Miniature light-emitting device and manufacturing method thereof

Abstract

The invention relates to a miniature light-emitting device and a manufacturing method thereof, the miniature light-emitting device comprises at least one miniature light-emitting unit, the miniature light-emitting unit comprises a miniature light-emitting structure, and the miniature light-emitting structure comprises a step structure, the step structure comprises a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer and a third semiconductor layer which are stacked in sequence, the second semiconductor layer and the first semiconductor layer have different polarities, and the third semiconductor layer and the first semiconductor layer have the same polarity; the first light-emitting layer and the second light-emitting layer have different light-emitting colors, the step structure has a first step surface, and the first step surface is provided by the surface, deviating from the first light-emitting layer, of the second semiconductor layer in the step structure; the first electrode is arranged on the first step surface, and the second electrode is arranged on the periphery of the step structure and is electrically connected with the first semiconductor layer in the step structure, so that the manufacturing efficiency of the micro light-emitting diode full-color display device can be improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor light-emitting technologies, and particularly to a micro-light-emitting device and a manufacturing method thereof.

Background Art

[0002] Micro-LED (Micro-Light Emitting Diode) full-color display technology is a current hot topic. To achieve full-color display, the most common technical solution in the industry currently is to grow monochromatic epitaxial wafers for RGB (red, green, and blue) respectively, then perform chip processing and cut them into separate RGB (red, green, and blue) light-emitting chips, and then use a mass transfer technology to splice and combine the chips and weld them on a substrate to achieve RGB full-color display.

[0003] However, micro-light-emitting diode full-color display devices have the problem of low manufacturing efficiency.

Summary of the Invention

[0004] Embodiments of this application provide a micro-light-emitting device and a manufacturing method thereof to solve the problem of low manufacturing efficiency existing in micro-light-emitting diode full-color display devices in related technologies.

[0005] To solve the above problems, embodiments of this application provide a micro-light-emitting device. The micro-light-emitting device includes at least one micro-light-emitting unit. The micro-light-emitting unit includes a micro-light-emitting structure. The micro-light-emitting structure includes: a step structure, the step structure includes a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked. Among them, the second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, the first light-emitting layer and the second light-emitting layer have different light-emitting colors, and the step structure has a first step surface, and the first step surface is provided by the surface of the second semiconductor layer in the step structure facing away from the first light-emitting layer; a first electrode and a second electrode, the first electrode is disposed on the first step surface, and the second electrode is disposed on the periphery of the step structure and is electrically connected to the first semiconductor layer in the step structure.

[0006] Among them, the micro-light-emitting structure further includes: an electrical connection structure. The step structure and the second electrode are disposed on the same side of the electrical connection structure, and the surface of the first semiconductor layer in the step structure facing away from the first light-emitting layer faces the electrical connection structure. The second electrode is electrically connected to the first semiconductor layer in the step structure through the electrical connection structure.

[0007] Among them, the electrical connection structure includes an ohmic contact layer, and the ohmic contact layer forms ohmic contacts with the second electrode and the first semiconductor layer in the step structure respectively.

[0008] Among them, the micro light-emitting device further includes a driving substrate; and, in the micro light-emitting device, at least one micro light-emitting unit is a first light-emitting unit, and in the first light-emitting unit, the micro light-emitting structure of the first light-emitting unit is bonded to the driving substrate through a first electrode and a second electrode, and the third semiconductor layer of the micro light-emitting structure of the first light-emitting unit is electrically connected to the driving substrate.

[0009] Among them, in the first light-emitting unit, the micro light-emitting structure of the first light-emitting unit further includes a third electrode, the third electrode is disposed on the side of the third semiconductor layer in the step structure facing away from the second light-emitting layer, and the micro light-emitting structure of the first light-emitting unit is bonded to the driving substrate through the first electrode, the second electrode and the third electrode.

[0010] Among them, the micro light-emitting device further includes a driving substrate; and, in the micro light-emitting device, at least one micro light-emitting unit is a second light-emitting unit, the second light-emitting unit further includes a color conversion layer, and in the second light-emitting unit, the micro light-emitting structure of the second light-emitting unit is bonded to the driving substrate through a first electrode and a second electrode, the color conversion layer covers the micro light-emitting structure of the second light-emitting unit, and is configured to convert the light emitted by the first light-emitting layer into light of a target color, and the light of the target color, the light reflected by the first light-emitting layer and the light emitted by the second light-emitting layer are used to synthesize white light.

[0011] Among them, the second light-emitting unit further includes a light-blocking layer, and in the second light-emitting unit, the light-blocking layer covers the micro light-emitting structure of the second light-emitting unit, and an opening is provided on the light-blocking layer, the opening is located on the side of the micro light-emitting structure of the second light-emitting unit facing away from the driving substrate, and penetrates the light-blocking layer, and the color conversion layer fills the opening.

[0012] Among them, the micro light-emitting unit further includes a microlens, and in the micro light-emitting unit, the microlens of the micro light-emitting unit is disposed on the light-emitting side of the micro light-emitting structure of the micro light-emitting unit.

[0013] Among them, the first electrode includes a first electrode layer and a first conductive structure stacked in sequence along the stacking direction of the step structure; the second electrode includes a second electrode layer and a second conductive structure stacked in sequence along the stacking direction of the step structure; and, the micro light-emitting structure further includes: a first dielectric layer, the first dielectric layer covers the step structure, the first electrode layer and the second electrode layer, the first conductive structure penetrates the first dielectric layer and is electrically connected to the first electrode layer, the second conductive structure penetrates the first dielectric layer and is electrically connected to the second electrode layer, and the surface of the first dielectric layer facing away from the step structure, the first electrode layer and the second electrode layer is a flat surface.

[0014] To solve the above problems, an embodiment of the present application further provides a method for manufacturing a micro light-emitting device. The method for manufacturing the micro light-emitting device includes: providing an epitaxial stack, the epitaxial stack having a pixel region and a non-pixel region disposed around the pixel region, and including a substrate and a light-emitting stack. The light-emitting stack includes a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked. Among them, the second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, and the first light-emitting layer and the second light-emitting layer have different light-emitting colors; etching the light-emitting stack so that a portion of the light-emitting stack corresponding to the pixel region forms a stepped structure, and removing a portion of the light-emitting stack corresponding to the non-pixel region. Among them, the stepped structure has a first stepped surface, and the first stepped surface is provided by the surface of the second semiconductor layer in the stepped structure facing away from the first light-emitting layer; forming a first electrode on the first stepped surface of the stepped structure, and forming a second electrode in the non-pixel region around the stepped structure; forming an electrical connection structure on a side of the stepped structure facing away from the first electrode, and the electrical connection structure electrically connects the second electrode and the first semiconductor layer in the stepped structure to obtain a micro light-emitting structure including the stepped structure, the first electrode, the second electrode, and the electrical connection structure.

[0015] Among them, before the side of the stepped structure facing away from the first electrode, the method for manufacturing the micro light-emitting device further includes: forming a third electrode on a side of the third semiconductor layer in the stepped structure facing away from the second light-emitting layer.

[0016] Among them, before etching the light-emitting stack so that a portion of the light-emitting stack corresponding to the pixel region forms a stepped structure and removing a portion of the light-emitting stack corresponding to the non-pixel region, the method for manufacturing the micro light-emitting device further includes: forming a current diffusion layer on a side of the light-emitting stack facing away from the substrate; etching the light-emitting stack so that a portion of the light-emitting stack corresponding to the pixel region forms a stepped structure and removing a portion of the light-emitting stack corresponding to the non-pixel region, including: etching the light-emitting stack and the current diffusion layer so that a portion of the light-emitting stack corresponding to the pixel region forms a stepped structure, retaining the current diffusion layer on the surface of the third semiconductor layer in the stepped structure facing away from the second light-emitting layer, and removing a portion of the light-emitting stack corresponding to the non-pixel region; forming a third electrode on a side of the third semiconductor layer in the stepped structure facing away from the second light-emitting layer, including: forming a third electrode on a side of the current diffusion layer facing away from the third semiconductor layer in the stepped structure.

[0017] Among them, the epitaxial stack further includes a substrate, the light-emitting stack is disposed on one side of the substrate, and the first semiconductor layer, the first light-emitting layer, the second semiconductor layer, the second light-emitting layer, and the third semiconductor layer are sequentially stacked on the substrate; before forming an electrical connection structure on a side of the step structure away from the first electrode, the manufacturing method of the micro-light-emitting device further includes: removing the substrate to expose a first surface of the second electrode facing the substrate and a first surface of the first semiconductor layer in the step structure facing the substrate; forming an electrical connection structure on a side of the step structure away from the first electrode, including: forming an electrical connection structure on a first surface of the second electrode and a first surface of the first semiconductor layer in the step structure.

[0018] Among them, forming a first electrode on a first step surface of the step structure and forming a second electrode on a periphery of the step structure in a non-pixel region includes: forming a first electrode layer on the first step surface of the step structure, and forming a second electrode layer on a first surface of the substrate corresponding to the non-pixel region on the periphery of the step structure; forming a first dielectric layer, the first dielectric layer covering the substrate, the step structure, the first electrode layer, and the second electrode layer; forming a first conductive structure and a second conductive structure to obtain a first electrode including the first electrode layer and the first conductive structure and a second electrode including the second electrode layer and the second conductive structure, wherein the first conductive structure penetrates through the first dielectric layer and is electrically connected to the first electrode layer, the second conductive structure penetrates through the first dielectric layer and is electrically connected to the second electrode layer, and a surface of the first dielectric layer away from the substrate, the step structure, the first electrode layer, and the second electrode layer is a flat surface.

[0019] Among them, the manufacturing method of the micro-light-emitting device further includes: providing a driving substrate, the driving substrate including a substrate, a driving circuit, a second dielectric layer, a first driving-side conductive structure, and a second driving-side conductive structure, wherein the driving circuit is disposed on one side of the substrate, the second dielectric layer covers the substrate and the driving circuit, and a surface of the second dielectric layer away from the substrate and the driving circuit is a flat surface, the first driving-side conductive structure and the second driving-side conductive structure are disposed on a side of the driving circuit away from the substrate and both penetrate through the second dielectric layer and are both electrically connected to the driving circuit; and, before removing the substrate to expose a first surface of the second electrode facing the substrate and a first surface of the first semiconductor layer in the step structure facing the substrate, the manufacturing method of the micro-light-emitting device further includes: respectively bonding the first conductive structure and the second conductive structure to the first driving-side conductive structure and the second driving-side conductive structure in a corresponding manner, and bonding the first dielectric layer and the second dielectric layer in a corresponding manner to obtain a bonded structure; removing the substrate to expose a first surface of the second electrode facing the substrate and a first surface of the first semiconductor layer in the step structure facing the substrate, including: removing the substrate of the bonded structure to expose a first surface of the second electrode facing the substrate and a first surface of the first semiconductor layer in the step structure facing the substrate.

[0020] Among them, the number of pixel regions in the epitaxial stack is at least one, the non-pixel regions are arranged around each pixel region, and the number of micro-light-emitting structures obtained after forming the electrical connection structure on the side of the stepped structure facing away from the first electrode is at least one, and at least one micro-light-emitting structure corresponds one-to-one with at least one pixel region, and at least one of the at least one pixel regions is a first pixel region; and, after forming the electrical connection structure on the side of the stepped structure facing away from the first electrode, the manufacturing method of the micro-light-emitting device further includes: forming a color conversion layer, the color conversion layer covers the micro-light-emitting structure corresponding to the first pixel region, and is configured to convert the light emitted by the first light-emitting layer in the micro-light-emitting structure corresponding to the first pixel region into light of a target color, and the light of the target color, the light reflected by the first light-emitting layer, and the light emitted by the second light-emitting layer are used to synthesize white light.

