Miniature light emitting diode (LED) structure

Abstract

An exemplary micro light emitting diode (LED) structure includes an array of micro LEDs. Each micro LED in the array comprises: a bottom epitaxial layer (4-3) of a first conductivity type; a light emitting layer (4-2) formed on the bottom epitaxial layer; a top epitaxial layer (4-1) of a second conductivity type formed on the light emitting layer; and a top contact layer (3) formed on the top epitaxial layer and having a continuous closed shape.

Description

Technical Field

[0001] This disclosure generally relates to the field of micro-LED technology, and more specifically, to micro-LED structures that limit current paths. Background Technology

[0002] Due to better strain relaxation, improved light extraction efficiency, and uniform current spread, micro-LEDs exhibit higher output performance than conventional LEDs. Compared to conventional LEDs, micro-LEDs also demonstrate improved thermal performance, higher current density, faster responsivity, a wider operating temperature range, higher resolution, a wider color gamut, higher contrast, and lower power consumption.

[0003] A microLED structure includes a pixel array. It typically comprises microlenses, a transparent conductive film layer (e.g., indium tin oxide or "ITO"), a top contact layer, an epitaxial wafer, an insulating layer, a reflective layer, a bottom contact layer, a dielectric layer, and an integrated circuit (IC) chip layer, wherein the epitaxial wafer further includes a top epitaxial layer, a light-emitting layer, and a bottom epitaxial layer. The top contact layer is used to amplify the current between adjacent pixels, and the bottom contact layer is bonded to the IC backplane.

[0004] However, in traditional micro-LED structures, the structure of the top contact layer results in poor current paths within the pixel array. Therefore, it is desirable to improve the structure of the top contact layer. Summary of the Invention

[0005] In view of the technical problems related to current paths in existing micro-LED structures, this application proposes an electrode metal layer with a special shape that can restrict current paths and improve the performance of micro-LED structures.

[0006] According to some disclosed embodiments, an exemplary structure for a micro-LED array is provided. The structure includes a micro-LED array. Each micro-LED in the array includes: a bottom epitaxial layer of a first conductivity type; a light-emitting layer formed on the bottom epitaxial layer; a top epitaxial layer of a second conductivity type formed on the light-emitting layer; and a top contact layer formed on the top epitaxial layer and having a continuous closed shape. Attached Figure Description

[0007] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0008] Figure 1 This is a schematic cross-sectional view of an exemplary microLED structure having a ring electrode, according to some embodiments of the present disclosure.

[0009] Figure 2 Based on some implementation schemes disclosed herein, Figure 1 Top view of the micro-LED structure (not shown) Figure 1 (Microlenses and ITO layer in the middle).

[0010] Figure 3 This is a schematic cross-sectional view of an exemplary micro-LED structure having circular electrodes, according to some embodiments of the present disclosure.

[0011] Figure 4 Based on some implementation schemes disclosed herein, Figure 3 Top view of the micro-LED structure (not shown) Figure 3 (Microlenses and ITO layer in the middle).

[0012] Figure 5 This is a schematic cross-sectional view of an exemplary microLED structure having annular-square electrodes, according to some embodiments of the present disclosure.

[0013] Figure 6 Based on some implementation schemes disclosed herein, Figure 5 Top view of the micro-LED structure (not shown) Figure 5 (Microlenses and ITO layer in the middle).

[0014] Figure 7 This is a cross-sectional view schematically showing a current path in an exemplary micro-LED structure having circular electrodes, according to some embodiments of the present disclosure.

[0015] Figure 8 This is a cross-sectional view schematically showing a current path in an exemplary microLED structure having a ring electrode, according to some embodiments of the present disclosure.

[0016] Figure 9 This is a cross-sectional view schematically showing the current path in an exemplary microLED structure having ring-square electrodes, according to some embodiments of the present disclosure. Detailed Implementation

[0017] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the drawings, and unless otherwise stated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following description of the exemplary embodiments do not represent all implementations consistent with this application. Rather, they are merely examples of apparatus and methods consistent with the aspects related to this application as described in the appended claims. Specific aspects of this disclosure are described below in more detail. In the event of any conflict with terms and / or definitions incorporated by reference, the terms and definitions provided herein shall prevail.

