Micro LED Structure and Micro LED Panel

Abstract

The present disclosure provides a micro LED structure and a full-color micro LED panel. The disclosed micro LED structure includes an IC backplane, at least three mesa structures stacked along a vertical axis, and a top contact formed above the at least three mesa structures. The second mesa structure includes a first connection layer, a first reflective layer formed on the first connection layer, a first bonding layer formed on the first reflective layer, a first light-emitting layer formed on the first bonding layer, and a second connection layer formed on the first light-emitting layer. The third mesa structure includes a second reflective layer formed on the second connection layer, a second bonding layer formed on the second reflective layer, a second light-emitting layer formed on the second bonding layer, and a third connection layer formed on the second light-emitting layer.

Description

[Technical Field]

[0001] The present disclosure relates generally to micro light emitting diode (LED) manufacturing techniques, and more particularly to micro LED structures and micro LED panels using the micro LED structures. [Background technology]

[0002] Inorganic micro light-emitting diodes (LEDs), also known as "micro-LEDs," are becoming increasingly important for their use in a variety of applications, including light-emitting microdisplays, visible light communications, and optogenetics. Micro-LEDs have higher output power than conventional LEDs due to better strain relief, improved light extraction efficiency, and uniform current spreading. Furthermore, compared to conventional LEDs, micro-LEDs have improved thermal efficiency, improved operation at higher current densities, better response speeds, a higher operating temperature range, higher resolution, a higher color gamut, higher contrast, and lower power consumption.

[0003] Micro LED panels are manufactured by integrating an array of thousands or millions of micro LEDs with a driver circuit back panel. Each pixel of a micro LED panel is formed by one or more micro LEDs. Micro LED panels can be single-color or multi-color panels. In particular, in the case of multi-color LED panels, each pixel can further include multiple sub-pixels formed by multiple micro LEDs, each corresponding to a different color. For example, three micro LEDs corresponding to red, green, and blue, respectively, can be stacked to form one pixel. Different colors can be mixed to produce a wide range of colors.

[0004] However, existing micro LED technology faces several challenges. For example, one challenge is improving the effective illumination area within each pixel when the distance between adjacent LEDs is determined. Furthermore, once the single LED illumination area is determined, it can be a difficult task to further improve the overall resolution of a micro LED panel because micro LEDs of different colors must occupy designated zones within a single pixel.

[0005] Furthermore, the light emitted by the LED die is generated from spontaneous emission and is therefore not directional, resulting in a large divergence angle. A large divergence angle can cause various problems in micro-LED panels. On the one hand, due to the large divergence angle, only a small portion of the light emitted by the micro-LED can be utilized. This can significantly reduce the efficiency and brightness of the micro-LED display system. On the other hand, due to the large divergence angle, the light emitted by one micro-LED pixel can illuminate its neighboring pixels, resulting in optical crosstalk between pixels, loss of clarity, and loss of contrast. Summary of the Invention

[0006] The present disclosure provides a micro LED structure that addresses problems in the related art, such as those mentioned above. In particular, the disclosed micro LED structure integrates two or more vertically stacked micro LEDs by arranging the micro LED structures in different layers of the micro LED structure and electrically connecting the micro LED structures to an integrated circuit (IC) back panel. The micro LED structure effectively improves the light illumination efficiency within a single pixel area and simultaneously improves the resolution of the micro LED panel.

[0007] Additionally, the disclosed micro LED structure further improves light illumination efficiency by including a reflective layer that not only effectively increases the amount of light emitted by each of the vertically stacked micro LEDs, but also reduces crosstalk between the vertically stacked micro LEDs.

[0008] Consistent with the disclosed embodiments, a plurality of the disclosed micro LED structures can be arranged in a micro LED array to form a micro LED panel, with each of the plurality of micro LED structures corresponding to a pixel of the disclosed micro LED structure and with multiple vertically stacked micro LEDs within a pixel corresponding to multiple sub-pixels, respectively.

[0009] In some embodiments, the disclosed micro LED structure comprises an IC backplane, at least three mesa structures stacked along a vertical axis, and a top contact formed above the at least three mesa structures.

[0010] In some embodiments, the at least three mesa structures comprise a first mesa structure formed on the IC backplane, a second mesa structure formed on the first mesa structure, and a third mesa structure formed on the second mesa structure.