[0021] Among them, forming the color conversion layer includes: forming a light-blocking layer, the light-blocking layer covers the micro-light-emitting structure corresponding to the first pixel region, and an opening is provided on the light-blocking layer, the opening is located on the light-emitting side of the micro-light-emitting structure corresponding to the first pixel region, and penetrates the light-blocking layer; forming the color conversion layer in the opening.

[0022] Among them, after forming the electrical connection structure on the side of the stepped structure facing away from the first electrode, the manufacturing method of the micro-light-emitting device further includes: forming a microlens on the light-emitting side of the micro-light-emitting structure.

[0023] The beneficial effects of the present application are as follows: The present application provides a micro-light-emitting device and a manufacturing method thereof. The micro-light-emitting device includes at least one micro-light-emitting unit, and the micro-light-emitting unit includes a micro-light-emitting structure. The micro-light-emitting structure includes a stepped structure, a first electrode, and a second electrode. Among them, the stepped structure includes a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked. The second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, the first light-emitting layer and the second light-emitting layer have different emission colors, and the stepped structure has a first stepped surface, which is provided by the surface of the second semiconductor layer in the stepped structure facing away from the first light-emitting layer. The first electrode is disposed on the first stepped surface, and the second electrode is disposed on the periphery of the stepped structure and is electrically connected to the first semiconductor layer in the stepped structure. In this way, by adjusting the epitaxial growth process, structural design, and micro-nano processing, a micro-light-emitting structure capable of simultaneously emitting two colors of light (for example, blue light and green light) can be obtained. Moreover, in the micro-light-emitting structure capable of simultaneously emitting two colors of light provided by the present application, one electrode is disposed on the periphery of the stepped structure instead of on the stepped surface of the stepped structure, thereby reducing the number of stepped surfaces required to be formed when etching the micro-light-emitting diode epitaxial wafer, which is beneficial to reducing the process difficulty of forming the stepped structure by etching the micro-light-emitting diode epitaxial wafer and reducing the yield risk that may be brought by the process of forming the stepped structure by etching the micro-light-emitting diode epitaxial wafer. Therefore, the manufacturing efficiency and yield of the dual-color micro-light-emitting diode chip can be improved.

[0024] In addition, the micro-light-emitting structure capable of simultaneously emitting two colors of light provided by the present application can achieve full-color display either by being paired with a monochromatic micro-light-emitting diode chip having other emission colors (for example, red) or by being paired with quantum dots of other colors. In this way, compared with the solution of separately manufacturing red, green, and blue LEDs and separately performing massive transfer to achieve full-color display, the solution of achieving full-color display by pairing the micro-light-emitting structure capable of simultaneously emitting two colors of light provided by the present application with a monochromatic micro-light-emitting diode chip having other emission colors can reduce the number of massive transfer times. Compared with the solution of achieving full-color display by pairing a monochromatic micro-light-emitting diode chip with two other colors of quantum dots, the solution of achieving full-color display by pairing the micro-light-emitting structure capable of simultaneously emitting two colors of light provided by the present application with one other color of quantum dots can reduce the number of quantum dot printing times. Therefore, by using the micro-light-emitting structure capable of simultaneously emitting two colors of light provided by the present application to achieve full-color display, the manufacturing efficiency and yield of the micro-light-emitting diode full-color display device can be improved.

Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 is a schematic cross-sectional structure diagram of a micro light-emitting device provided in an embodiment of the present application;

[0027] Figure 2 is another schematic cross-sectional structure diagram of a micro-light-emitting device provided in an embodiment of the present application;

[0028] Figure 3 is another schematic cross-sectional structure diagram of a micro-light-emitting device provided in an embodiment of the present application;

[0029] Figure 4 is another schematic cross-sectional structure diagram of a micro-light-emitting device provided in an embodiment of the present application;

[0030] Figure 5 is another schematic cross-sectional structure diagram of a micro-light-emitting device provided in an embodiment of the present application;

[0031] Figure 6 is another schematic cross-sectional structure diagram of a micro-light-emitting device provided in an embodiment of the present application;

[0032] Figure 7 It is a schematic diagram of a process for manufacturing a micro-light-emitting device provided in an embodiment of the present application;

[0033] Figure 8 is a schematic diagram of the cross-sectional structure of an epitaxial stack provided in an embodiment of the present application;

[0034] Figure 9 is a schematic diagram of the cross-sectional structure after step S12 is completed provided in an embodiment of the present application;

[0035] Figure 10 It is a schematic diagram of the cross-sectional structure after a current diffusion layer is formed on a side of the light-emitting stack facing away from the substrate provided in an embodiment of the present application;

[0036] Figure 11 is another cross-sectional structural schematic diagram after step S12 provided in an embodiment of the present application is completed;

[0037] Figure 12 is a schematic diagram of the cross-sectional structure after step S13 provided in the embodiment of the present application is completed;

[0038] Figure 13 is a schematic cross-sectional structure diagram of a driving substrate provided in an embodiment of the present application;

[0039] Figure 14 It is a schematic cross-sectional structure diagram after respectively and correspondingly bonding a first conductive structure and a second conductive structure to a first driving-side conductive structure and a second driving-side conductive structure, and correspondingly bonding a first dielectric layer and a second dielectric layer, provided by an embodiment of the present application;

[0040] Figure 15 It is a schematic cross-sectional structure diagram after removing a substrate, provided by an embodiment of the present application;

[0041] Figure 16 It is a schematic cross-sectional structure diagram after step S14 provided by an embodiment of the present application is completed.

Specific Embodiment

[0042] Next, with reference to the accompanying drawings and embodiments, the embodiments of the present application will be further described in detail. It should be specifically noted that the following embodiments are only used to illustrate the embodiments of the present application, but do not limit the scope of the embodiments of the present application. Similarly, the following embodiments are only some embodiments of the embodiments of the present application rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the embodiments of the present application.

[0043] When describing the structure of a component, when a layer or a region is referred to as being "on" or "above" another layer or another region, it may mean directly on the other layer or another region, or there may be other layers or regions between it and the other layer or another region. And if the component is flipped, this layer or region will be "under" or "below" the other layer or another region. In addition, the features, structures or characteristics described below can be combined in one or more embodiments in any suitable manner.

[0044] In addition, the directional terms mentioned in the embodiments of the present application, such as [up], [down], [front], [back], [left], [right], [inside], [outside], [side], etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are for explaining and understanding the embodiments of the present application, rather than for limiting the embodiments of the present application. In each of the drawings, units with similar structures are denoted by the same reference numerals. For clarity, the various parts in the drawings are not drawn to scale. In addition, some related parts may not be shown in the drawings.

[0045] Micro-LED full-color display technology is a hot topic at present. There are different technical solutions on the market to achieve full-color display, such as mass transfer, three-color module optical synthesis, quantum dot color conversion, in-situ epitaxial growth, three-color stacking bonding, etc. These solutions have their own characteristics, among which the first three technical solutions are currently the most mentioned, especially the mass transfer and quantum dot color conversion solutions. Many companies have conducted research and layout on these two technical routes, which also reflects the relative maturity and recognition of the technology from the side.

[0046] The mass transfer solution involves the precise positioning and transfer of a large number of tiny chips, which requires high-precision equipment and control technology. During the transfer process, due to the large number of chips, even a very small proportion of failures will lead to a significant decrease in the overall yield. It takes a long time to transfer a large number of chips, and the production efficiency is low. If failures or defects occur during the transfer process, it is very difficult and time-consuming to repair these defects, which increases the complexity of production.

[0047] The key to the quantum dot color conversion solution is quantum dots, which have significant advantages in the display field, such as high color purity, wide color gamut, high brightness and contrast, but at the same time it also has some disadvantages, such as toxicity issues, manufacturing complexity, uniformity and consistency, and reliability issues.

[0048] In addition, there are related technologies that achieve full-color display by directly growing blue-green or even red, green and blue epitaxial layers in the epitaxial stage, or by vertically stacking and bonding light-emitting chips of three luminous colors to achieve full-color display. The starting points of these solutions are very novel, but the difficulties in actual production are obvious. The unstable processes related to these solutions may bring yield risks and luminous efficiency problems.

[0049] In view of the above problems, an embodiment of the present application provides a micro light-emitting device and a manufacturing method thereof. The micro light-emitting device includes at least one micro light-emitting unit, and the micro light-emitting unit includes a micro light-emitting structure. The micro light-emitting structure includes a step structure, a first electrode, and a second electrode. Specifically, the step structure includes a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked. Among them, the second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, the first light-emitting layer and the second light-emitting layer have different light-emitting colors, and the step structure has a first step surface, and the first step surface is provided by the surface of the second semiconductor layer in the step structure facing away from the first light-emitting layer. The first electrode is disposed on the first step surface, and the second electrode is disposed on the periphery of the step structure and is electrically connected to the first semiconductor layer in the step structure. In this way, by adjusting the epitaxial growth process, structural design, and micro-nano processing, a micro light-emitting structure that can emit two colors of light simultaneously (for example, blue light and green light) can be obtained. Moreover, in the micro light-emitting structure provided by the present application that can emit two colors of light simultaneously, one electrode is disposed on the periphery of the step structure instead of on the step surface of the step structure, so that the number of step surfaces required for etching the micro light-emitting diode epitaxial wafer can be reduced, which is beneficial to reducing the process difficulty of forming the step structure by etching the micro light-emitting diode epitaxial wafer and reducing the yield risk that may be brought by the process of forming the step structure by etching the micro light-emitting diode epitaxial wafer. Therefore, the manufacturing efficiency and yield of the dual-color micro light-emitting diode chip can be improved.

[0050] Moreover, the micro light-emitting structure provided by the present application that can emit two colors of light simultaneously can achieve full-color display either by being paired with a monochromatic micro light-emitting diode chip with other light-emitting colors (for example, red) or by being paired with quantum dots of other colors. In this way, compared with the solution of separately manufacturing red, green, and blue LEDs and separately performing massive transfer to achieve full-color display, the solution of using the micro light-emitting structure provided by the present application that can emit two colors of light simultaneously and being paired with a monochromatic micro light-emitting diode chip with other light-emitting colors to achieve full-color display can reduce the number of massive transfer times by one. Compared with the solution of using a monochromatic micro light-emitting diode chip and being paired with two other colors of quantum dots to achieve full-color display, the solution of using the micro light-emitting structure provided by the present application that can emit two colors of light simultaneously and being paired with one other color of quantum dots to achieve full-color display can reduce the number of quantum dot printing times by one. Therefore, by using the micro light-emitting structure provided by the present application that can emit two colors of light simultaneously to achieve full-color display, the manufacturing efficiency and yield of the micro light-emitting diode full-color display device can be improved.

[0051] The following will be described in detail with specific embodiments. It should be noted that the embodiments of the present application can be presented in various forms, and some examples will be described below.

[0052] Please refer to Figure 1 , Figure 1 which is a schematic cross-sectional structure diagram of a micro light-emitting device provided by an embodiment of the present application. As shown in Figure 1 , the micro light-emitting device 1 includes a micro light-emitting unit 10. Specifically, the micro light-emitting unit 10 includes a micro light-emitting structure 100, and the micro light-emitting structure 100 includes a stepped structure 100A. The stepped structure 100A includes a first semiconductor layer 101, a first light-emitting layer 102, a second semiconductor layer 103, a second light-emitting layer 104, and a third semiconductor layer 105 that are sequentially stacked. Among them, the second semiconductor layer 103 and the first semiconductor layer 101 have different polarities, the third semiconductor layer 105 and the first semiconductor layer 101 have the same polarity, the first light-emitting layer 102 and the second light-emitting layer 104 have different light-emitting colors, and the stepped structure 100A has a first stepped surface F1, and the first stepped surface F1 is provided by the surface (i.e., the upper surface) of the second semiconductor layer 103 in the stepped structure 100A that faces away from the first light-emitting layer 102.