[0018] Figure 1 This is a schematic cross-sectional view of an exemplary microLED structure 100 having a restricted current path, according to some embodiments of the present disclosure. More specifically, the microLED structure 100 includes a pixel array implemented in a microLED display device. Figure 1 It shows a portion of the pixel array. For example... Figure 1 As shown, along the direction from the front side (i.e., the lens side) to the back side (i.e., the circuit side) of the microLED structure 100, it includes a microlens array 1, a top conductive layer 2, a top contact layer 3, an epitaxial wafer 4, an insulating layer 5, a reflective layer 6, a bottom contact layer 7, a bottom conductive structure 8, and an integrated circuit (IC) backplane 9. In some embodiments, the top conductive layer 2 is transparent and comprises indium tin oxide (ITO), and is therefore also referred to as "ITO layer 2". However, it is conceivable that the material of the top conductive layer 2 is not limited to ITO.

[0019] Furthermore, the top contact layer 3 is formed on the top epitaxial layer and continuously formed into a closed shape. In some embodiments, the closed shape includes: a circle, an annular shape, or an annular-square shape having an inner annular portion and a outer square portion. Furthermore, the top contact layer 3 is continuously formed on the top epitaxial layer in the microLED array. In some embodiments, the top contact layer 3 is formed at the edge of each microLED structure and around the central axis of each microLED structure.

[0020] Furthermore, the top epitaxial layer 4-1 includes a first trench between adjacent micro-LEDs; and the bottom epitaxial layer 4-3 includes a second trench between adjacent micro-LEDs. In this embodiment, the top contact layer 3 is formed on the surface of the top epitaxial layer 4-1 at the edge of the first trench. The first trench is formed at a location corresponding to the second trench.

[0021] More specifically, in Figure 1 In the illustrated embodiment, a bottom conductive structure 8 is disposed on the IC backplane 9. Specifically, the bottom conductive structure 8 includes a first dielectric layer 8-1 and a first array of contact holes 8-2 formed in the first dielectric layer 8-1. Each contact hole 8-2 may be cylindrical. A first metal fills the first array of cylindrical contact holes 8-2. An insulating layer 5 is filled into a second trench; furthermore, the insulating layer 5 is formed on the sidewalls and bottom of the second trench. A reflective layer 6 is formed on the surface of the insulating layer but is not connected to the contact holes 8-2.

[0022] Furthermore, in each microLED: a bottom contact pad 7 is formed on the bottom surface of the bottom epitaxial layer 4-3; an epitaxial layer 4 is formed on the bottom contact layer 7; an ITO layer 2 is formed on the epitaxial layer 4; a microlens 1 is formed on the ITO layer 2 and has a lens shape; and a top contact layer 3 is formed on the top epitaxial layer 4-3 between the epitaxial layer 4 and the ITO layer 2. The top contact layer 3 comprises a conductive material, such as a pure metal or a metal alloy. The bottom contact layer 7 comprises a conductive material, such as a pure metal or a metal alloy. Each microlens 1 includes a top hemispherical lens 1-1 and a lens base 1-2 below the top hemispherical lens 1-1. The width of the bottom spacer 1-2 is greater than the diameter of the top hemispherical lens. The height of the lens base 1-2 depends on the diameter of the top hemispherical lens 1-1; for example, the height of the lens base 1-2 increases as the diameter of the top hemispherical lens 1-1 increases. Gaps are formed between adjacent microlenses 1.

[0023] In some implementations, the ITO layer 2 comprises an N-type oxide semiconductor—indium tin oxide (ITO).