[0011] In some embodiments, the second mesa structure comprises a first connecting layer, a first reflective layer formed on the first connecting layer, a first bonding layer formed on the first reflective layer, a first light emitting layer formed on the first bonding layer, and a second connecting layer formed on the first light emitting layer. In some embodiments, the first light emitting layer comprises a first semiconductor layer and a second semiconductor layer formed on the first semiconductor layer.

[0012] In some embodiments, the third mesa structure comprises a second reflective layer formed on the second connecting layer, a second bonding layer formed on the second reflective layer, a second light emitting layer formed on the second bonding layer, and a third connecting layer formed on the second light emitting layer. In some embodiments, the second light emitting layer comprises a third semiconductor layer and a fourth semiconductor layer formed on the third semiconductor layer.

[0013] In some embodiments, the first connection layer and the third connection layer are electrically connected to an IC backplane.

[0014] In some embodiments, the second connection layer is connected to the top contact.

[0015] In some embodiments, the first semiconductor layer and the fourth semiconductor layer have a first conductivity type, and the second semiconductor layer and the third semiconductor layer have a second conductivity type.

[0016] In some embodiments, each of the light emitting layers comprises a P-type semiconductor layer, an N-type semiconductor layer, and a quantum well layer between the P-type and N-type semiconductor layers. For example, each of the light emitting layers may comprise a P-type semiconductor layer at the bottom and an N-type semiconductor layer at the top, thereby forming a PN junction, or each of the light emitting layers may comprise an N-type semiconductor layer at the bottom and a P-type semiconductor layer at the top, thereby forming an NP junction. [Brief explanation of the drawings]

[0017] [Figure 1] 1A-1C are cross-sectional views of micro LED structures according to some embodiments of the present disclosure. [Figure 2] FIG. 1 is a top view of an N-dot according to some embodiments of the present disclosure. [Figure 3] FIG. 1 illustrates a top view of an exemplary micro LED structure according to some embodiments of the present disclosure. [Figure 4] FIG. 1B is a top view of another exemplary micro LED structure according to some embodiments of the present disclosure. [Figure 5] FIG. 1 is a top view of an exemplary micro-LED panel, according to some embodiments of the present disclosure. [Figure 6] FIG. 1 is a top view of another exemplary micro-LED panel, according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0018] To provide a further understanding of the present disclosure, reference will now be made in detail to exemplary embodiments. The specific embodiments described and the accompanying drawings are merely illustrative of specific ways to make and use the disclosure and do not limit the scope of the disclosure or the appended claims.

[0019] FIG. 1 is a cross-sectional view of a micro LED structure 10 according to some embodiments of the present disclosure. As shown in FIG. 1, the micro LED structure 10 includes an IC backplane 900 and three mesa structures stacked along a vertical axis. Specifically, the first of the three mesa structures includes, from bottom to top, a conductive bonding layer 103, a light emitting layer 100 (e.g., a layer that emits red light), N-dots 102, and a top connection layer 101. As shown in FIG. 2, the N-dots 102 refer to dot-shaped contact pads in a plan view. The N-dots 102 are formed on the surface of an N-type semiconductor epitaxial layer (i.e., an "N-type epilayer"). The N-dots 102 include a conductive material, such as a metal, and form ohmic contacts on the N-type epilayer. 1 , the top connection layer 101 is electrically connected to the top of the light emitting layer 100 via the N-dots 102, and the conductive bonding layer 103 bonds the bottom of the light emitting layer 100 to the IC backplane 900. The second mesa structure of the micro LED structure 10 comprises, from bottom to top, a bottom connection layer 202, a reflective layer 204, a conductive bonding layer 203, a light emitting layer 200 (e.g., a layer that emits green light), and an interconnect layer 201. The interconnect layer 201 is electrically connected to the top of the light emitting layer 200, and the bottom connection layer 202 electrically connects the bottom of the reflective layer 204 to the IC backplane 900. The third mesa structure of the micro LED structure 10 comprises, from bottom to top, a reflective layer 304, a conductive bonding layer 303, a light emitting layer 300 (e.g., a layer that emits blue light), and a top connection layer 301. The interconnect layer 201 bonds to and electrically connects the light emitting layer 300 at the bottom of the reflective layer 304. The three mesa structures are stacked on an IC backplane 900, with a second mesa structure formed above the first mesa structure and a third mesa structure formed above the second mesa structure.

