Micro-LED device and preparation method thereof, and head-mounted display equipment

Abstract

The invention discloses a Micro-LED device and a preparation method thereof, and a head-mounted display device. The Micro-LED device comprises a light-emitting unit formed by sequentially stacking a substrate layer, an n-type GaN layer, a multi-quantum well active region layer and a p-type GaN layer; the n-type electrode penetrates through the substrate layer and extends to the n-type GaN layer; wherein the surface, deviating from the multi-quantum well active region layer, of the p-type GaN layer and the side wall of the p-type GaN layer are covered with a p-type electrode layer. The p-type electrode layer covers the surface and the side wall of the p-type GaN layer, so that the p-type electrode layer forms a transverse electric field on the p-type GaN layer, holes in the p-type GaN layer are far away from the side wall and are intensively distributed in the middle area of the p-type GaN layer, the recombination probability of the holes and electrons is improved to a certain extent, the light emitting efficiency of the Micro-LED device is improved, and the service life of the Micro-LED device is prolonged. And the working performance and the working efficiency of the Micro-LED device are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of Micro-LED devices, and in particular to a Micro-LED device, a manufacturing method thereof, and a head-mounted display device. Background Art

[0002] Micro-LED devices have characteristics such as small size, high integration, and self-luminescence, and have great advantages in terms of resolution, brightness, response speed, etc. Based on the characteristics of Micro-LED devices, Micro-LED devices have great application potential in display technology fields such as VR / AR devices.

[0003] However, limited by the manufacturing process of Micro-LED chips, as the size of Micro-LED devices decreases, it is difficult to improve and enhance the working performance and working efficiency of Micro-LED devices. Summary of the Invention

[0004] The purpose of the present invention is to provide a Micro-LED device, a manufacturing method thereof, and a head-mounted display device, which can improve and enhance the working performance and working efficiency of Micro-LED devices to a certain extent.

[0005] To solve the above technical problems, the present invention provides a Micro-LED device, including: a light-emitting unit formed by sequentially stacking a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer; an n-type electrode penetrating the substrate layer and extending to the n-type GaN layer;

[0006] Wherein, a p-type electrode layer is covered on the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and on the side walls of the p-type GaN layer.

[0007] In an optional embodiment of the present application, the side walls of the multi-quantum well active region layer are inclined side walls.

[0008] In an optional embodiment of the present application, the n-type GaN layer, the multi-quantum well active region layer, and the p-type GaN layer together form a frustum of a cone or a frustum of a square pyramid.

[0009] In an optional embodiment of the present application, the included angle between the inclined side wall and the vertical direction is not greater than 45°.

[0010] In an optional embodiment of the present application, the side walls of the multi-quantum well active region layer and the n-type GaN layer are covered with an insulating layer.

[0011] A manufacturing method of a Micro-LED device for manufacturing the Micro-LED device as described in any one of the above, the manufacturing method includes:

[0012] Generate a light-emitting unit including a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer stacked in sequence;

[0013] Cover and form a p-type electrode layer on the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and on the sidewalls of the p-type GaN layer;

[0014] Fabricate and form an n-type electrode that penetrates the substrate layer of the light-emitting unit and extends to the n-type GaN layer.

[0015] In an optional embodiment of the present application, generating a light-emitting unit including a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer stacked in sequence includes:

[0016] Stack and form a structural layer including the n-type GaN layer, the multi-quantum well active region layer, and the p-type GaN layer in sequence on the substrate layer;

[0017] Patterning and etching the structural layer to form the light-emitting unit, wherein at least the sidewalls of the multi-quantum well active region layer in each light-emitting unit are etched into inclined sidewalls.

[0018] In an optional embodiment of the present application, covering and forming a p-type electrode layer on the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and on the sidewalls of the p-type GaN layer includes:

[0019] Form a p-type electrode layer on the surface of the p-type GaN layer facing away from the multi-quantum well active region layer, and on the sidewalls of the n-type GaN layer, the multi-quantum well active region layer, and the p-type GaN layer;

[0020] Etch and remove the p-type electrode layer on the sidewalls of the n-type GaN layer and the multi-quantum well active region layer.

[0021] In an optional embodiment of the present application, after covering and forming a p-type electrode layer on the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and on the sidewalls of the p-type GaN layer, it further includes:

[0022] Form an insulating layer on the sidewalls of the n-type GaN layer and the multi-quantum well active region layer.

[0023] In an optional embodiment of the present application, fabricating and forming an n-type electrode that penetrates the substrate layer of the light-emitting unit and extends to the n-type GaN layer includes:

[0024] Etch and thin the substrate layer to obtain a substrate layer with a thickness not greater than a set thickness;

[0025] Fabricate and form the n-type electrode that penetrates the etched substrate layer and extends to the n-type GaN layer.

[0026] A head-mounted display device includes the Micro-LED device described in any one of the above, and optical elements disposed on the output optical path of the Micro-LED device.