[0024] like Figure 1 As shown, in some embodiments, the epitaxial wafer 4 includes a top epitaxial layer 4-1, a light-emitting layer 4-2, and a bottom epitaxial layer 4-3. The top epitaxial layer 4-1 is a semiconductor epitaxial layer having a first conductivity type, and the bottom epitaxial layer 4-3 is a semiconductor epitaxial layer having a second conductivity type. As an example, the first conductivity type is N-type, and the second conductivity type is P-type. As another example, the first conductivity type is P-type, and the second conductivity type is N-type. The structure of these layers is described in detail below.

[0025] In particular, in some embodiments, the top epitaxial layer 4-1 may further include ( Figure 1 (Not shown): an n-GaAs (i.e., N-type GaAs) layer with a thickness of 10 nm to 1000 nm (including the endpoints); and / or an n-AlInP (i.e., N-type AlInP) layer of doped Si with a thickness of 10 nm to 10 μm (including the endpoints). The above exemplary values ​​are for illustrative purposes only and are not intended to limit this disclosure.

[0026] In some embodiments, to improve the light extraction efficiency within the micro-LED structure 101, the top epitaxial layer 4-1 is configured to form a plurality of photonic crystals 4-11 at the interface between the top epitaxial layer 4-1 and the ITO layer 2. Consistent with the disclosed embodiments, the plurality of photonic crystals 4-11 can be configured to have shapes and sizes suitable for improving light extraction efficiency. For example, as... Figure 1As shown, each of the plurality of photonic crystals 4-11 can be conical. As another example, each of the plurality of photonic crystals 4-11 has a height of approximately 300 nm and a diameter of approximately 266 nm, and adjacent photonic crystals 4-11 can be spaced approximately 50 nm apart. Nevertheless, the disclosed embodiments are not limited to any particular shape or size of the photonic crystals. For example, each of the plurality of photonic crystals 4-11 can be cylindrical (…). Figure 1 (Not shown in the image).

[0027] In some embodiments, the light-emitting layer 4-2 comprises one or more InGaP / AlGaInP quantum wells, each layer of which includes an InGaP sublayer and an AlGaInP sublayer. For example, the light-emitting layer 4-2 may comprise 1-20 layers of InGaP / AlGaInP quantum wells. As another example, in each layer of the InGaP / AlGaInP quantum well, the thickness of the InGaP sublayer is approximately 3.5 nm, and the thickness of the AlGaInP sublayer is approximately 6.5 nm. The above exemplary values ​​are for illustrative purposes only and are not intended to limit this disclosure.

[0028] In some implementations, to improve the wedge plug effect (WPE) performance of the quantum well, the light-emitting layer 4-2 is configured to form an integral interconnection structure on the pixel array, i.e., the light-emitting layer 4-2 is interconnected between adjacent pixels. "WPE" is defined as the ratio of optical output power measured at the wedge plug to the electrical input power consumed. By forming the light-emitting layer 4-2 as an integral interconnection structure on the pixel array, high WPE can be achieved in the micro-LED structure 101, thereby ensuring high performance of the LED display device.

[0029] In some embodiments, the bottom epitaxial layer 4-3 comprises a Mg-doped p-AlInP layer with a thickness of 50 nm to 300 nm (including the endpoints). These values ​​are for illustrative purposes only and are not intended to limit this disclosure.

[0030] like Figure 1 As shown, in some embodiments, the bottom epitaxial layer 4-3 forms an inverted trapezoidal array or a bowl-shaped array at the interface between the bottom epitaxial layer 4-3 and the bottom conductive structure 8.

[0031] Figure 1An exemplary structure for achieving the bonding between the bottom conductive structure 8 and the IC backplane 9 is also shown. The IC backplane 9 includes a second dielectric layer 9-1, a second array of contact holes 9-2 formed in the second dielectric layer 9-1, and a chip circuit board 9-3 formed beneath the second dielectric layer 9-1 and the second array of contact holes 9-2. Each contact hole 9-2 may be cylindrical. A second metal fills the second array of cylindrical contact holes 9-2. A first array of contact holes 8-2 forms a one-to-one relationship with the second array of contact holes 9-2. Each contact hole 8-2 may have a width (or diameter, if the contact hole 8-2 is cylindrical) larger than the width (or diameter) of the corresponding contact hole 9-2. The first metal in the first array of cylindrical contact holes 8-2 is bonded to the second metal in the second array of cylindrical contact holes 9-2. In summary, the arrays of the bottom contact layer 7 correspond to pixel arrays and are electrically connected to the first metal in the first array of contact holes 8-2, which are further electrically connected to the second metal in the second array of contact holes 9-2.