[0020] In some embodiments, sidewall connection structures 205 and 305 may be formed on the bottom connection layer 202 and the interconnect layer 201, respectively. Specifically, the sidewall connection structure 205 may be formed on the bottom connection layer 202 and surround the sidewalls of the reflective layer 204 and the conductive bonding layer 203. The sidewall connection structure 205 may provide electrical contact from its side to the conductive bonding layer 203. Similarly, the sidewall connection structure 305 may be formed on the interconnect layer 201 and surround the sidewalls of the reflective layer 304 and the conductive bonding layer 303. The sidewall connection structure 305 may provide electrical contact from its side to the conductive bonding layer 303.

[0021] 1 , in some embodiments, a dielectric material 700 may be filled between the top connecting layer 101 and the bottom connecting layer 202, thus forming a dielectric layer 701 therebetween. In some embodiments, the dielectric material 700 may fill gaps in the micro LED structure 10, thereby preventing the light emitting layers (e.g., light emitting layers 100, 200, 300) from being electrically connected to one another.

[0022] In some embodiments, light-emitting layers 100, 200, and 300 can emit different colors or light images. In some exemplary embodiments, light-emitting layer 100 is selected as a red light-emitting layer, light-emitting layer 200 is selected as a green light-emitting layer, and light-emitting layer 300 is selected as a blue light-emitting layer. The above color assignments are for illustrative purposes only. Consistent with the disclosed embodiments, other combinations of light colors can be assigned to the light-emitting layers to achieve any desired result.

[0023] In some embodiments, light emitting layers 100, 200, and 300 can each include two semiconductor layers of different conductivity types (e.g., P-type and N-type) and a quantum well layer between the two semiconductor layers of different types. In some embodiments, light emitting layers 100 and 200 can each have a P-type semiconductor layer at the bottom and an N-type semiconductor layer at the top, and light emitting layer 300 can have an N-type semiconductor layer at the bottom and a P-type semiconductor layer at the top. In some other embodiments, light emitting layers 100 and 200 can each have an N-type semiconductor layer at the bottom and a P-type semiconductor layer at the top, and light emitting layer 300 can have a P-type semiconductor layer at the bottom and an N-type semiconductor layer at the top.

[0024] When the mesa structures of the micro LED structure 10 are projected perpendicularly onto a horizontal plane, each mesa structure forms a projected area on the horizontal plane. Each projected area on the horizontal plane has a contour, which is referred to herein as a projected contour in a plan view (i.e., top view). In some embodiments, the disclosed micro LED structure is configured such that the projected contour of the upper light-emitting layer in the plan view is disposed within the projected shape of the lower light-emitting layer in the plan view, thereby forming multiple mesa structures with different widths. Specifically, FIG. 3 is a top view of the micro LED structure 10 of FIG. 1. As shown in FIG. 3, R, G, and B represent the areas of the light-emitting layers 100, 200, and 300 formed in the top view, respectively. In this exemplary embodiment, the projected contour of the light-emitting layer 300 is disposed within the projected contour of the light-emitting layer 200, and the projected contour of the light-emitting layer 200 is disposed within the contour of the light-emitting layer 100.

[0025]

[0031] Figure 4 schematically illustrates a top view of the micro LED structure 10 of Figure 1 according to another exemplary embodiment. As shown in Figure 4, the through-anode connection layer vias 500, 600 are formed in a direction parallel to adjacent edges of the mesa structure. The embodiments of Figures 3 and 4 are for illustrative purposes only. The through-common connection layer vias and the through-anode connection layer vias can be formed at any location within the micro LED area.

[0026] 5 is a top view of a micro LED panel 11 according to an exemplary embodiment. As shown in FIG. 5, the micro LED panel 11 includes an array of micro LED structures 10. As shown in FIG. 5, the top contact pads 401 of the multiple micro LED structures 10 in each row are connected to each other to form a continuous line. A shared contact pad 402 connects all the rows of the top contact pads 401 to each other. In this exemplary embodiment, the distribution direction of the through-anode connection layer vias 500, 600 is perpendicular to the distribution direction of the top contact pads 401.

[0027] 6 is a top view of a micro LED panel 11 according to another exemplary embodiment. As shown in FIG. 6, adjacent rows of micro LEDs share a single top contact pad 401. This arrangement allows for a higher integration density of the micro LED panel.