[0053] Specifically, the micro light-emitting structure 100 further includes a first electrode 106 and a second electrode 107. Among them, the first electrode 106 is disposed on the first stepped surface F1 of the stepped structure 100A and is electrically connected to the second semiconductor layer 103. The second electrode 107 is disposed around the stepped structure 100A and is electrically connected to the first semiconductor layer 101 in the stepped structure 100A. And, in specific implementation, the height of the first electrode 107 in the stacking direction (i.e., Figure 1 the upward direction from bottom to top in Figure 1 ) of the stepped structure 100A and the height of the second electrode in the stacking direction of the stepped structure 100A can both be greater than the height of the third semiconductor layer 105 in the stacking direction of the stepped structure 100A, so as to ensure that the micro light-emitting structure 100 can be bonded to other structures (such as a driving substrate) through the first electrode 106 and the second electrode 107.

[0054] In this embodiment, in the above-mentioned micro light-emitting structure 100, the stepped structure 100A has two PN structures with different light-emitting colors that are sequentially stacked along the stacking direction (i.e., Figure 1 the upward direction from bottom to top in Figure 1 ) of the stepped structure 100A, denoted as: a first PN structure and a second PN structure. Specifically, the first PN structure and the second PN structure share the first electrode 106, and the first PN structure at least includes the first semiconductor layer 101 and the first light-emitting layer 102, and the second PN structure at least includes the second light-emitting layer 104 and the third semiconductor layer 105. And, the second semiconductor layer 103 in the stepped structure 100A can belong to any one of the first PN structure and the second PN structure; or, the second semiconductor layer 103 in the stepped structure 100A can belong to both the first PN structure and the second PN structure.

[0055] It should be noted that in this embodiment, only the example where the second semiconductor layer 103 is provided between the first light-emitting layer 102 and the third light-emitting layer 104 in the step structure 100A is given. In other embodiments, other structures (such as another semiconductor layer with the same polarity as the second semiconductor layer 103) may also be provided between the first light-emitting layer 102 and the third light-emitting layer 104 in the step structure 100A. Moreover, this embodiment does not limit the specific structure provided between the first light-emitting layer 102 and the third light-emitting layer 104 in the step structure 100A. The structure provided between the first light-emitting layer 102 and the third light-emitting layer 104 in the step structure 100A can enable the step structure 100A to have two PN structures stacked in sequence along the stacking direction of the step structure 100A (i.e., Figure 1 the bottom-to-top direction in

[0056] In some embodiments, as Figure 1 shown, the above-mentioned micro light-emitting structure 100 may further include a third electrode 108. The third electrode 108 is disposed on the side of the third semiconductor layer 105 in the step structure 100A facing away from the second light-emitting layer 104 and is electrically connected to the third semiconductor layer 105. In this way, it can be realized that the two PN structures of the step structure 100A share the first electrode 106 and respectively have independent second electrodes 107 and third electrodes 108.

[0057] Specifically, in the above embodiment where the above-mentioned micro light-emitting structure 100 further includes a third electrode 108, as Figure 1 shown, the above-mentioned micro light-emitting structure 100 may further include a current diffusion layer 109. The current diffusion layer 109 is disposed between the third electrode 108 and the third semiconductor layer 105 in the step structure 100A. Moreover, the current diffusion layer 109 can very evenly spread the current to the entire third semiconductor layer 105 (such as a P-type gallium nitride layer), thereby effectively improving the light-emitting efficiency of the above-mentioned second light-emitting layer 104.

[0058] And, in specific implementation, the above-mentioned current diffusion layer 109 can be obtained by evaporating multiple layers of metals (such as titanium Ti, aluminum Al, gold Au, platinum Pt, or nickel Ni, etc.) or semiconductor oxides (such as indium tin oxide ITO or zinc oxide ZnO, etc.) on the surface of the third semiconductor layer 105 in the step structure 100A facing away from the second light-emitting layer 104 to form current conduction.

[0059] In this embodiment, as Figure 1 shown, the above-mentioned first electrode 106 is in the stacking direction of the step structure 100A (i.e., Figure 1The height in the upward direction can be equal to the height of the second electrode 107 in the stacking direction of the stepped structure 100A. Further, in the above embodiment where the micro-light emitting structure 100 further includes a third electrode 108, as Figure 1 shown, the height of the third electrode 108 in the stacking direction of the stepped structure 100A can be equal to the height of the first electrode 106 and the height of the second electrode 107 in the stacking direction of the stepped structure 100A. Thus, it is beneficial to reduce the process difficulty of bonding the micro-light emitting structure 100 to other structures (such as a driving substrate) through the first electrode 106, the second electrode 107, and the third electrode 108.

[0060] It should be noted that, in this embodiment, the micro-light emitting structure 100 can emit at most two colors of light simultaneously. That is, the micro-light emitting structure 100 can have two light emitting states, namely: a state of emitting only one color of light (such as blue light); and a state of emitting two colors of light simultaneously (such as blue light and green light).

[0061] Further, in specific implementation, during the use of the micro-light emitting structure 100, by respectively providing corresponding driving signals (such as driving voltages) to the first electrode 106 and the second electrode 107, and not providing a corresponding driving signal to the third semiconductor layer 105 (or the third electrode 108), it is possible to drive only the first light emitting layer 102 to emit light and not drive the second light emitting layer 104 to emit light, thereby realizing that the micro-light emitting structure 100 emits only one color of light; or, by respectively providing corresponding driving signals to the first electrode 106, the second electrode 107, and the third semiconductor layer 105 (or the third electrode 108), it is possible to drive both the first light emitting layer 102 and the second light emitting layer 104 to emit light simultaneously, thereby realizing that the micro-light emitting structure 100 emits two colors of light simultaneously.

[0062] It can be understood that the micro-light emitting structure 100 may include the third electrode 108 (as Figure 1 shown), or may not include the third electrode 108 (as Figure 2 shown). Further, during the use of the micro-light emitting structure 100, when it is necessary to drive the second light emitting layer 104 to emit light, in the case where the micro-light emitting structure 100 includes the third electrode 108, as Figure 1 shown, it is possible to drive the second light emitting layer 104 to emit light by directly providing a corresponding driving signal to the third electrode 108; while in the case where the micro-light emitting structure 100 does not include the third electrode 108, as Figure 2As shown, the driving of the second light-emitting layer 104 to emit light can be achieved by directly providing a corresponding driving signal to the above-mentioned third semiconductor layer 105 (or the above-mentioned current diffusion layer 109).

[0063] In some embodiments, as Figure 1 shown, the above-mentioned micro light-emitting structure 100 may further include an electrical connection structure 110, and the second electrode 107 is electrically connected to the first semiconductor layer 101 in the step structure 100A through the electrical connection structure 110. Specifically, as Figure 1 shown, the step structure 100A and the second electrode 107 may be disposed on the same side of the electrical connection structure 110, and the surface of the first semiconductor layer 101 in the step structure 100A facing away from the first light-emitting layer 102 may be arranged facing the electrical connection structure 110. Moreover, in specific implementation, as Figure 1 shown, the surface of the first semiconductor layer 101 in the step structure 100A facing away from the first light-emitting layer 102 may be in contact with the electrical connection structure 100A, the second electrode 107 may be in contact with the electrical connection structure 110, and be spaced apart from the sidewall of the step structure 100A, so as to realize the electrical connection between the second electrode 107 and the first semiconductor layer 101 in the step structure 100A through the electrical connection structure 110, and avoid the electrical connection between the second electrode 107 and other film layer structures in the step structure 100A except the first semiconductor layer 101.

[0064] It should be noted that the above-mentioned micro light-emitting structure 100 may include the above-mentioned electrical connection structure 110 (as Figure 1 shown), or may not include the above-mentioned electrical connection structure 110. And in the case where the above-mentioned micro light-emitting structure 100 does not include the above-mentioned electrical connection structure 110, the second electrode 107 may be in contact with the sidewall of the first semiconductor layer 101, and be spaced apart from other film layer structures in the step structure 100A except the first semiconductor layer 101, so as to ensure that the second electrode 107 is only electrically connected to the first semiconductor layer 101 in the step structure 100A, and is not electrically connected to other film layer structures in the step structure 100A except the first semiconductor layer 101.

[0065] It should be noted that the present embodiment does not limit the specific structure, setting position and material of the above-mentioned electrical connection structure 110, and the above-mentioned electrical connection structure 110 can achieve the electrical connection between the second electrode 107 and the first semiconductor layer 101 in the step structure 100A.

[0066] In some specific embodiments, as Figure 1As shown, the electrical connection structure 110 may include an ohmic contact layer 110, for example, the ohmic contact layer 110. Moreover, the ohmic contact layer 110 forms ohmic contacts with the second electrode 107 and the first semiconductor layer 101 in the step structure 100A, respectively, so that the ohmic contact layer 110 can evenly distribute the current to the entire first semiconductor layer 101 (for example, the P-type gallium nitride layer), so as to effectively improve the luminous efficiency of the first light-emitting layer 102.

[0067] Exemplarily, the electrical connection structure 110 (or the ohmic contact layer 110) may be light-transmitting, for example, may be transparent, and its material may include a light-transmitting semiconductor oxide (for example, indium tin oxide ITO or zinc oxide ZnO, etc.), thereby reducing the influence of the electrical connection structure 110 (or the ohmic contact layer 110) on the light extraction efficiency of the micro-light-emitting structure 100.

[0068] In this embodiment, in the above-mentioned micro-light emitting structure 100, the first light emitting layer 102 and the second light emitting layer 104 may be quantum well layers, for example, may be indium gallium nitride quantum well layers, or may be indium gallium nitride / gallium nitride multi-quantum well layers. The first semiconductor layer 101 and the third semiconductor layer 105 may be one of an N-type semiconductor layer and a P-type semiconductor layer, and the second semiconductor layer 103 may be the other of an N-type semiconductor layer and a P-type semiconductor layer, wherein the N-type semiconductor layer may be specifically an N-type gallium nitride layer or an N-type gallium arsenide layer, and the P-type semiconductor layer may be specifically a P-type gallium nitride layer or a P-type aluminum gallium nitride layer.

[0069] In some examples, the light color of one of the first light-emitting layer 102 and the second light-emitting layer 104 may be blue, and the light color of the other of the first light-emitting layer 102 and the second light-emitting layer 104 may be green. Exemplarily, the light color of the first light-emitting layer 102 may be blue, and the light color of the second light-emitting layer 104 may be green, so that during the use of the micro-light-emitting structure 100, it can be ensured that the blue light emitted by the first light-emitting layer 102 can be emitted to the light-emitting side of the micro-light-emitting structure 100 (that is, the side of the first light-emitting layer 102 away from the second light-emitting layer 104) without passing through the second light-emitting layer 104, thereby ensuring the brightness of the blue light, reducing the brightness difference between the blue light and the green light simultaneously emitted by the micro-light-emitting structure 100, and improving the full-color display effect.

[0070] In some examples, the above-mentioned first semiconductor layer 101 and third semiconductor layer 105 may both be P-type semiconductor layers, and the above-mentioned second semiconductor layer 103 may be an N-type semiconductor layer. Correspondingly, the above-mentioned first electrode 106 may be an N-type electrode electrically connected to the N-type semiconductor layer, and the above-mentioned second electrode 107 and third electrode 108 may be P-type electrodes electrically connected to different P-type semiconductor layers respectively, so as to realize that the two PN structures with different light-emitting colors in the step structure 100A of the above-mentioned micro-light-emitting structure 100 share the same N-type electrode and each has an independent P-type electrode.

[0071] In other examples, the above-mentioned first semiconductor layer 101 and third semiconductor layer 105 may both be N-type semiconductor layers, and the above-mentioned second semiconductor layer 103 may be a P-type semiconductor layer. Correspondingly, the above-mentioned first electrode 106 may be a P-type electrode electrically connected to the P-type semiconductor layer, and the above-mentioned second electrode 107 and third electrode 108 may be N-type electrodes electrically connected to different N-type semiconductor layers respectively, so as to realize that the two PN structures with different light-emitting colors in the step structure 100A of the above-mentioned micro-light-emitting structure 100 share the same P-type electrode and each has an independent N-type electrode.