[0032] Figure 2 This is a top view of a micro-LED structure 100 according to some embodiments of this disclosure. To illustrate the structure of the top contact layer 3, Figure 2 Microlens 1 and ITO layer 2 are not shown. Furthermore, Figure 2 Only one pixel is shown in the top view. It can be assumed that the other pixels of the micro-LED structure 100 have the same top view structure. For example... Figure 1 and Figure 2 As shown in the diagram, in each pixel of the micro-LED structure 100, the top contact layer 3 is shaped as a ring (i.e., a ring) surrounding a plurality of photonic crystals 4-11. Figure 8 This is a schematic cross-sectional view of the current path in a micro-LED structure 100 according to some embodiments of the present disclosure. Figure 8 The arrows in the image show the current path in each pixel. (Example:) Figure 8 As shown, in each pixel, the annular top contact layer restricts the current path to each pixel, thereby reducing current crosstalk between adjacent pixels.

[0033] Consistent with the disclosed embodiments, the top contact layer 3 can have any shape suitable for limiting the current path. In addition... Figure 1 , Figure 2 and Figure 8 In addition to the annular top contact layer 3 shown, two alternative exemplary shapes of the top contact layer 3 are described below.

[0034] According to some implementation plans Figure 3 A schematic cross-sectional view of the micro-LED structure 200 is shown. Figure 4A schematic top view of a micro-LED structure 200 is shown. The micro-LED structure 200 includes a pixel array implemented in a micro-LED display device. Figure 3 It shows a portion of the pixel array. Figure 4 Only one pixel of the micro-LED structure 200 is shown. Microlens 1 and ITO layer 2 are excluded. Figure 4 In addition, to help illustrate the top view structure of the top contact layer 3 in each pixel. For example... Figure 3 and Figure 4 As shown, the micro-LED structure 200 is generally similar to the micro-LED structure 100. Figure 1 , Figure 2 and Figure 8 The difference lies in the shape of the top contact layer 3 in each pixel. Specifically, each pixel of the micro-LED structure 200 has a top contact layer 3 that is shaped like a circular plate in top view. Furthermore, in top view, the top contact layer 3 is typically located at the center of each pixel. Figure 7 This is a schematic cross-sectional view of the current path in a microLED structure 200 according to some embodiments of the present disclosure. Figure 7 The arrows in the image show the current path in each pixel. (Example:) Figure 7 As shown, in each pixel, the circular top contact layer restricts the current path to each pixel, thereby reducing current crosstalk between adjacent pixels.

[0035] According to some implementation plans Figure 5 A schematic cross-sectional view of the micro-LED structure 300 is shown. Figure 6 A schematic top view of a micro-LED structure 300 is shown. The micro-LED structure 300 includes a pixel array implemented in a micro-LED display device. Figure 5 It shows a portion of the pixel array. Figure 6 Only one pixel of the micro-LED structure 300 is shown. Microlens 1 and ITO layer 2 are excluded. Figure 6 In addition, to help illustrate the top view structure of the top contact layer 3 in each pixel. For example... Figure 5 and Figure 6 As shown, the micro-LED structure 300 is generally similar to the micro-LED structure 100. Figure 1 , Figure 2 and Figure 8 The difference lies in the shape of the top contact layer 3 in each pixel. Specifically, in the top view ( Figure 6 Each pixel of the micro-LED structure 300 has a top contact layer 3, which is shaped like a square with a circular opening at the center. Figure 5As shown in the cross-sectional view, the top contact layer 3 in each pixel has a peripheral portion formed in a groove between adjacent pixels, and an internal portion formed on the photonic crystal 4-11. In the top view ( Figure 6 The inner part is annular. Therefore, the shape of the top contact layer 3 in the micro-LED structure 300 is also referred to as an "annular-square" shape in three-dimensional view. The annular-square shape includes an inner annular part and a outer square part, which have different heights in cross-sectional view. Figure 5 In the top view ( Figure 6 The circular-square display is a square with a circular hollow center. Figure 9 This is a schematic cross-sectional view of the current path in a micro-LED structure 300 according to some embodiments of the present disclosure. Figure 9 The arrows in the image show the current path in each pixel. (Example:) Figure 9 As shown, in each pixel, the circular top contact layer restricts the current path to each pixel, thereby reducing current crosstalk between adjacent pixels.