[0028] It should be noted that the cross-sectional arrangement of the micro LED structure 10 is not limited to the configuration shown in Figure 1. For example, in some exemplary embodiments, the sidewalls of the conductive bonding layers 103, 203, and 303 are optionally aligned with the sidewalls of the light emitting layers 100, 200, and 300, respectively. Specifically, the sidewalls of the conductive bonding layer 103 are aligned with the sidewalls of the light emitting layer 100, the sidewalls of the conductive bonding layer 203 are aligned with the sidewalls of the light emitting layer 200, and the sidewalls of the conductive bonding layer 303 are aligned with the sidewalls of the light emitting layer 300.

[0029] In some embodiments, the conductive bonding layer may be transparent or non-transparent. In some embodiments, the material of the conductive bonding layer is selected from one of metals, composite metals, or transparent conductive materials. In some embodiments, the transparent conductive material may be made of indium tin oxide (ITO) or aluminum-doped zinc oxide (AZO). The metal may be selected from copper (Cu), gold (Au), etc. In some embodiments, the thickness of the conductive bonding layer (e.g., 103, 203, 303) may be in the range of about 0.1 micron to about 5 microns. In some embodiments, the metal composition of the bonding layer may include Au-Au bonding, Au-Sn bonding, Au-In bonding, Ti-Ti bonding, Cu-Cu bonding, or a combination thereof. For example, if an Au-Au bond is required, two layers of Au each require a chromium (Cr) coating as an adhesion layer and a platinum (Pt) coating between the gold layer and the chromium coating as a diffusion barrier layer. Cr and Pt layers may be formed on both Au layers to be bonded. In some embodiments, when the thicknesses of the two Au layers to be bonded are approximately the same, the interdiffusion of Au on both Au layers can bond the two layers together under high pressure and high temperature. Exemplary bonding techniques can include eutectic bonding, thermocompression bonding, and transient liquid phase (TLP).

[0030] In some embodiments, the material of the connecting layer (e.g., 101, 201, 202, 301) may be selected from transparent conductive materials. In some embodiments, the transparent conductive material may be indium tin oxide (ITO). In some embodiments, the thickness of the ITO layer may be in the range of about 0.01 micron to about 1 micron.

[0031] In some embodiments, the second mesa structure and the third mesa structure are joined by interconnect layer 201. In some embodiments, the entire area of ​​light emitting layer 200 may be covered by interconnect layer 201, and therefore, the entire area may be utilized.

[0032] In some embodiments, a through-cathode connection layer via 400 filled with a conductive metal may be formed next to the light emitting layers 100, 200, 300 and next to the stack of mesa structures. In some exemplary embodiments, the through-cathode connection layer via 400 is electrically connected to the light emitting layers 100, 200, 300 through the connection layer 101 or the interconnect layer 201, as shown in FIG. 1 . In some embodiments, a top contact pad 401 may be formed on top of the through-cathode connection layer via 400. The top contact pad 401 may be electrically connected to circuitry external to the micro LED structure 10.

[0033] In some embodiments, at least one of the through-anode connection layer vias (e.g., 500, 600) may be formed adjacent to the stacked mesa structure of the micro LED structure 10. The through-anode connection layer vias 500, 600 are formed at a location separate from the location of the through-cathode connection layer vias 400. For example, the through-anode connection layer vias 500, 600 may be located on a different side of the mesa structure from the through-cathode connection layer vias 400. The through-vias 400, 500, 600 are not electrically connected to each other.

[0034] 1 , through-anode connection layer via 500 connects light-emitting layer 200 to IC backplane 900 through bottom connection layer 202. Also, through-anode connection layer via 600 connects light-emitting layer 300 to IC backplane 900 through top connection layer 301. In this exemplary embodiment, light-emitting layer 100 is electrically connected to IC backplane 900 through conductive bonding layer 103, and therefore no through-connection layer via is required to connect light-emitting layer 100 to IC backplane 900.