[0027] A Micro-LED device provided by the present invention, a preparation method thereof, and a head-mounted display device; the Micro-LED device includes: a light-emitting unit formed by sequentially stacking a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer; an n-type electrode that penetrates the substrate layer and extends to the n-type GaN layer; wherein, a p-type electrode layer is disposed to cover the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and the side walls of the p-type GaN layer.

[0028] In the Micro-LED device of the present application, on the basis of covering and forming a p-type electrode layer on the surface of the p-type GaN layer, the p-type electrode layer is further extended to cover the side walls of the p-type GaN layer, so that a transverse electric field is formed by the p-type electrode layer in the p-type GaN layer, and thus the holes in the p-type GaN layer are away from the side walls and can be more concentrated in the middle region of the p-type GaN layer. Therefore, during the operation of the Micro-LED device, the recombination probability of holes and electrons can be increased to a certain extent, thereby improving the light-emitting efficiency of the Micro-LED device; therefore, the Micro-LED device provided by the present application can improve the working performance and working efficiency of the device to a certain extent. Brief Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a cross-sectional structure schematic diagram of the Micro-LED device provided by the embodiment of the present application;

[0031] Figure 2 It is a schematic flow diagram of a preparation method of the Micro-LED device provided by the embodiment of the present application. Detailed Embodiments

[0032] The core of the present invention is to provide a Micro-LED device, a preparation method of the Micro-LED device, and a head-mounted display device, which can improve the light-emitting efficiency and working performance of the Micro-LED device to a certain extent.

[0033] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0034] As Figure 1 shown, Figure 1 FIG. is a schematic cross-sectional structure diagram of the Micro-LED device provided by the embodiment of the present application; the Micro-LED device may include:

[0035] A light-emitting unit formed by sequentially stacking a substrate layer 1, an n-type GaN layer 2, a multi-quantum well active region layer 3, and a p-type GaN layer 4; an n-type electrode 7 penetrating the substrate layer 1 and extending to the n-type GaN layer 2;

[0036] Wherein, a p-type electrode layer 5 is covered on the surface of the p-type GaN layer 4 facing away from the multi-quantum well active region layer 3 and the side wall of the p-type GaN layer 4.

[0037] As Figure 1 shown, in the light-emitting unit, the n-type GaN layer 2 and the p-type GaN layer 4 are respectively distributed on both sides of the multi-quantum well active region layer 3. Correspondingly, the n-type electrode 7 and the p-type electrode layer 5 are also respectively disposed on the n-type GaN layer 2 and the p-type GaN layer 4; thus, when the n-type electrode 7 and the p-type electrode layer 5 are respectively connected to the supply voltage, a longitudinal electric field can be formed inside the light-emitting unit, thereby driving the recombination of electrons and holes, and thus exciting the multi-quantum well active region layer 3 to output light and emit light.

[0038] On this basis, in order to further improve the light-emitting efficiency of the light-emitting unit in this embodiment, while forming the p-type electrode layer 5 on the surface of the p-type GaN layer 4, the p-type electrode layer 5 not only covers the surface of the p-type GaN layer 4, but also further covers the sidewall surface of the p-type GaN layer 4, so that a transverse electric field can be generated in the p-type GaN layer 4 by the p-type electrode layer 5. During the actual operation of the Micro-LED device, the p-type electrode layer 5 is connected to the positive electrode of the supply voltage, which also makes the holes in the p-type GaN layer 4 more concentrated in the middle region of the p-type GaN layer 4; then this also enables the electrons driven by the longitudinal electric field generated between the n-type electrode 7 and the p-type electrode to better recombine with the holes in the p-type GaN layer 4, which can increase the light-emitting efficiency of the multi-quantum well active region layer 3 to a certain extent, and further improve the working performance of the entire Micro-LED device.

[0039] It can be understood that the Micro-LED device may include multiple light-emitting units similar to or the same as the above, or may only include one such light-emitting unit, which can be specifically set based on the actual application requirements of the Micro-LED device, and no specific limitation is made in this application.

[0040] Based on the above embodiment, further considering that the sidewalls of the light-emitting units in conventional Micro-LED devices are all columnar surfaces parallel to the vertical direction. And the light output from the multi-quantum well active region layer 3 in the light-emitting unit has light output from each of its surfaces. For the light with an incident angle greater than the critical angle at the sidewall interface of the multi-quantum well active region layer 3 among the light emitted by the multi-quantum well active region layer 3 cannot be output, but is restricted inside the Micro-LED and is finally absorbed after multiple reflections. For this reason, in order to further improve the light extraction rate of the light-emitting unit in this embodiment, during the process of etching to form the light-emitting unit, the sidewalls of the quantum well active region layer 3 can be set as inclined sidewalls, so that the two opposite sidewalls of the quantum well active region layer 3 are not parallel to each other; the probability that the incident angle of the light emitted by the multi-quantum well active region layer 3 at the sidewall interface of the multi-quantum well active region layer 3 is greater than the critical angle is reduced, and thus the proportion of the light output from the sidewalls of the multi-quantum well active region layer 3 can be increased, thereby improving the light extraction rate of the light-emitting unit to a certain extent.