[0072] Moreover, during specific implementation, as Figure 1 shown, the above-mentioned first electrode 106 and second electrode 107 may be located on opposite sides of the above-mentioned micro-light-emitting structure 100 respectively (for example, Figure 1 the left side and the right side shown in Figure 1 ). And, in the above-mentioned embodiment where the above-mentioned micro-light-emitting structure 100 further includes a third electrode 108, as

[0073] shown, the above-mentioned third electrode 108 may be located between the above-mentioned first electrode 106 and second electrode 107 and be disposed close to the above-mentioned second electrode 107. In this way, during the use of the above-mentioned micro-light-emitting structure 100, the current diffusion between the P-type electrode and the N-type electrode can be made more uniform, so as to improve the current crowding effect of the micro-light-emitting structure 100, thereby reducing the damage risk of the micro-light-emitting structure 100, improving the reliability of the micro-light-emitting structure 100, and enhancing the electrical performance of the micro-light-emitting structure 100.

[0073] In this embodiment, as Figure 1 shown, the above-mentioned first electrode 106 may include a first electrode layer 1061, and the above-mentioned second electrode 107 may include a second electrode layer 1071. And, in the above-mentioned embodiment where the above-mentioned micro-light-emitting structure 100 further includes a third electrode 108, as Figure 1 shown, the above-mentioned third electrode 108 may include a third electrode layer 1081.

[0074] In some examples, the material of the above-mentioned first electrode layer 1061 may include at least one of metal materials such as titanium (Ti), gold (Au), platinum (Pt), nickel (Ni), and aluminum (Al). The material of the above-mentioned second electrode layer 1071 may include at least one of metal materials such as titanium (Ti), gold (Au), platinum (Pt), nickel (Ni), and aluminum (Al). The material of the above-mentioned third electrode layer 1081 may include at least one of metal materials such as titanium (Ti), gold (Au), platinum (Pt), nickel (Ni), and aluminum (Al). Moreover, in specific implementation, the above-mentioned first electrode layer 1061, second electrode layer 1071, and third electrode layer 1081 may have the same material and may be formed synchronously.

[0075] In some embodiments, as Figure 1 shown, the above-mentioned micro-light-emitting structure 100 may further include a first dielectric layer 111. The first dielectric layer 111 covers the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071, and may fill the upper surface of the stepped structure 100A, so that the surface (i.e., the upper surface) of the first dielectric layer 111 facing away from the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071 is a flat surface. Moreover, in the above-mentioned embodiment where the micro-light-emitting structure 100 further includes a third electrode 108 and the third electrode 108 includes the third electrode layer 1081, the above-mentioned first dielectric layer 111 may further cover the third electrode layer 1081. In this way, the first dielectric layer 111 can effectively block the erosion of external water and oxygen on the stepped structure 100A, the first electrode layer 1061, the second electrode layer 1071, and the third electrode layer 1081, thereby improving the reliability of the micro-light-emitting structure 100.

[0076] Specifically, the material of the above-mentioned first dielectric layer 111 may include insulating materials such as silicon oxide, silicon nitride, and / or aluminum oxide. In some examples, the above-mentioned first dielectric layer 111 may be a single-layer structure. For example, it may be a silicon oxide layer. In other examples, the above-mentioned first dielectric layer 111 may also be a stacked structure. For example, it may be a stacked structure of silicon nitride / silicon oxide, and the outermost layer of the stacked structure facing away from the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071 may be a silicon oxide layer.

[0077] In some specific embodiments, as Figure 1 shown, the above-mentioned first electrode 106 may further include a first conductive structure 1062. The first electrode layer 1061 and the first conductive structure 1062 are along the stacking direction of the stepped structure 100A (i.e., Figure 1They are stacked in sequence in the upward direction (from bottom to top) in [description], and the first conductive structure 1062 penetrates through the first dielectric layer 111 and is electrically connected to the first electrode layer 1061. The second electrode 107 may further include a second conductive structure 1072. The second electrode layer 1071 and the second conductive structure 1072 are stacked in sequence along the stacking direction of the stepped structure 100A. And the second conductive structure 1072 penetrates through the first dielectric layer 111 and is electrically connected to the second electrode layer 1071.

[0078] And the first conductive structure 1062 is in the stacking direction of the stepped structure 100A (i.e., Figure 1 the upward direction from bottom to top in [description]), and the height of the first conductive structure 1062 in the stacking direction of the stepped structure 100A may be equal to the height of the second conductive structure 1072 in the stacking direction of the stepped structure 100A. That is, the upper surfaces of the first conductive structure 1062 and the second conductive structure 1072 may be located on the same horizontal plane.

[0079] And in specific implementation, as Figure 1 shown, the first electrode 106 may further include a first barrier layer 1063. The first barrier layer 1063 is disposed between the first electrode layer 1061 and the first conductive structure 1062 to prevent the conductive material (such as metals like copper) in the first conductive structure 1062 from migrating into the stepped structure 100A through the first electrode layer 1061, thereby reducing the influence of the first conductive structure 1062 on the light-emitting efficiency of the micro-light-emitting structure 100.

[0080] And in specific implementation, as Figure 1 shown, the second electrode 107 may further include a second barrier layer 1073. The second barrier layer 1073 is disposed between the second electrode layer 1071 and the second conductive structure 1072 to prevent the conductive material (such as metals like copper) in the second conductive structure 1072 from migrating into the stepped structure 100A through the second electrode layer 1071, thereby reducing the influence of the second conductive structure 1072 on the light-emitting efficiency of the micro-light-emitting structure 100.

[0081] Specifically, in the above embodiment where the micro-light-emitting structure 100 further includes a third electrode 108 and the third electrode 108 includes a third electrode layer 1081, as Figure 1 shown, the third electrode 108 may further include a third conductive structure 1082. The third electrode layer 1081 and the third conductive structure 1082 are stacked in sequence along the stacking direction of the stepped structure 100A. And the first dielectric layer 111 covers the third electrode layer 1081, the third conductive structure 1082 penetrates through the first dielectric layer 111 and is electrically connected to the third electrode layer 1081.

[0082] And the third conductive structure 1082 is in the stacking direction of the stepped structure 100A (i.e.,Figure 1 The height in the upward direction may be equal to the height of the first conductive structure 1062 in the stacking direction of the stepped structure 100A and the height of the second conductive structure 1072 in the stacking direction of the stepped structure 100A. That is, the upper surface of the third conductive structure 1082 may be on the same horizontal plane as the upper surface of the first conductive structure 1062 and the second conductive structure 1072.

[0083] And, in specific implementation, as Figure 1 shown, the third electrode 108 may further include a third barrier layer 1083 disposed between the third electrode layer 1081 and the third conductive structure 1082 to prevent the conductive material (such as metals like copper) in the third conductive structure 1082 from migrating into the stepped structure 100A through the third electrode layer 1081, thereby reducing the influence of the third conductive structure 1082 on the light emission efficiency of the micro light-emitting structure 100.

[0084] In some examples, the material of the first conductive structure 1062 may include metals such as Cu (copper), Ag (silver), Au (gold), and Ni (nickel). The material of the second conductive structure 1072 may include metals such as Cu (copper), Ag (silver), Au (gold), and Ni (nickel). The material of the third conductive structure 1082 may include metals such as Cu (copper), Ag (silver), Au (gold), and Ni (nickel). And, in specific implementation, the first conductive structure 1062, the second conductive structure 1072, and the third conductive structure 1082 may have the same material. For example, they may all be copper and may be formed synchronously.

[0085] In some examples, the material of the first barrier layer 1063 may include conductive materials such as tantalum nitride (TaN) and / or titanium nitride (TiN). The material of the second barrier layer 1073 may include conductive materials such as tantalum nitride (TaN) and / or titanium nitride (TiN). The material of the third barrier layer 1083 may include conductive materials such as tantalum nitride (TaN) and / or titanium nitride (TiN). And, in specific implementation, the first barrier layer 1063, the second barrier layer 1073, and the third barrier layer 1083 may have the same material and may be formed synchronously.

[0086] And, it should be noted that in the micro light-emitting structure 100, the third electrode 108 may include the third electrode layer 1081, the third barrier layer 1083, and the third conductive structure 1082 stacked in sequence along the stacking direction of the stepped structure 100 (i.e., Figure 1 the upward direction in Figure 1as shown), or may only include the above-mentioned third electrode layer 1081, or may only include the above-mentioned third electrode layer 1081 and the third barrier layer 1083 stacked in sequence along the stacking direction of the step structure 100 (as Figure 3 shown).

[0087] In the above embodiment, the above-mentioned micro light-emitting device 1 may include one or more micro light-emitting units 10.

[0088] In some examples, as Figure 1 shown, the above-mentioned micro light-emitting device 1 may include one micro light-emitting unit 10. For example, it may specifically be the micro light-emitting unit 10.

[0089] In other examples, as Figure 4 shown, the above-mentioned micro light-emitting structure 10 may include a plurality of micro light-emitting units 10. The plurality of micro light-emitting units 10 may be arranged in an array, and the first dielectric layers 111 of the plurality of micro light-emitting units 10 may be connected into an integral structure. The step structures 100A of the plurality of micro light-emitting units 10 may be arranged at intervals. The second electrodes 107 of the plurality of micro light-emitting units 10 may be arranged at intervals. The electrical connection structures 110 of the plurality of micro light-emitting units 10 may be arranged at intervals.

[0090] In some embodiments, as Figure 4 shown, the above-mentioned micro light-emitting device 1 may further include a driving substrate 200. And, in the micro light-emitting device 1, at least one micro light-emitting unit 10 may be a first light-emitting unit 10A. Specifically, in the first light-emitting unit 10A, the micro light-emitting structure 100 of the first light-emitting unit 10A is bonded to the driving substrate 200 through the first electrode 106 and the second electrode 107. The third semiconductor layer 105 of the micro light-emitting structure 100 of the first light-emitting unit 10A is electrically connected to the driving substrate 200, so that the driving substrate 200 can drive the micro light-emitting structure 100 in the first light-emitting unit 10A to emit two colors of light simultaneously to realize the display function of the above-mentioned micro light-emitting device 1.

[0091] Specifically, as Figure 4 shown, in the above-mentioned first light-emitting unit 10A, the micro light-emitting structure 100 of the first light-emitting unit 10A may include the above-mentioned third electrode 108, and the micro light-emitting structure 100 of the first light-emitting unit 10A may specifically be bonded to the driving substrate 200 through the first electrode 106, the second electrode 107, and the third electrode 108.

[0092] Specifically, as Figure 4As shown, in the above-mentioned first light-emitting unit 10A, the outermost layer of the micro light-emitting structure 100 of the first light-emitting unit 10A facing away from the driving substrate 200 can be an electrical connection structure 110, and the electrical connection structure 110 can be light-transmissive. For example, specifically, it can be transparent, so as to avoid the electrical connection structure 110 blocking the light emitted by the first light-emitting layer 102 and the second light-emitting layer 104, thereby improving the light extraction efficiency of the above-mentioned micro light-emitting device 1.