[0036] In summary, as described above, each of the disclosed microLED structures (i.e., microLED structures 100-300) has a limited current path.

[0037] In summary, this disclosure provides a micro-LED structure with a restricted current path.

[0038] According to some disclosed embodiments, an exemplary micro-LED structure includes: an integrated circuit (IC) backplane; a bottom conductive structure disposed on the IC backplane; a reflective layer disposed on the bottom conductive structure, the reflective layer defining a pixel array; and an insulating layer disposed on the reflective layer. Each pixel includes: a bottom contact layer disposed on the bottom conductive structure; an epitaxial wafer disposed on the bottom contact layer; an indium tin oxide (ITO) layer disposed on the epitaxial wafer; a microlens disposed on the ITO layer; and a top contact layer disposed between the epitaxial wafer and the ITO layer. The epitaxial wafer of each pixel includes a top epitaxial layer, a light-emitting layer, and a bottom epitaxial layer. The top contact layer of each pixel has a circular, annular, or annular-square shape with an inner annular portion and a outer square portion.

[0039] The disclosed circular, annular, and annular-square top contact layers restrict the current path in the microLED structure.

[0040] Furthermore, in the disclosed micro-LED structure, the light-emitting layers are interconnected between adjacent pixels. This interconnected quantum well structure enhances the wedge plugging effect (WPE) performance of the micro-LED chip.

[0041] According to some publicly available implementations, multiple photonic crystals are formed at the interface between the top epitaxial layer and the ITO layer of each pixel. These photonic crystals are used to improve the light extraction efficiency of the micro-LED structure. The shape of the photonic crystals can be designed based on experimental data regarding light extraction efficiency. For example, the photonic crystals can be designed as cylindrical or conical shapes. Such shapes typically achieve satisfactory light extraction efficiency.

[0042] Consistent with the disclosed embodiments, photonic crystals can have any suitable height, diameter, and / or spacing. For example, a photonic crystal can have a height of 300 nm and / or a diameter of 266 nm. Adjacent photonic crystals can be spaced 50 nm apart.

[0043] This application further sets the following configuration: the top epitaxial layer between adjacent pixels is configured as an integral connection structure.

[0044] According to some disclosed embodiments, the top epitaxial layers are interconnected between adjacent pixels, thereby forming an interconnected structure across the pixel array. This interconnected top epitaxial layer facilitates current propagation. For example, the top epitaxial layers form a continuous bottom surface across the pixel array. In some embodiments, the bottom epitaxial layers are interconnected across the pixel array. For example, the bottom epitaxial layer forms a continuous top surface across the pixel array.

[0045] According to some publicly available implementations, the bottom epitaxial layer forms an inverted trapezoidal array or a bowl-shaped array at the interface between the bottom epitaxial layer and the bottom conductive structure. Therefore, the bottom of the inverted trapezoidal or bowl-shaped structure can reflect the light emitted by the quantum well to its periphery, thereby further focusing the light and improving light utilization.

[0046] According to some publicly available implementations, the ITO layer is an N-type oxide semiconductor—indium tin oxide (ITO). The ITO layer improves current spread between adjacent pixels.