[0035] In some embodiments, reflective layers 204 and 304 are formed on the bottom connection layer 202 and the interconnect layer 201, respectively. Specifically, the reflective layer 204 may be sandwiched between the bottom connection layer 202 and the conductive bonding layer 203, and the reflective layer 304 may be sandwiched between the interconnect layer 201 and the conductive bonding layer 303. Similarly, the sidewalls of the reflective layers 204 and 304 are aligned with the sidewalls of the conductive bonding layers 203 and 303 of the mesa structures, respectively. For example, in the middle mesa structure, the reflective layer 204 is formed on the bottom surface of the conductive bonding layer 203, and the sidewalls of the conductive bonding layer 203 are aligned with the sidewalls of the corresponding reflective layer 204. In the upper mesa structure, the reflective layer 304 is formed on the bottom surface of the conductive bonding layer 303, and the sidewalls of the conductive bonding layer 303 are aligned with the sidewalls of the corresponding reflective layer 304. In some embodiments, each of the reflective layers of the micro LED structure 30 comprises a stacked transparent layer and a metal ODR layer, a stacked DBR layer, or a high reflectivity metal. Note that the reflective layer may be insulating (DBR) or conductive (metal reflector). In the case of an insulating reflective layer, electrical contact from the connecting layer to the light emitting layer may be made by a sidewall connecting structure (e.g., 205, 305).

[0036] In some embodiments, each of the above-mentioned reflective layers (e.g., 204, 304) may be or comprise a distributed Bragg reflector (DBR) structure or a metallic reflector. For example, the reflective layer may be formed by stacking multiple layers of alternating or dissimilar materials with varying refractive indices. In some embodiments, each layer boundary of the DBR structure may cause partial reflection of light waves. In some embodiments, the reflective layer is made of multiple layers of SiO2 and Ti3O5. In some embodiments, the reflective layer is made of multiple layers of Au and / or indium tin oxide (ITO). By manipulating the thickness and / or number of the SiO2 and Ti3O5 layers or the thickness and / or number of the Au and / or ITO layers, selective reflection or transmission of specific wavelengths of light can be achieved. For example, in an exemplary design, the reflective layer 204 in FIG. 1 reflects red light, and the reflective layer 304 in FIG. 1 reflects green light. For example, the DBR structure shown in Table 1 below may be used for the reflective layer that reflects green light from a green light-emitting layer. TIFF2026500054000002.tif108170

[0037] In some embodiments, the reflective layer 304 of the green light LED structure may have low absorption (e.g., 5% or less) of the light generated by the different layers of the three-color LED device. In some embodiments, the reflective layer 304 of the green light layer has high reflectivity (e.g., 95% or more) of the light generated thereon, e.g., green and blue light.

[0038] In some exemplary embodiments, the light emitting layer 100 of the micro LED structure 10 (FIG. 1) is designed to emit red light. Examples of red light emitting layers include III-V nitride, III-V arsenide, III-V phosphide, and III-V antimonide epitaxial structures. In some embodiments, the films in the red light emitting layer may include layers of P-type GaP / P-type InGaN light emitting layer / InGaN / N-type InGaN / N-type GaAs. In some embodiments, the P-type may be Mg-doped and the N-type may be Si-doped. In some embodiments, the thickness of the light emitting layer 100 may be in the range of about 0.3 microns to about 5 microns.

[0039] In some embodiments, the light emitting layer 200 of the micro LED structure 10 (FIG. 1) is designed to emit green light. Examples of green light emitting layers include III-V nitride, III-V arsenide, III-V phosphide, and III-V antimonide epitaxial structures. In some embodiments, the films in the green light emitting layer 200 may include a P-type GaN / InGaN light emitting layer / N-type GaN layer. In some embodiments, the P-type may be Mg-doped and the N-type may be Si-doped. In some embodiments, the thickness of the light emitting layer 200 may be in the range of about 0.3 microns to about 5 microns.

[0040] In some embodiments, the light emitting layer 300 of the micro LED structure 10 (FIG. 1) is designed to emit blue light. Examples of blue light emitting layers include III-V nitride, III-V arsenide, III-V phosphide, and III-V antimonide epitaxial structures. In some embodiments, the films in the blue light emitting layer 300 may include a P-type GaN / InGaN light emitting layer / N-type GaN layer. In some embodiments, the P-type may be Mg-doped and the N-type may be Si-doped. In some embodiments, the thickness of the blue light emitting layer 300 may be in the range of about 0.3 microns to about 5 microns.

[0041] In some embodiments, in the micro LED structure 10 (FIG. 1), the top connecting layer of the micro LED structure (e.g., top connecting layer 301) is deposited on the light emitting layer 300. In some embodiments, the thickness of the top connecting layer 301 (ITO layer) can be from about 0.01 micron to about 1 micron.