[0093] In some embodiments, as Figure 4 As shown, in the above-mentioned micro light-emitting device 1, at least one micro light-emitting unit 10 can be a second light-emitting unit 10B, and the second light-emitting unit 10B further includes a color conversion layer 114. Specifically, in the second light-emitting unit 10B, the micro light-emitting structure 100 of the second light-emitting unit 10B is bonded to the driving substrate 200 through the first electrode 106 and the second electrode 107. The third semiconductor layer 105 of the micro light-emitting structure 100 of the second light-emitting unit 10B is electrically connected or not electrically connected to the driving substrate 200, and the color conversion layer 114 covers the micro light-emitting structure 100 of the second light-emitting unit 10B and is configured to convert the light emitted by the first light-emitting layer 102 into light of a target color, and the light of the target color, the light reflected by the first light-emitting layer 102, and the light emitted by the second light-emitting layer 104 are used to synthesize white light. Specifically, the above-mentioned target color, the light-emitting color of the above-mentioned first light-emitting layer 102, and the light-emitting color of the above-mentioned second light-emitting layer 104 can together form the three primary colors to achieve full-color display of the above-mentioned micro light-emitting device 1.

[0094] Exemplarily, the light-emitting color of the above-mentioned first light-emitting layer 102 can be blue, the light-emitting color of the above-mentioned second light-emitting layer 104 can be green, and the above-mentioned target color can be red, so as to achieve the red, green, and blue three-color display of the above-mentioned micro light-emitting device 1. Specifically, the material of the above-mentioned color conversion layer 114 can be red quantum dots to enable the color conversion layer 114 to convert the blue light emitted by the first light-emitting layer 102 into red light.

[0095] Specifically, as Figure 4As shown, the above-mentioned second light-emitting unit 10B may further include a light-blocking layer 115. Moreover, in the second light-emitting unit 10B, the light-blocking layer 115 covers the micro light-emitting structure 100 of the second light-emitting unit 10B, and an opening 1151 is provided on the light-blocking layer 115. The opening 1151 is located on the side of the micro light-emitting structure 100 of the second light-emitting unit 10B facing away from the driving substrate 200, penetrates the light-blocking layer 115, and the above-mentioned color conversion layer 101 fills the opening 1151. In this way, it can be realized that the light emitted by the first light-emitting layer 102 in the micro light-emitting structure 100 of the second light-emitting unit 10B and propagating into the opening 1151 can be converted into light of a target color by the above-mentioned color conversion layer 114, and the light emitted by the first light-emitting layer 102 and propagating to other regions of the light-blocking layer 115 except the region where the opening 1151 is located cannot pass through the light-blocking layer 115, so as to ensure that the second light-emitting unit 10B only provides light of the target color.

[0096] Exemplarily, as Figure 4 shown, the above-mentioned color conversion layer 114 may be entirely filled in the opening 1151, and the above-mentioned light-blocking layer 115 may be a black matrix.

[0097] Specifically, as Figure 4 shown, in the above-mentioned second light-emitting unit 10B, the outermost layer of the micro light-emitting structure 100 of the second light-emitting unit 10B facing away from the driving substrate 200 may be an electrical connection structure 110, and the electrical connection structure 110 may be light-transmissive. For example, specifically, it may be transparent, so as to avoid the electrical connection structure 110 blocking the light emitted by the first light-emitting layer 102 and improve the light extraction efficiency of the above-mentioned micro light-emitting device 1.

[0098] In the above-mentioned embodiment, as Figure 4 shown, the above-mentioned driving substrate 200 may include a second substrate 201, a driving circuit 202, a first driving-side conductive structure 203A, a second driving-side conductive structure 203B, and a third driving-side conductive structure 203C. Among them, the driving circuit 202 is provided on one side of the second substrate 201, and the first driving-side conductive structure 203A, the second driving-side conductive structure 203B, and the third driving-side conductive structure 203C are provided on the same side of the driving circuit 202 facing away from the second substrate 201 and are all electrically connected to the driving circuit 202.

[0099] Specifically, in the above-mentioned embodiment where the micro light-emitting device 1 includes the first light-emitting unit 10A, as Figure 4As shown, the first electrode 106 of the micro-light-emitting structure 100 in the first light-emitting unit 10A can be correspondingly bonded to the first driving-side conductive structure 203A of the driving substrate 200, and the second electrode 107 of the micro-light-emitting structure 100 in the first light-emitting unit 10A can be correspondingly bonded to the second driving-side conductive structure 203B of the driving substrate 200. Moreover, in the above embodiment where the micro-light-emitting structure 100 in the first light-emitting unit 10A includes a third electrode 108, as Figure 4 shown, the third electrode 108 of the micro-light-emitting structure 100 in the first light-emitting unit 10A can be correspondingly bonded to the third driving-side conductive structure 203C of the driving substrate 200 to achieve electrical connection between the third semiconductor layer 105 of the micro-light-emitting structure 100 in the first light-emitting unit 10A and the driving substrate 200.

[0100] Specifically, in the above embodiment where the micro-light-emitting device 1 includes a second light-emitting unit 10B, as Figure 4 shown, the first electrode 106 of the micro-light-emitting structure 100 in the second light-emitting unit 10B can be correspondingly bonded to the first driving-side conductive structure 203A of the driving substrate 200, and the second electrode 107 of the micro-light-emitting structure 100 in the second light-emitting unit 10B can be correspondingly bonded to the second driving-side conductive structure 203B of the driving substrate 200.

[0101] Moreover, during specific implementation, as Figure 4 shown, the above driving substrate 200 may further include a second dielectric layer 204. The second dielectric layer 204, the first driving-side conductive structure 203A, the second driving-side conductive structure 203B, and the third driving-side conductive structure 203C are disposed on the same side of the driving circuit 202 facing away from the second substrate 201, and the second dielectric layer 204 covers the second substrate 201 and the driving circuit 202. The first driving-side conductive structure 203A, the second driving-side conductive structure 203B, and the third driving-side conductive structure 203C all penetrate through the second dielectric layer 203 and are electrically connected to the driving circuit 202.

[0102] In some examples, the material of the above first driving-side conductive structure 203A may include metals such as Cu (copper), Ag (silver), Au (gold), and Ni (nickel). The material of the above second driving-side conductive structure 203B may include metals such as Cu (copper), Ag (silver), Au (gold), and Ni (nickel). The material of the above third driving-side conductive structure 203C may include metals such as Cu (copper), Ag (silver), Au (gold), and Ni (nickel). Moreover, during specific implementation, the above first driving-side conductive structure 203A, second driving-side conductive structure 203B, and third driving-side conductive structure 203C may have the same material. For example, they may all be copper and may be formed synchronously.

[0103] In some examples, the material of the second dielectric layer 204 described above may include insulating materials such as silicon oxide, silicon nitride, and / or aluminum oxide.

[0104] Specifically, in the driving circuit 200, the surface of the second dielectric layer 204 facing away from the second substrate 201 and the driving circuit 202 may be a flat surface. Moreover, in the above-mentioned micro-light-emitting device 1, the second dielectric layer 204 of the driving substrate 200 may be correspondingly bonded to the first dielectric layer 111 of the micro-light-emitting unit 100, thereby improving the bonding strength between the driving substrate 200 and the micro-light-emitting unit 100 in the above-mentioned micro-light-emitting device 1.

[0105] In some specific embodiments, as Figure 4 shown, the micro-light-emitting structure 100 in the second light-emitting unit 10B described above may include a third electrode 108. Moreover, the third electrode 108 of the micro-light-emitting structure 100 in the second light-emitting unit 10B may be correspondingly bonded to the third driving conductive structure 203C of the driving substrate 200 to achieve electrical connection between the third semiconductor layer 105 of the micro-light-emitting structure 100 in the second light-emitting unit 10B and the driving substrate 200; or, as Figure 4 shown, the third electrode 108 of the micro-light-emitting structure 100 in the second light-emitting unit 10B may not be bonded to the third driving conductive structure 203C of the driving substrate 200 to achieve non-electrical connection between the third semiconductor layer 105 of the micro-light-emitting structure 100 in the second light-emitting unit 10B and the driving substrate 200. Thus, for the second light-emitting unit 10B, corresponding driving signals (such as driving voltages) can be provided to the first electrode 106 and the second electrode 107 of the micro-light-emitting structure 100 respectively through the driving substrate 200, and no corresponding driving signal is provided to the third electrode 108, so as to achieve only driving the first light-emitting layer 102 of the micro-light-emitting structure 100 to emit light, without driving the second light-emitting layer 104 to emit light. Therefore, it is possible to achieve that the micro-light-emitting structure 100 in the second light-emitting unit 10B emits only one color of light, and this one color of light can be converted into the target color of light by the above-mentioned color conversion layer 114 to ensure full-color display can be achieved.

[0106] In some other specific embodiments, as Figure 5As shown, the micro-light-emitting structure 100 in the second light-emitting unit 10B may not include the third electrode 108, and the third semiconductor layer 105 of the micro-light-emitting structure 100 in the second light-emitting unit 10B is not electrically connected to the driving substrate 200, so that the driving substrate 200 can only drive the first light-emitting layer 102 of the micro-light-emitting structure 100 to emit light, and cannot drive the second light-emitting layer 104 to emit light. Therefore, the micro-light-emitting structure 100 in the second light-emitting unit 10B emits only one color of light, and this one color of light can be converted into the light of the target color by the color conversion layer 114 to ensure full-color display can be achieved.

[0107] In some embodiments, as Figure 4 and Figure 5 shown, the micro-light-emitting device 1 may further include a cover plate 116. The cover plate 116 is disposed on the side of the micro-light-emitting unit 10 facing away from the driving substrate 200 and is used to protect the structures (such as the color conversion layer 114 and / or the electrical connection layer 110) disposed on the side of the micro-light-emitting unit 10 facing away from the driving substrate 200. In this way, the cover plate bonding process can be completed at the wafer level, thereby improving the manufacturing efficiency and yield of the micro-light-emitting diode full-color display device.

[0108] Specifically, as Figure 4 and Figure 5 shown, the micro-light-emitting device 1 may further include an underfill 117. The underfill 117 fills the gap between the cover plate 116 and the micro-light-emitting unit 10 to strengthen the connection firmness between the cover plate 116 and the micro-light-emitting unit 10.

[0109] Exemplarily, the cover plate 116 may specifically be a glass cover plate.

[0110] In some embodiments, as Figure 6 shown, the micro-light-emitting unit 10 may further include a microlens 118. In the micro-light-emitting unit 10, the microlens 118 included in the micro-light-emitting unit 10 is disposed on the light-emitting side of the micro-light-emitting structure 100 included in the micro-light-emitting unit 10 and can be used to improve the light-emitting efficiency of the micro-light-emitting structure 100 included in the micro-light-emitting unit 10. In this way, the lens manufacturing process can be completed at the wafer level, thereby improving the manufacturing efficiency and yield of the micro-light-emitting diode full-color display device.

[0111] And, in specific implementation, as Figure 6As shown, the above-mentioned micro-light-emitting unit 10 may further include a microlens base 119. In the micro-light-emitting unit 10, the microlens base 119 is disposed on the light-emitting side of the micro-light-emitting structure 100. The microlens base 119 and the microlens 118 may be an integrally formed structure, and specifically, the microlens 118 may be formed by the surface of the microlens base 119 facing away from the micro-light-emitting structure 100 bulging in the direction away from the micro-light-emitting structure 100 at the position corresponding to the step structure 100A.

[0112] Specifically, in the above-mentioned embodiment where the above-mentioned micro-light-emitting device 1 includes the first light-emitting unit 10A, as Figure 6 shown, the microlens base 119 and the microlens 118 of the first light-emitting unit 10A may be disposed on the side of the micro-light-emitting structure 100 of the first light-emitting unit 10A facing away from the driving substrate 200.

[0113] Specifically, in the above-mentioned embodiment where the above-mentioned micro-light-emitting device 1 includes the second light-emitting unit 10B, and the second light-emitting unit 10B includes a color conversion layer 114 and a light-blocking layer 115, as Figure 6 shown, the microlens base 119 of the second light-emitting unit 10B may be disposed between the micro-light-emitting structure 100 and the light-blocking layer 115 in the second light-emitting unit 10B. The microlens 118 of the second light-emitting unit 10B may be disposed between the micro-light-emitting structure 100 and the color conversion layer 114 in the second light-emitting unit 10B, and may be at least partially located within the opening 1151 of the light-blocking layer 115.