[0047] According to some disclosed embodiments, the bottom conductive structure includes a first dielectric material and a first metal. A first array of cylindrical contact holes is formed in the first dielectric material, and the first metal fills the first array of cylindrical contact holes. Furthermore, the IC backplane includes a second dielectric layer, a second metal, and a circuit board. The second dielectric layer includes a second array of cylindrical contact holes, and the second metal fills the second array of cylindrical contact holes. The first metal in the first array of cylindrical contact holes is bonded to a second metal in the second array of cylindrical contact holes. Therefore, the bottom conductive structure is bonded to the IC backplane.

[0048] In summary, the disclosed microLED structure uses a top contact layer with a specially designed shape to limit the current path. For example, the top contact layer in each pixel can be circular, annular, or annular-square. Furthermore, quantum wells between adjacent pixels form an integral interconnect structure across the pixel array. This integral interconnected quantum well enhances the performance of the microLED chip. Additionally, the light extraction efficiency of the microLED structure is improved by etching an epitaxial wafer to form a photonic crystal. The shape of the photonic crystal can be designed based on experimental data regarding light extraction efficiency. For example, the photonic crystal can be designed as cylindrical or conical. Such shapes typically achieve satisfactory light extraction efficiency.

[0049] As used herein, unless otherwise specified, the term "or" covers all possible combinations unless impractical. For example, if a database is declared to include A or B, then unless otherwise specified or impractical, the database may include A or B, or A and B. As a second example, if a database is declared to include A, B, or C, then unless otherwise specified or impractical, the database may include A or B, or C, or A and B, or A and C, or B and C, or A, B, and C.

[0050] It should be understood that the embodiments of this disclosure are not limited to the exact constructions described above and illustrated in the accompanying drawings, and various modifications and changes can be made without departing from its scope. While this disclosure has been described in conjunction with multiple embodiments, other embodiments of this application will be apparent to those skilled in the art in light of the specification and embodiments of this application. This specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0051] The above description is intended to be illustrative and not limiting. Therefore, it will be apparent to those skilled in the art that modifications can be made as described without departing from the scope of the claims.

Claims

1. A micro LED structure, comprising: A micro LED array, wherein each micro LED in the array comprises: The bottom epitaxial layer of the first conductivity type (4-3); A light-emitting layer (4-2) is formed on the bottom epitaxial layer; A second conductivity type top epitaxial layer (4-1) is formed on the light-emitting layer; and The top contact layer (3) is formed on the top epitaxial layer and has a continuous closed shape.

2. The micro LED structure according to claim 1, wherein, The continuous closed shape includes: a circle, an annulus, or an annulus-square with an inner annulus portion and an outer square portion.

3. The micro LED structure according to claim 1, wherein, The top contact layer (3) is continuously formed on the top epitaxial layer (4-1) in the micro LED array.

4. The micro LED structure according to claim 1, wherein, The top contact layer (3) is formed at the edge of each microLED and around the central axis of each microLED.

5. The micro LED structure according to claim 1, wherein, The top contact layer (3) comprises a conductive material.

6. The micro LED structure according to claim 5, wherein, The conductive material of the top contact layer (3) is metal.

7. The micro LED structure according to claim 1, wherein, Each microLED in the array further includes a top conductive layer (2) formed on the top epitaxial layer (4-1) and the top contact layer (3).

8. The micro LED structure according to claim 7, wherein, The top conductive layer (2) is transparent and includes indium tin oxide (ITO).

9. The micro LED structure according to claim 1, wherein, The top epitaxial layer (4-1) includes a first trench between adjacent microLEDs.

10. The micro LED structure according to claim 9, wherein, The top contact layer (3) is formed at the edge of the first trench.

11. The micro-LED structure according to claim 9, wherein, The bottom epitaxial layer (4-3) includes a second trench formed at a position corresponding to the first trench.

12. The micro LED structure according to claim 1, wherein, Each microLED in the array further includes a microlens (1) formed above the top epitaxial layer (4-1).

13. The micro-LED structure according to claim 12, wherein, A gap is formed between the microlens (1) and the adjacent microlens (2).