[0042] In some embodiments, the microlens 800 may be formed on top of a micro LED structure (eg, the micro LED structure shown in FIG. 1).

[0043] The micro LEDs described in the disclosed embodiments have a very small volume. The micro LEDs may be organic or inorganic LEDs. In some embodiments, the micro LEDs may be applied to a micro LED array panel. The light-emitting area of ​​the micro LED array panel may be very small, e.g., 1 mm x 1 mm, 3 mm x 5 mm, etc. In some embodiments, the light-emitting area may be the area of ​​the micro LED array within the micro LED array panel. The micro LED array panel may include one or more micro LED arrays forming a pixel array, e.g., a 1600 x 1200, 680 x 480, or 1920 x 1080 pixel array, in which the micro LEDs are pixels. The diameter of the micro LEDs may be in the range of approximately 200 nm to 2 μm. In some embodiments, an IC backplane may be formed on the backside of the micro LED array and electrically connected to the micro LED array. In some embodiments, the IC backplane may receive signals, such as image data, from an external device via signal lines to control the on / off (e.g., whether to emit light) of the corresponding micro LEDs.

[0044] Thus, different types of display panels can be fabricated. For example, in some embodiments, the resolution of the display panel can range from 8x8 to 3840x2160. Common display resolutions include QVGA, which has a 320x240 resolution and a 4:3 aspect ratio; XGA, which has a 1024x768 resolution and a 4:3 aspect ratio; D, which has a 1280x720 resolution and a 16:9 aspect ratio; FHD, which has a 1920x1080 resolution and a 16:9 aspect ratio; UHD, which has a 3840x2160 resolution and a 16:9 aspect ratio; and 4K, which has a 4096x2160 resolution and a 1.9 aspect ratio. A wide variety of pixel sizes can also exist, ranging from submicron to 10mm or larger. The size of the overall display area can also vary greatly, ranging from small diagonals of tens of microns or less to hundreds of inches or more.

[0045] It will be understood by those skilled in the art that the micro LED display panel is not limited by the above structure and may include more or fewer components than those shown, or some components may be combined, or different components may be utilized.

[0046] It should be noted that relational terms such as "first" and "second" are used herein only to distinguish one entity or operation from another and do not require or imply an actual relationship or order between those entities or operations. Furthermore, the words "comprising," "having," "containing," and "including," as well as other similar forms, are intended to be equivalent in meaning and open-ended in that the one or more items following any one of these words are not intended to be an exhaustive listing of such one or more items, nor are they intended to be limited to only the listed one or more items.

[0047] As used herein, unless otherwise stated, the term "or" encompasses all possible combinations unless impracticable. For example, if it is stated that a database can include A or B, then the database can include A, or B, or A and B, unless otherwise stated or impracticable. As a second example, if it is stated that a database can include A, B, or C, then the database can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C, unless otherwise stated or impracticable.

[0048] It is understood by those skilled in the art that all or part of the steps for implementing the above-mentioned embodiments may be implemented by hardware, or may be implemented by a program instructing related hardware. The program may be stored in the above-mentioned flash memory, the above-mentioned conventional computer device, the above-mentioned central processing module, the above-mentioned adjustment module, etc.

[0049] The above description is only an embodiment of the present disclosure, and the present disclosure is not limited thereto. Any modifications, equivalent replacements and improvements made without departing from the concept and principle of the present disclosure shall fall within the protection scope of the present disclosure.

Claims

1. an IC backplane; at least three mesa structures stacked along a vertical axis, a first mesa structure formed on the IC backplane; a second mesa structure formed on the first mesa structure; and a third mesa structure formed on the second mesa structure; at least three mesa structures comprising: a top contact formed above the at least three mesa structures; Equipped with The second mesa structure comprises: a first connection layer; and a first reflective layer formed on the first connecting layer; a first bonding layer formed on the first reflective layer; a first light emitting layer formed on the first bonding layer, the first light emitting layer comprising a first semiconductor layer and a second semiconductor layer formed on the first semiconductor layer; a second connection layer formed on the first light-emitting layer; Equipped with the third mesa structure a second reflective layer formed on the second connecting layer; a second bonding layer formed on the second reflective layer; a second light emitting layer formed on the second bonding layer, the second light emitting layer comprising a third semiconductor layer and a fourth semiconductor layer formed on the third semiconductor layer; a third connection layer formed on the second light-emitting layer; Equipped with the first connection layer and the third connection layer are electrically connected to the IC backplane; the second connection layer is connected to the top contact; the first and fourth semiconductor layers have a first conductivity type, and the second and third semiconductor layers have a second conductivity type.