[0114] Exemplarily, the above-mentioned microlens 118 may be a convex lens.

[0115] Exemplarily, the material of the above-mentioned microlens 118 may include silicon oxide, and the material of the above-mentioned microlens base 119 may include silicon oxide. And, in specific implementation, the above-mentioned microlens 118 and the microlens base 119 may have the same material, for example, both may be silicon oxide.

[0116] In some examples, the above-mentioned driving substrate 200 may be a driving chip or a driving wafer.

[0117] In some examples, the above-mentioned micro-light-emitting device 1 can not only be applied to the projection part of electronic devices such as optical projection and in-vehicle head-up display (HUD), but also can be applied to the display part of electronic devices. For example, the electronic device may include: any device with a display screen such as a smart phone, a smart watch, a laptop computer, a tablet computer, a driving recorder, a navigator, a head-mounted device, etc. It can also be applied to the lighting part of electronic devices. For example, the electronic device may include: any device with a lighting component such as a vehicle, a street lamp, etc.

[0118] As described above, the micro-light-emitting device provided by the embodiment of the present application includes at least one micro-light-emitting unit, and the micro-light-emitting unit includes a micro-light-emitting structure, and the micro-light-emitting structure includes a stepped structure, a first electrode, and a second electrode. Among them, the stepped structure includes a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked. The second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, the first light-emitting layer and the second light-emitting layer have different light-emitting colors, and the stepped structure has a first stepped surface, and the first stepped surface is provided by the surface of the second semiconductor layer in the stepped structure facing away from the first light-emitting layer. The first electrode is disposed on the first stepped surface, and the second electrode is disposed on the periphery of the stepped structure and is electrically connected to the first semiconductor layer in the stepped structure. In this way, by adjusting the epitaxial growth process, structural design, and micro-nano processing, a micro-light-emitting structure that can simultaneously emit two colors of light (for example, blue light and green light) can be obtained, and one of the electrodes in the micro-light-emitting structure that can simultaneously emit two colors of light provided by the embodiment of the present application is disposed on the periphery of the stepped structure, rather than on the stepped surface of the stepped structure, so that the number of stepped surfaces that need to be formed when etching the micro-light-emitting diode epitaxial wafer can be reduced, which is beneficial to reducing the process difficulty of forming the stepped structure by etching the micro-light-emitting diode epitaxial wafer, and reducing the yield risk that may be brought by the process of forming the stepped structure by etching the micro-light-emitting diode epitaxial wafer. Therefore, the manufacturing efficiency and yield of the dual-color micro-light-emitting diode chip can be improved, and by using the micro-light-emitting structure that can simultaneously emit two colors of light to achieve full-color display, the manufacturing efficiency and yield of the micro-light-emitting diode full-color display device can be improved.

[0119] Please refer to Figure 7 , Figure 7 which is a schematic flowchart of the manufacturing method of the micro-light-emitting device provided by the embodiment of the present application. Please also refer to Figures 1 to 6 and Figures 8 to 16 , Figures 1 to 6 and Figures 8 to 16 which are schematic structural diagrams in the manufacturing process of the micro-light-emitting device provided by the embodiment of the present application. The specific process of the manufacturing method of the micro-light-emitting device provided by this embodiment can be as follows:

[0120] Step S11: Provide an epitaxial stack 1000. The epitaxial stack 1000 has a pixel region C1 and a non-pixel region C2 disposed around the pixel region C1, and includes a light-emitting stack 12. The light-emitting stack 12 includes a first semiconductor layer 101, a first light-emitting layer 102, a second semiconductor layer 103, a second light-emitting layer 104, and a third semiconductor layer 105 that are sequentially stacked. Among them, the second semiconductor layer 103 and the first semiconductor layer 101 have different polarities, the third semiconductor layer 105 and the first semiconductor layer 101 have the same polarity, and the first light-emitting layer 102 and the second light-emitting layer 104 have different light-emitting colors (such asFigure 8 as shown

[0121] In this embodiment, as Figure 8 shown, the epitaxial stack 1000 can be a micro light-emitting diode epitaxial wafer with two emission colors, and the micro light-emitting diode epitaxial wafer can be obtained by commercial purchase.

[0122] Specifically, as Figure 8 shown, the epitaxial stack 1 can have a plurality of pixel regions C1, and the non-pixel region C2 can be an interval region between the plurality of pixel regions C1 and is used to separate each pixel region C1 from other pixel regions C1 located around it.

[0123] Specifically, as Figure 8 shown, the epitaxial stack 1000 can further include a substrate 11, a light-emitting stack 12 is disposed on one side of the substrate 11, and a first semiconductor layer 101, a first light-emitting layer 102, a second semiconductor layer 103, a second light-emitting layer 104, and a third semiconductor layer 105 are sequentially stacked on the substrate 11. And, in the epitaxial stack 1000, the substrate 11 can include a first substrate 111, and the first substrate 111 is used to support the film layer structure thereon and can be a sapphire substrate, a silicon substrate, a silicon carbide substrate, etc.

[0124] In some embodiments, as Figure 8 shown, in the epitaxial stack 1000, the substrate 11 can further include a buffer layer 112, the buffer layer 112 is disposed on one side of the first substrate 111, and the above-mentioned light-emitting stack 12 is disposed on the side of the buffer layer 112 away from the first substrate 111. The buffer layer 112 can relieve the stress generated between the light-emitting stack 12 and the first substrate 111 due to lattice mismatch and coefficient of thermal expansion mismatch, and the material of the buffer layer 112 can include buffer materials such as silicon nitride, silicon oxide, gallium nitride, or aluminum nitride. In one example, the buffer layer 112 can be an unintentionally doped gallium nitride (U-GaN) layer.

[0125] And, in specific implementation, as Figure 8 shown, the buffer layer 112, the first semiconductor layer 101, the first light-emitting layer 102, the second semiconductor layer 103, the second light-emitting layer 104, and the third semiconductor layer 105 can be sequentially formed on one side of the first substrate 111 by a thin film deposition process to obtain the above-mentioned epitaxial stack 1000.

[0126] Step S12: Etch the light-emitting stack 12 so that a stepped structure 100A is formed in the portion of the light-emitting stack 12 corresponding to the pixel region C1, and the portion of the light-emitting stack 12 corresponding to the non-pixel region C2 is removed. The stepped structure 100A has a first stepped surface F1, and the first stepped surface F1 is provided by the surface of the second semiconductor layer 103 in the stepped structure 100A facing away from the first light-emitting layer 102 (as Figure 9 shown).

[0127] Specifically, in the above embodiment where the epitaxial stack 1000 further includes a substrate 11, as Figure 9 shown, after the etching of the light-emitting stack 12 is completed, the portion of the light-emitting stack 12 corresponding to each pixel region C1 will correspondingly become a stepped structure 100A, and the portion of the light-emitting stack 12 corresponding to the non-pixel region C2 will be removed, so that the region of the first surface of the substrate 11 facing the light-emitting stack 12 (i.e., the upper surface) corresponding to the non-pixel region C2 is exposed.

[0128] Moreover, in specific implementation, after obtaining the above epitaxial stack 1000, the light-emitting stack 12 in the pixel region C1 can be etched through an etching process so that the light-emitting stack 12 in the pixel region C1 becomes a stepped structure 100A, and the light-emitting stack 12 in the non-pixel region C1 is etched to remove the light-emitting stack 12 in the non-pixel region C1, so that the region of the first surface of the substrate 11 facing the light-emitting stack 12 corresponding to the non-pixel region C2 is exposed.

[0129] In some embodiments, before the above step S11 and before the above step S12, the manufacturing method of the above micro light-emitting device may further include: forming a current diffusion layer 109 on the side of the light-emitting stack 12 facing away from the substrate 11 (as Figure 10 shown). Specifically, as Figure 10 shown, the current diffusion layer 109 can be obtained by evaporating a semiconductor oxide on the surface of the light-emitting stack 12 facing away from the substrate 11 to form current conduction, where the semiconductor oxide includes but is not limited to indium tin oxide (ITO), zinc oxide (ZnO), etc., so as to form an ohmic contact.

[0130] Correspondingly, the above step S12 may specifically include: etching the light-emitting stack 12 and the current diffusion layer 13 so that a stepped structure 100A is formed in the portion of the light-emitting stack 12 corresponding to the pixel region C1, retaining the current diffusion layer 109 on the surface of the third semiconductor layer 105 in the stepped structure 100A facing away from the second light-emitting layer 104, and removing the portion of the light-emitting stack 12 corresponding to the non-pixel region C2 so that the region of the first surface of the substrate 11 facing the light-emitting stack 12 corresponding to the non-pixel region C2 is exposed (as Figure 11 shown).

[0131] Specifically, as Figure 11 shown, a mask layer can be deposited on the surface of the current diffusion layer 109 facing away from the light-emitting stack 121. The mask layer includes, but is not limited to, etch-resistant materials such as photoresist, insulating layers, or compositions of these materials. Then, using the mask layer, the light-emitting stack 12 and the current diffusion layer 13 are etched through yellow light and etching processes, so that a stepped structure 100A is formed in the portion of the light-emitting stack 12 corresponding to the pixel region C1. The current diffusion layer 109 on the surface of the third semiconductor layer 105 facing away from the second light-emitting layer 104 in the stepped structure 100A is retained, and the portion of the light-emitting stack 12 corresponding to the non-pixel region C2 is removed, so that the first surface of the substrate 11 (for example, the first substrate 111 or the buffer layer 112) facing the light-emitting stack 12 corresponding to the non-pixel region C2 is exposed. Then, the remaining mask layer can be removed by a wet process.

[0132] Step S13: Form a first electrode 106 on the first step surface F1 of the stepped structure 100A, and form a second electrode 107 around the stepped structure 100A in the non-pixel region C2 (as Figure 12 shown).

[0133] Specifically, as Figure 12 shown, in the structure obtained after the above step S13 is completed, the number of stepped structures 100A, the number of first electrodes 106, and the number of second electrodes 107 can be equal. For example, they can all be at least one. Moreover, the stepped structures 100A and the first electrodes 106 can be in one-to-one correspondence, the stepped structures 100A and the second electrodes 107 can be in one-to-one correspondence, and each first electrode 106 can be disposed on the first step surface F1 of its corresponding stepped structure 100A, and each second electrode 107 can be disposed around its corresponding stepped structure 100A.

[0134] In some embodiments, after the above step S12 and before the following step S14, the manufacturing method of the above micro light-emitting device may further include:

[0135] Step A: Form a third electrode 108 on the side of the third semiconductor layer 105 in the stepped structure 100A facing away from the second light-emitting layer 104 (as Figure 12 shown).

[0136] Specifically, in the above embodiment where the current diffusion layer 109 is provided on the surface of the third semiconductor layer 105 in the stepped structure 100A facing away from the second light-emitting layer 104, the above step A may specifically include: forming a third electrode 108 on the side of the current diffusion layer 109 facing away from the third semiconductor layer 105 in the stepped structure 100A (as Figure 12 shown).

[0137] Specifically, in the above-described embodiment where the epitaxial stack 1000 further includes the substrate 11, as Figure 12 shown, the above step S13 may specifically include:

[0138] Step S131: Form a first electrode layer 1601 on the first step surface F1 of the step structure 100A, and form a second electrode layer 1071 on the periphery of the step structure 100A in the region of the first surface of the substrate 11 corresponding to the non-pixel region C2.

[0139] Specifically, through a deposition process, a metal material (such as Ti, Au, Pt, Ni, and / or Al, etc.) may be deposited on the first step surface F1 of each step structure 100A to form the first electrode layer 1061, and a metal material (such as Ti, Au, Pt, Ni, and / or Al, etc.) may be deposited on the periphery of the step structure 100A in the region of the first surface of the substrate 11 corresponding to the non-pixel region C2 to form the second electrode layer 1071.