14. The micro-LED structure according to claim 12, wherein, The microlens (1) includes a top hemispherical lens (1-1) and a bottom spacer (1-2) below the top hemispherical lens.

15. The micro-LED structure according to claim 14, wherein, The width of the bottom spacer (1-2) is greater than the diameter of the top hemispherical lens (1-1).

16. The micro-LED structure according to claim 12, wherein, The height of the bottom spacer (1-2) is determined based on the diameter of the top hemispherical lens (1-1).

17. The micro LED structure according to claim 1, wherein: The bottom epitaxial layer (4-2) includes a second trench between adjacent microLEDs; and Each microLED in the array further includes a reflective layer (6) formed on the sidewall of the second trench.

18. The micro LED structure according to claim 17, wherein, Each microLED in the array further includes an insulating layer (5) formed between the second trench and the reflective layer (6).

19. The micro-LED structure according to claim 18, wherein, Each microLED in the array further comprises: A bottom contact layer (7) is formed on the bottom surface of the bottom epitaxial layer (4-3); and A bottom conductive structure (8) is formed below the bottom contact layer (7) and the bottom epitaxial layer; The bottom contact layer (7) is surrounded by the insulating layer (5) and electrically connected to the bottom conductive structure (8).

20. The micro LED structure according to claim 1, wherein, Each microLED in the array further comprises: The bottom conductive structure (8) below the bottom epitaxial layer (4-3); and An IC backplane (9) is formed below the bottom conductive structure (8) and electrically connected to the bottom conductive structure (8).

21. The micro LED structure according to claim 20, wherein: The bottom conductive structure (8) includes a first dielectric layer (8-1) and a first contact hole (8-2) formed in the first dielectric layer (8-1); and The IC backplane (9) includes a second dielectric layer (9-1) and a second contact hole (9-2) formed in the second dielectric layer (9-1), the second contact hole (9-2) corresponding to the first contact hole (8-2).

22. The micro-LED structure according to claim 21, wherein, The width of the first contact hole (8-2) is greater than the width of the second contact hole (9-2).

23. The micro LED structure according to claim 21, wherein, A first metal is filled in the first contact hole (8-2), and a second metal is filled in the second contact hole (9-2).

24. The micro LED structure according to claim 23, wherein the first metal in the first contact hole (9-1) is bonded to the second metal in the second contact hole (9-2).

25. The micro LED structure according to claim 21, wherein, The IC backplane (9) further includes: A chip circuit board (9-3) is formed beneath the second dielectric layer (9-1) and the second contact hole (9-2).

26. The micro LED structure according to claim 1, wherein, The top epitaxial layer (4-1) includes multiple photonic crystals (4-11).

27. The micro LED structure according to claim 26, wherein, Each of the plurality of photonic crystals has a cylindrical or conical shape.

28. The micro LED structure according to claim 26, wherein, Each of the plurality of photonic crystals has a height of 300 nm and a diameter of 266 nm, and adjacent photonic crystals are spaced 50 nm apart.

29. The micro LED structure according to claim 1, wherein, The top epitaxial layer (4-1) is interconnected between adjacent microLEDs.

30. The micro LED structure according to claim 29, wherein, The top epitaxial layer (4-1) spans the micro-LED array to form a continuous bottom surface.

31. The micro LED structure according to claim 1, wherein, The light-emitting layers (4-2) are interconnected between adjacent micro-LEDs.

32. The micro LED structure according to claim 1, wherein, The bottom epitaxial layer (4-3) is interconnected between adjacent micro-LEDs.

33. The micro-LED structure according to claim 32, wherein, The bottom epitaxial layer (4-3) spans the micro-LED array to form a continuous top surface.

34. The micro LED structure according to claim 1, wherein, The bottom epitaxial layer (4-3) forms an inverted trapezoid or bowl shape.

35. The micro LED structure according to claim 1, wherein: The first conductivity type is N-type, and the second conductivity type is P-type; or The first conductivity type is P-type, and the second conductivity type is N-type.

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