2. 10. The micro LED structure of claim 1, wherein the first mesa structure, the second mesa structure, and the third mesa structure form a first outline, a second outline, and a third outline, respectively, in plan view, the third outline being disposed within the second outline, and the second outline being disposed within the first outline.

3. The first mesa structure comprises: a third bonding layer formed on the IC backplane and electrically connected to the IC backplane; a third light-emitting layer formed on the first bonding layer, the third light-emitting layer comprising a fifth semiconductor layer and a sixth semiconductor layer formed on the fifth semiconductor layer, the fifth semiconductor layer having the first conductivity type, and the sixth semiconductor layer having the second conductivity type; a fourth connection layer formed on the first light-emitting layer and electrically connected to the top contact; Equipped with 10. The micro LED structure of claim 1, wherein the micro LED structure further comprises a first dielectric layer formed between the first connecting layer and the fourth connecting layer.

4. 4. The micro LED structure of claim 3, further comprising a first through via formed adjacent one or more of the first mesa structure, the second mesa structure, and the third mesa structure, the first through via electrically connecting to the second connection layer and the fourth connection layer.

5. 6. The micro LED structure of claim 5, further comprising a second through via and a third through via formed adjacent one or more of the first mesa structure, the second mesa structure, and the third mesa structure, the second through via connecting the first connection layer to the IC backplane and the third through via connecting the third connection layer to the IC backplane.

6. a sidewall of the first bonding layer aligned with a sidewall of the first light-emitting layer; a sidewall of the second bonding layer aligned with a sidewall of the second light-emitting layer; 10. The micro LED structure of claim 1.

7. Each of the first bonding layer and the second bonding layer is metal, composite metals, or Transparent conductive material 10. The micro LED structure of claim 1, comprising:

8. 8. The micro LED structure of claim 7, wherein the transparent conductive material is indium tin oxide (ITO), aluminum doped zinc oxide (AZO), or gallium doped zinc oxide (GZO).

9. 10. The micro LED structure of claim 1, wherein the first connecting layer, the second connecting layer, and the third connecting layer each comprise a transparent conductive material.

10. 10. The micro LED structure of claim 9, wherein the transparent conductive material is indium tin oxide (ITO).

11. 10. The micro LED structure of claim 1, wherein a sidewall of the first reflective layer is aligned with a sidewall of the first bonding layer.

12. 10. The micro LED structure of claim 1, wherein a sidewall of the second reflective layer is aligned with a sidewall of the second bonding layer.

13. the first reflective layer and the second reflective layer each comprise: Laminated permeable layer, metal omnidirectional reflection (ODR) layer, a stacked distributed Bragg reflector (DBR) layer, or high reflectivity metal 10. The micro LED structure of claim 1, comprising:

14. 10. The micro LED structure of claim 1, wherein each of the first and second reflective layers is electrically insulating.

15. 10. The micro LED structure of claim 1, wherein the first and second reflective layers, the first connecting layer, the second connecting layer, and the third connecting layer are transmissive.

16. 10. The micro LED structure of claim 1, wherein the first connecting layer, the second connecting layer, and the third connecting layer each comprise a transparent conductive material.

17. 10. The micro LED structure of claim 1, wherein the first and second conductivity types are P-type and N-type, respectively, or the first and second conductivity types are N-type and P-type, respectively.

18. further comprising a first sidewall connecting structure and a second sidewall connecting structure; the first sidewall connection structure is formed on the first connection layer and surrounds the sidewalls of the first reflective layer and the first bonding layer; the second sidewall connection structure is formed on the third connection layer and surrounds the sidewalls of the first layer, the second layer and the second bonding layer; 10. The micro LED structure of claim 1.

19. 20. The micro LED structure of claim 18, wherein the first sidewall connection structure and the second sidewall connection structure each comprise a transparent conductive material.

20. 20. The micro LED structure of claim 19, wherein the transparent conductive material is indium tin oxide (ITO).

21. 21. A full color micro LED panel comprising a micro LED array, said micro LED array comprising the micro LED structure according to any one of claims 1 to 20.

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