[0140] Step S132: Form a first dielectric layer 111, and the first dielectric layer 111 covers the substrate 11, the step structure 100A, the first electrode layer 1061, and the second electrode layer 1071.

[0141] Specifically, through a deposition process, a first dielectric layer 111 covering the substrate 11, the step structure 100A, the first electrode layer 1061, and the second electrode layer 1071 may be formed.

[0142] Step S133: Form a first conductive structure 1062 and a second conductive structure 1072 to obtain a first electrode 106 including the first electrode layer 1061 and the first conductive structure 1062 and a second electrode 1077 including the second electrode layer 1071 and the second conductive structure 1072, wherein the first conductive structure 1062 penetrates through the first dielectric layer 111 and is electrically connected to the first electrode layer 1061, and the second conductive structure 1072 penetrates through the first dielectric layer 111 and is electrically connected to the second electrode layer 1071.

[0143] Specifically, the surface of the first dielectric layer 111 facing away from the substrate 11, the step structure 100A, the first electrode layer 1061, and the second electrode layer 1071 may be a flat surface.

[0144] Moreover, in specific implementation, the first dielectric layer 111 can be etched through an etching process to form a first through hole penetrating the first dielectric layer 111 in a region corresponding to the first electrode layer 1061 on the surface of the first dielectric layer 111 facing away from the substrate 11, the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071, and a second through hole penetrating the first dielectric layer 111 in a region corresponding to the second electrode layer 1071 on the surface of the first dielectric layer 111 facing away from the substrate 11, the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071. Then, copper is electroplated on the surface of the first dielectric layer 111 facing away from the substrate 11, the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071 through an electroplating process, and the height of the copper is greater than the height of the first dielectric layer 111. Then, the copper on the surface of the first dielectric layer 111 facing away from the substrate 11, the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071 is polished flat through a chemical mechanical polishing (CMP) process, and only the copper in the first through hole and the second through hole is retained, obtaining a first conductive structure 1062 and a second conductive structure 1072 respectively filled in the first through hole and the second through hole, and making the surface of the first dielectric layer 111 facing away from the substrate 11, the stepped structure 100A, the first electrode layer 1061, and the second electrode layer 1071 a flat surface.

[0145] In some embodiments, the manufacturing method of the above-mentioned micro light-emitting device may further include: providing a driving substrate 200 (as Figure 13 shown). Specifically, as Figure 13 shown, the driving substrate 200 may include a second substrate 201, a driving circuit 202, a second dielectric layer 204, a first driving-side conductive structure 203A, and a second driving-side conductive structure 203B. Among them, the driving circuit 202 is disposed on one side of the second substrate 201, the second dielectric layer 204 covers the second substrate 201 and the driving circuit 202, and the surface of the second dielectric layer 204 facing away from the second substrate 201 and the driving circuit 202 may be a flat surface. The first driving-side conductive structure 203A and the second driving-side conductive structure 203B are disposed on the side of the driving circuit 202 facing away from the second substrate 201, and both penetrate the second dielectric layer 204 and are electrically connected to the driving circuit 202.

[0146] Moreover, after the above step S13 and before the following step S14, the manufacturing method of the above-mentioned micro light-emitting device may further include: respectively bonding the first conductive structure 1062 and the second conductive structure 1072 to the first driving-side conductive structure 203A and the second driving-side conductive structure 203B correspondingly, and bonding the first dielectric layer 111 to the second dielectric layer 204 correspondingly, obtaining a bonded structure (as Figure 14 shown).

[0147] Specifically, asFigure 14 As shown, the structure obtained after the completion of the above step S13 and the driving substrate 200 can be pre-treated by means of formic acid and deionized water, etc., in order to remove the oxide layer on the surface of the conductive structure 1062 / 1072 / 1082 / 203A / 203B / 203C and improve the surface hydrophilicity and bonding strength. Then, the structure obtained after the completion of step S13 and the driving substrate 200 are aligned and bonded, and then a certain pressure is applied under a certain high temperature condition and maintained for a certain time, and annealed in a nitrogen annealing furnace for a certain time, so as to obtain a bonding structure (such as Figure 14 shown).

[0148] Specifically, in the above embodiment where the epitaxial stack 1000 further includes a substrate 11, before the following step S14, the method for manufacturing the micro light-emitting device may further include:

[0149] Step B: Remove the substrate 11 so that the second electrode 103 faces the first surface of the substrate 11 and the first semiconductor layer 101 in the step structure 100A faces the first surface of the substrate 11 is exposed (eg, Figure 15 shown).

[0150] Specifically, when obtaining Figure 14 After forming the bonding structure as shown, the substrate 11 of the bonding structure may be removed to expose the second electrode 107 facing the first surface of the substrate 11 and the first semiconductor layer 101 in the stepped structure 100A facing the first surface of the substrate 11 .

[0151] Specifically, the base 11 may include a first substrate 111 and a buffer layer 112, and the step of removing the base 11 may include: first removing the first substrate 111 by a laser lift-off process or an etching process, and then removing the buffer layer 112 by a dry etching process, so as to ensure that the first semiconductor layer 101 and the second electrode 107 are completely exposed. In addition, in a specific implementation, after removing the buffer layer 112, a KOH solution of a certain concentration may be used to repair and process the exposed surface of the first semiconductor layer 101, so as to ensure the electrical performance of the first semiconductor layer 101.

[0152] Step S14: forming an electrical connection structure 110 on the side of the step structure 100A away from the first electrode 106, the electrical connection structure 110 electrically connects the second electrode 107 and the first semiconductor layer 101 in the step structure 100A accordingly (eg Figure 16 shown).

[0153] Specifically, in the above embodiment where the epitaxial stack 1000 further includes a substrate 11,Figures 14 to 16 As shown, after removing the substrate 11 to expose the first surface of the second electrode 103 facing the substrate 11 and the first surface of the first semiconductor layer 101 in the step structure 100A facing the substrate 11, an electrical connection structure 110 can be deposited on the first surface of the second electrode 107 and the first surface of the first semiconductor layer 101 in the step structure 100A by yellow light lithography, enabling it to form an ohmic contact with the second electrode 107 and the first semiconductor layer 101 in the step structure 100A, thereby realizing the electrical connection between the second electrode 107 and the first semiconductor layer 101 in the step structure 100A.

[0154] In the above embodiment, the number of the pixel regions C1 in the epitaxial stack 1000 can be at least one, the non-pixel region C2 can be disposed around each pixel region C1, and the number of the micro-light emitting structures 100 obtained after forming the electrical connection structure 110 on the side of the step structure 100A facing away from the first electrode 106 can be at least one, and the at least one micro-light emitting structure 100 and the at least one pixel region C1 can correspond one by one, and at least one of the at least one pixel regions C1 can be a first pixel region. And, before the above step S14, the manufacturing method of the above micro-light emitting device can further include:

[0155] Step S15: Form a color conversion layer 114, the color conversion layer 114 covers the micro-light emitting structure 100 corresponding to the first pixel region, and is configured to convert the light emitted by the first light emitting layer 102 in the micro-light emitting structure 100 corresponding to the first pixel region into light of a target color, and the light of the target color, the light reflected by the first light emitting layer 102, and the light emitted by the second light emitting layer 104 are used to synthesize white light (as Figure 4 shown).

[0156] Specifically, as Figure 4 shown, the step of forming the color conversion layer 114 can include: forming a light blocking layer 115, the light blocking layer 115 covers the micro-light emitting structure 100 corresponding to the first pixel region, and an opening 1151 is provided on the light blocking layer 115, the opening 1151 is located on the light emitting side of the micro-light emitting structure 100 corresponding to the first pixel region and penetrates the light blocking layer 115; forming the color conversion layer 114 in the opening 1151.

[0157] In some embodiments, after the above step S14, the manufacturing method of the above micro-light emitting device can further include:

[0158] Step S16: Form a microlens 118 on the light emitting side of the micro-light emitting structure 100 (as Figure 6 shown).

[0159] Specifically, after obtaining the structure obtained after the above step S14 is completed, a layer of silicon oxide can be deposited on the light-emitting side of the micro-light-emitting structure 100 (i.e., the side of the electrical connection structure 110 in the micro-light-emitting structure 100 away from the step structure 100A), and the main functions of this layer of silicon oxide are two: first, it is used as a passivation layer to protect the influence of the external air on the electrical connection structure 110; second, it is used as a material for making microlenses 118, and the silicon oxide layer is etched by yellow light and etching process, so that a microlens 118 can be formed on the light-emitting side of each micro-light-emitting structure 100. In this way, the microlens manufacturing process can be completed at the wafer level, simplifying the full-color process flow.

[0160] Furthermore, in a specific implementation, the step of forming the color conversion layer 114 may include: forming a light blocking layer 115, the light blocking layer 115 covers the micro-light emitting structure 100 and the micro-lens 118 corresponding to the first pixel area, and an opening 1151 is provided on the light blocking layer 115, the opening 1151 is located on the light emitting side of the micro-light emitting structure 100 corresponding to the first pixel area, and passes through the light blocking layer 115, the micro-lens 118 is at least partially located in the opening 1151 of the light blocking layer 115; forming the color conversion layer 114 in the opening 1151, the color conversion layer 114 covers the micro-lens 118.

[0161] In some specific embodiments, Figure 6 As shown, after forming the color conversion layer 114 and / or the microlens 118, the method for manufacturing the micro light-emitting device may further include: arranging a cover plate 116 on the side of the color conversion layer 114 and / or the microlens 118 away from the micro light-emitting structure 100; forming an underfill 117, the underfill 117 filling the gap between the cover plate 116 and the color conversion layer 114 and / or the microlens 118. In this way, the cover plate bonding process can be completed at the wafer level, simplifying the full-color process flow.

[0162] It should be noted that the specific structure of the micro-light emitting device in this embodiment can refer to the specific implementation in the above-mentioned embodiment of the micro-light emitting device, so it will not be repeated here.

[0163] As described above, in the method for manufacturing a micro light-emitting device provided by the embodiments of the present application, by providing an epitaxial stack, the epitaxial stack has a pixel region and a non-pixel region disposed around the pixel region, and includes a light-emitting stack. The light-emitting stack includes a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked. Among them, the second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, and the first light-emitting layer and the second light-emitting layer have different light-emitting colors. Then, the light-emitting stack is etched so that a stepped structure is formed in the part of the light-emitting stack corresponding to the pixel region, and the part of the light-emitting stack corresponding to the non-pixel region is removed. Among them, the stepped structure has a first stepped surface, and the first stepped surface is provided by the surface of the second semiconductor layer in the stepped structure facing away from the first light-emitting layer. After that, a first electrode is formed on the first stepped surface of the stepped structure, and a second electrode is formed in the non-pixel region around the stepped structure. Then, an electrical connection structure is formed on the side of the stepped structure facing away from the first electrode. The electrical connection structure electrically connects the second electrode and the first semiconductor layer in the stepped structure, and a micro light-emitting structure including the stepped structure, the first electrode, the second electrode, and the electrical connection structure is obtained. Thus, a micro light-emitting structure capable of simultaneously emitting two colors of light (for example, blue light and green light) is provided. Moreover, in the micro light-emitting structure capable of simultaneously emitting two colors of light provided by the embodiments of the present application, one electrode is disposed around the stepped structure instead of on the stepped surface of the stepped structure. Therefore, the number of stepped surfaces that need to be formed when etching the micro light-emitting diode epitaxial wafer can be reduced, which is beneficial to reducing the process difficulty of forming the stepped structure by etching the micro light-emitting diode epitaxial wafer and reducing the yield risk that may be brought by the process of forming the stepped structure by etching the micro light-emitting diode epitaxial wafer. Therefore, the manufacturing efficiency and yield of the dual-color micro light-emitting diode chip can be improved. And by using the micro light-emitting structure capable of simultaneously emitting two colors of light to achieve full-color display, the manufacturing efficiency and yield of the micro light-emitting diode full-color display device can be improved.

