality of first dielectric bodies.

9. The micro light-emitting diode chip according to claim 2, 3 or 4, characterized in that, The second dielectric material includes: a transparent insulating material; the transparent insulating material includes: SiO2, SiN x One or more of the following: SiON, TiO2, Al2O3, and air.

10. The micro light-emitting diode chip according to claim 2, 3 or 4, characterized in that, The morphological structure of the second medium includes one or more of the following: pyramidal, cylindrical, tetragonal prism, hexagonal prism, and hemispherical.

11. The micro light-emitting diode chip according to claim 2, 3 or 4, characterized in that, The morphological structure of the first medium includes one or more of the following: a pyramid, a cylinder, a square prism, a hexagonal prism, and a hemisphere.

12. The micro light-emitting diode chip according to claim 2, 3 or 4, characterized in that, The second medium and the first medium differ in one or more of their materials, morphology, and dimensions.

13. The micro light-emitting diode chip according to claim 1, characterized in that, The first epitaxial layer has a plurality of first epitaxial grooves; the second epitaxial layer has a plurality of second epitaxial grooves; the plurality of first epitaxial grooves and the plurality of second epitaxial grooves correspond to each other along the stacking direction of the first epitaxial layer and the second epitaxial layer.

14. The micro light-emitting diode chip according to claim 13, characterized in that, Also includes: Pixel isolation layer located on the sidewall and bottom surface of the first epitaxial groove.

15. The micro light-emitting diode chip according to claim 14, characterized in that, The pixel isolation layer is made of a transparent insulating material.

16. The micro light-emitting diode chip according to claim 15, characterized in that, Transparent insulating materials include: SiO2, SiN x One or more of the following: SiON, TiO2, Al2O3, and air.

17. The micro light-emitting diode chip according to claim 13, characterized in that, Also includes: An epitaxial electrode layer is located within the first epitaxial groove, and the epitaxial electrode layer is electrically connected to the first epitaxial layer.

18. The micro light-emitting diode chip according to claim 17, characterized in that, The sidewall of the epitaxial electrode layer is an inclined surface, and the projection area of ​​the surface of the epitaxial electrode layer away from the first epitaxial layer toward the first epitaxial layer is located within the projection area of ​​the surface of the epitaxial electrode layer close to the first epitaxial layer toward the first epitaxial layer.

19. The micro light-emitting diode chip according to claim 17, characterized in that, The height dimension of the epitaxial electrode layer is greater than the depth dimension of the first epitaxial groove.

20. The micro light-emitting diode chip according to claim 13, characterized in that, Also includes: A metal reflective layer located within the second epitaxial groove.

21. A method for forming a miniature light-emitting diode chip, characterized in that, include: A first epitaxial layer is formed, the first epitaxial layer contains a first doped ion, and the first epitaxial layer has a first side and a second side opposite to each other; A second epitaxial layer is formed, the second epitaxial layer is located on the second side, and the second epitaxial layer contains a second doped ion, the second doped ion and the first doped ion have different electrical types; A multi-quantum-well layer is formed, wherein the multi-quantum-well layer is located between the first epitaxial layer and the second epitaxial layer; A photonic crystal structure is formed, which is used to optimize the light emission parameters, and the photonic crystal structure is located at least on one side of the first epitaxial layer.

22. The method for forming a micro light-emitting diode chip according to claim 21, characterized in that, The photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side.

23. The method for forming a micro light-emitting diode chip according to claim 21, characterized in that, The photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the second side.

24. The method for forming a micro light-emitting diode chip according to claim 21, characterized in that, The photonic crystal structure includes: a plurality of first dielectric bodies and a plurality of second dielectric bodies, wherein the plurality of first dielectric bodies and the plurality of second dielectric bodies exhibit a periodic change in refractive index; the photonic crystal structure is located on the first side and the second side.

25. The method for forming a micro light-emitting diode chip according to claim 22 or 24, characterized in that, The method for forming the photonic crystal structure includes: forming a conductive layer located on the first side; forming a plurality of dielectric holes in the conductive layer, and forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes; and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

26. The method for forming a micro light-emitting diode chip according to claim 22 or 24, characterized in that, The method for forming the photonic crystal structure includes: forming a second insulating layer located on the first side; having a plurality of dielectric holes in the second insulating layer, and forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes; and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

27. The method for forming a micro light-emitting diode chip according to claim 23 or 24, characterized in that, The method for forming the photonic crystal structure includes: forming a plurality of dielectric holes in the second epitaxial layer, forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes, and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

28. The method for forming a micro light-emitting diode chip according to claim 23 or 24, characterized in that, The method for forming the photonic crystal structure includes: forming a first insulating layer located on the second side; forming a plurality of dielectric holes in the first insulating layer and forming a first dielectric body between adjacent dielectric holes; forming a second dielectric body in the dielectric holes; and forming the photonic crystal structure by the plurality of second dielectric bodies and the plurality of first dielectric bodies.

29. The method for forming a micro light-emitting diode chip according to claim 21, characterized in that, After forming the first epitaxial layer, the method further includes: forming a plurality of first epitaxial grooves in the first epitaxial layer; after forming the first epitaxial layer, the method further includes: forming a plurality of second epitaxial grooves in the second epitaxial layer; the plurality of first epitaxial grooves and the plurality of second epitaxial grooves correspond to each other along the stacking direction of the first epitaxial layer and the second epitaxial layer.

30. The method for forming a micro light-emitting diode chip according to claim 29, characterized in that, After forming the first epitaxial groove, the method further includes forming a pixel isolation layer on the sidewall and bottom surface of the first epitaxial groove.

31. The method for forming a micro light-emitting diode chip according to claim 29, characterized in that, After forming the first epitaxial groove, the method further includes: forming an epitaxial electrode layer within the first epitaxial groove, wherein the epitaxial electrode layer is electrically connected to the first epitaxial layer.

32. The method for forming a micro light-emitting diode chip according to claim 31, characterized in that, The sidewall of the epitaxial electrode layer is an inclined surface, and the projection area of ​​the surface of the epitaxial electrode layer away from the first epitaxial layer toward the first epitaxial layer is located within the projection area of ​​the surface of the epitaxial electrode layer close to the first epitaxial layer toward the first epitaxial layer.

33. The method for forming a micro light-emitting diode chip according to claim 31, characterized in that, The height dimension of the epitaxial electrode layer is greater than the depth dimension of the first epitaxial groove.

34. The method for forming a micro light-emitting diode chip according to claim 29, characterized in that, After forming the second epitaxial groove, the method further includes: forming a metal reflective layer within the second epitaxial groove.

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