[0164] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The features, structures, or characteristics described above can be combined in one or more embodiments in any suitable manner.

[0165] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A micro light-emitting device, characterized in that, Comprising at least one micro-light-emitting unit, the micro-light-emitting unit comprising a micro-light-emitting structure, the micro-light-emitting structure comprising: A stepped structure, the stepped structure comprising a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked, wherein the second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, the first light-emitting layer and the second light-emitting layer have different emission colors, and the stepped structure has a first stepped surface, the first stepped surface being provided by the surface of the second semiconductor layer in the stepped structure facing away from the first light-emitting layer; A first electrode and a second electrode, the first electrode being disposed on the first stepped surface, and the second electrode being disposed on the periphery of the stepped structure and electrically connected to the first semiconductor layer in the stepped structure.

2. The micro light-emitting device according to claim 1, wherein The micro-light-emitting structure further comprises: An electrical connection structure, the stepped structure and the second electrode being disposed on the same side of the electrical connection structure, and the surface of the first semiconductor layer in the stepped structure facing away from the first light-emitting layer being oriented towards the electrical connection structure, and the second electrode being electrically connected to the first semiconductor layer in the stepped structure through the electrical connection structure.

3. The micro light-emitting device according to claim 2, characterized in that, The electrical connection structure comprises an ohmic contact layer, and the ohmic contact layer forms ohmic contacts with the second electrode and the first semiconductor layer in the stepped structure respectively.

4. The micro light-emitting device according to claim 1, characterized in that, The micro-light-emitting device further comprises a driving substrate; and, in the micro-light-emitting device, at least one of the micro-light-emitting units is a first light-emitting unit, and in the first light-emitting unit, the micro-light-emitting structure of the first light-emitting unit is bonded to the driving substrate through the first electrode and the second electrode, and the third semiconductor layer of the micro-light-emitting structure of the first light-emitting unit is electrically connected to the driving substrate.

5. The micro light-emitting device according to claim 4, wherein, In the first light-emitting unit, the micro-light-emitting structure of the first light-emitting unit further comprises a third electrode, the third electrode being disposed on the side of the third semiconductor layer in the stepped structure facing away from the second light-emitting layer, and the micro-light-emitting structure of the first light-emitting unit is bonded to the driving substrate through the first electrode, the second electrode, and the third electrode.

6. The micro-light-emitting device according to claim 1, characterized in that, The micro-light-emitting device further comprises a driving substrate; and, in the micro-light-emitting device, at least one of the micro-light-emitting units is a second light-emitting unit, the second light-emitting unit further comprising a color conversion layer, and in the second light-emitting unit, the micro-light-emitting structure of the second light-emitting unit is bonded to the driving substrate through the first electrode and the second electrode, the color conversion layer covering the micro-light-emitting structure of the second light-emitting unit and being configured to convert the light emitted by the first light-emitting layer into light of a target color, and the light of the target color, the light reflected by the first light-emitting layer, and the light emitted by the second light-emitting layer are used to synthesize white light.

7. The micro light-emitting device according to claim 6, characterized in that, The second light-emitting unit further includes a light-blocking layer. In the second light-emitting unit, the light-blocking layer covers the micro light-emitting structure of the second light-emitting unit, and an opening is provided on the light-blocking layer. The opening is located on a side of the micro light-emitting structure of the second light-emitting unit facing away from the driving substrate and penetrates through the light-blocking layer, and the color conversion layer fills the opening.

8. The micro-light-emitting device according to claim 1, wherein The micro light-emitting unit further includes a microlens. In the micro light-emitting unit, the microlens of the micro light-emitting unit is provided on a light-emitting side of the micro light-emitting structure of the micro light-emitting unit.

9. The micro-light-emitting device according to claim 1, wherein, The first electrode includes a first electrode layer and a first conductive structure that are sequentially stacked along the stacking direction of the step structure; the second electrode includes a second electrode layer and a second conductive structure that are sequentially stacked along the stacking direction of the step structure; and, the micro light-emitting structure further includes: A first dielectric layer that covers the step structure, the first electrode layer, and the second electrode layer. The first conductive structure penetrates through the first dielectric layer and is electrically connected to the first electrode layer. The second conductive structure penetrates through the first dielectric layer and is electrically connected to the second electrode layer, and a surface of the first dielectric layer facing away from the step structure, the first electrode layer, and the second electrode layer is a flat surface.

10. A manufacturing method of a micro light-emitting device, characterized in that, Comprising: Providing an epitaxial stack that has a pixel region and a non-pixel region provided around the pixel region, and includes a light-emitting stack. The light-emitting stack includes a first semiconductor layer, a first light-emitting layer, a second semiconductor layer, a second light-emitting layer, and a third semiconductor layer that are sequentially stacked. Among them, the second semiconductor layer and the first semiconductor layer have different polarities, the third semiconductor layer and the first semiconductor layer have the same polarity, and the first light-emitting layer and the second light-emitting layer have different light-emitting colors; Etching the light-emitting stack so that a part of the light-emitting stack corresponding to the pixel region forms a step structure, and removing a part of the light-emitting stack corresponding to the non-pixel region. Among them, the step structure has a first step surface, and the first step surface is provided by a surface of the second semiconductor layer in the step structure facing away from the first light-emitting layer; Forming a first electrode on the first step surface of the step structure, and forming a second electrode on the periphery of the step structure in the non-pixel region; Forming an electrical connection structure on a side of the step structure facing away from the first electrode. The electrical connection structure electrically connects the second electrode and the first semiconductor layer in the step structure to obtain a micro light-emitting structure including the step structure, the first electrode, the second electrode, and the electrical connection structure.

11. The manufacturing method of the micro light-emitting device according to claim 10, characterized in that, Before forming the electrical connection structure on a side of the step structure facing away from the first electrode, the manufacturing method of the micro light-emitting device further includes: Forming a third electrode on a side of the third semiconductor layer in the step structure facing away from the second light-emitting layer.

12. The manufacturing method of the micro light-emitting device according to claim 11, wherein Before etching the light-emitting stack to form a stepped structure in a portion of the light-emitting stack corresponding to the pixel region and removing a portion of the light-emitting stack corresponding to the non-pixel region, the method for manufacturing the micro light-emitting device further includes: forming a current diffusion layer on a side of the light-emitting stack facing away from the substrate; The etching of the light-emitting stack to form a stepped structure in a portion of the light-emitting stack corresponding to the pixel region and removing a portion of the light-emitting stack corresponding to the non-pixel region includes: etching the light-emitting stack and the current diffusion layer to form a stepped structure in a portion of the light-emitting stack corresponding to the pixel region, retaining the current diffusion layer on a surface of the third semiconductor layer facing away from the second light-emitting layer in the stepped structure, and removing a portion of the light-emitting stack corresponding to the non-pixel region; The forming of a third electrode on a side of the third semiconductor layer facing away from the second light-emitting layer in the stepped structure includes: forming a third electrode on a side of the current diffusion layer facing away from the third semiconductor layer in the stepped structure.

13. The manufacturing method of the micro light-emitting device according to claim 10, characterized in that, The epitaxial stack further includes a substrate, the light-emitting stack is disposed on one side of the substrate, and the first semiconductor layer, the first light-emitting layer, the second semiconductor layer, the second light-emitting layer, and the third semiconductor layer are sequentially stacked on the substrate; Before forming an electrical connection structure on a side of the stepped structure facing away from the first electrode, the method for manufacturing the micro light-emitting device further includes: removing the substrate to expose a first surface of the second electrode facing the substrate and a first surface of the first semiconductor layer in the stepped structure facing the substrate; The forming of an electrical connection structure on a side of the stepped structure facing away from the first electrode includes: forming an electrical connection structure on the first surface of the second electrode and the first surface of the first semiconductor layer in the stepped structure.

14. The manufacturing method of the micro light-emitting device according to claim 13, characterized in that, The forming of a first electrode on the first step surface of the stepped structure and a second electrode on the periphery of the stepped structure in the non-pixel region includes: forming a first electrode layer on the first step surface of the stepped structure and forming a second electrode layer on the periphery of the stepped structure in a region of the first surface of the substrate corresponding to the non-pixel region; forming a first dielectric layer that covers the substrate, the stepped structure, the first electrode layer, and the second electrode layer; forming a first conductive structure and a second conductive structure to obtain a first electrode including the first electrode layer and the first conductive structure and a second electrode including the second electrode layer and the second conductive structure, wherein the first conductive structure penetrates the first dielectric layer and is electrically connected to the first electrode layer, the second conductive structure penetrates the first dielectric layer and is electrically connected to the second electrode layer, and a surface of the first dielectric layer facing away from the substrate, the stepped structure, the first electrode layer, and the second electrode layer is a flat surface.

15. The manufacturing method of the micro light-emitting device according to claim 14, wherein The method for manufacturing the micro light-emitting device further includes: Provided is a driving substrate, which includes a substrate, a driving circuit, a second dielectric layer, a first driving-side conductive structure, and a second driving-side conductive structure. Wherein, the driving circuit is disposed on one side of the substrate, the second dielectric layer covers the substrate and the driving circuit, and the surface of the second dielectric layer facing away from the substrate and the driving circuit is a flat surface. The first driving-side conductive structure and the second driving-side conductive structure are disposed on the side of the driving circuit facing away from the substrate, and both penetrate through the second dielectric layer and are electrically connected to the driving circuit; Moreover, before removing the substrate to expose the first surface of the substrate facing the second electrode and the first surface of the first semiconductor layer in the step structure facing the substrate, the manufacturing method of the micro-light-emitting device further includes: Bonding the first conductive structure and the second conductive structure to the first driving-side conductive structure and the second driving-side conductive structure respectively, and bonding the first dielectric layer and the second dielectric layer correspondingly to obtain a bonded structure; The removing the substrate to expose the first surface of the substrate facing the second electrode and the first surface of the first semiconductor layer in the step structure includes: Removing the substrate of the bonded structure to expose the first surface of the substrate facing the second electrode and the first surface of the first semiconductor layer in the step structure.

16. The manufacturing method of the micro light-emitting device according to claim 10, characterized in that, The number of pixel regions in the epitaxial stack is at least one, the non-pixel regions are arranged around each pixel region, and after forming the electrical connection structure on the side of the step structure facing away from the first electrode, the number of micro-light-emitting structures obtained is at least one, and the at least one micro-light-emitting structure corresponds to the at least one pixel region one by one. At least one of the at least one pixel regions is a first pixel region; Moreover, after forming the electrical connection structure on the side of the step structure facing away from the first electrode, the manufacturing method of the micro-light-emitting device further includes: Forming a color conversion layer, the color conversion layer covering the micro-light-emitting structure corresponding to the first pixel region and being configured to convert the light emitted by the first light-emitting layer in the micro-light-emitting structure corresponding to the first pixel region into light of a target color, and the light of the target color, the light reflected by the first light-emitting layer, and the light emitted by the second light-emitting layer are used to synthesize white light.

17. The manufacturing method of the micro light-emitting device according to claim 16, characterized in that, The forming the color conversion layer includes: Forming a light-blocking layer, the light-blocking layer covering the micro-light-emitting structure corresponding to the first pixel region, and an opening is provided on the light-blocking layer. The opening is located on the light-emitting side of the micro-light-emitting structure corresponding to the first pixel region and penetrates through the light-blocking layer; Forming a color conversion layer in the opening.

18. The manufacturing method of the micro light-emitting device according to claim 10, characterized in that, Moreover, after forming the electrical connection structure on the side of the step structure facing away from the first electrode, the manufacturing method of the micro-light-emitting device further includes: Forming a microlens on the light-emitting side of the micro-light-emitting structure.

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