[0041] As Figure 1 shown, in the embodiment shown in Figure 1 the inclined sidewalls of the sidewalls of the quantum well active region layer 3 can be inclined gradually from the n-type GaN layer 2 towards the center side of the quantum well active region layer 3 in the direction of the p-type GaN layer 4, but in actual applications, it does not exclude that the inclined sidewalls are inclined gradually from the n-type GaN layer 2 towards the side away from the center of the quantum well active region layer 3 in the direction of the p-type GaN layer 4.

[0042] In addition, as Figure 1 shown, in order to further reduce the difficulty of the processing technology, during the actual process of processing the side walls of the quantum well active region layer 3 into inclined side walls, the side walls of the n-type GaN layer 2 and the p-type GaN layer 4 on the upper and lower sides of the quantum well active region layer 3 can also be processed into inclined side walls, so that the three structural layers of the n-type GaN layer 2, the quantum well active region layer 3, and the p-type GaN layer 4 jointly form a square frustum or a conical frustum structure.

[0043] Of course, in practical applications, it is not excluded that only the side walls of one of the structural layers of the n-type GaN layer 2 and the p-type GaN layer 4 are processed into inclined side walls, or the side walls of both structural layers remain as columnar surfaces parallel to the vertical direction. In this embodiment, no specific restrictions are made on this, as long as the side walls of the quantum well active region layer 3 are conical surfaces as a whole.

[0044] Moreover, it can be understood that regardless of whether the side walls of the n-type GaN layer 2 and the p-type GaN layer 4 are inclined side walls, the surfaces between the two mutually attached surfaces of the quantum well active region layer 3 and the n-type GaN layer 2 should have the same shape and size; similarly, the surfaces between the two mutually attached surfaces of the quantum well active region layer 3 and the p-type GaN layer 4 should also have the same shape and size.

[0045] In addition, for the inclination angle formed by the side walls of the quantum well active region layer 3, it can be set that the angle with the vertical direction is not greater than 45°; for example, it can be 10°, 15°, 30°, 45°, etc. For the specific inclination angle of the inclined side walls, it can be set based on the wavelength of the light specifically generated by the quantum well active region layer 3. No specific restrictions are made in this application.

[0046] It can be understood that for the inclined side walls around the side of the quantum well active region layer 3, a unified inclination angle can be set, or different inclination angles can be set for the inclined side walls at different positions. For example, when the cross-section of the quantum well active region layer 3 is a rectangular cross-section, the quantum well active region layer 3 has four planar side walls. At this time, a pair of opposite side walls can be set as inclined side walls with an inclination angle of 10°, while the other pair of side walls can be set as inclined side walls with an inclination angle of 15°. No specific restrictions are made in this embodiment, and specifically, it can be set based on the actual application requirements of the Micro-LED device and the simplicity of the processing technology.

[0047] Based on any of the above embodiments, further considering that in a Micro-LED device, the light-emitting units are generally formed after preparing a large-area structural layer formed by sequentially stacking a substrate layer 1, an n-type GaN layer 2, a multi-quantum well active region layer 3, and a p-type GaN layer 4, and then patterning and etching the structural layer to form individual light-emitting units. However, during the etching process of forming the light-emitting units, it is often easy to cause etching damage to the sidewalls of the light-emitting units, introducing non-radiative recombination defects and reducing the working efficiency of the Micro-LED device.

[0048] Therefore, in another optional embodiment of the present application, an insulating layer 6 is further covered on the sidewalls of the multi-quantum well active region layer 3 and the n-type GaN layer 2.

[0049] The insulating layer 6 in this embodiment may include, but is not limited to, a silicon dioxide layer, an aluminum oxide layer, etc.

[0050] As Figure 1 shown, since during the process of forming the insulating layer 6 on the sidewalls of the light-emitting units, the insulating layer 6 inevitably covers the surface of the p-type electrode layer 5 on the sidewalls of the p-type GaN layer 4. That is, the insulating layer 6 can not only cover the sidewalls of the multi-quantum well active region layer 3 and the n-type GaN layer 2, but also extend to the surface of the p-type electrode layer 5 on the sidewalls of the p-type GaN layer 4. In practical applications, the insulating layer 6 on the surface of the p-type electrode layer 5 can be removed or retained, and in this regard, no limitation is made in this embodiment.

[0051] In summary, on the basis of covering and forming a p-type electrode layer on the surface of the p-type GaN layer, the present application further extends the p-type electrode layer to cover the sidewalls of the p-type GaN layer, so that the p-type electrode layer can form a lateral electric field in the p-type GaN layer, and further enables the holes in the p-type GaN layer to be more concentrated in the middle region of the p-type GaN layer, thereby increasing the recombination probability of holes and electrons, improving the light-emitting efficiency of the Micro-LED device, and being beneficial to the improvement of the working performance and working efficiency of the Micro-LED device.

[0052] Based on any of the above embodiments, the present application further provides a preparation method of a Micro-LED device, and this preparation method can be applied to prepare any of the above Micro-LED devices. As Figure 2 shown, Figure 2 is a schematic flow chart of a preparation method of a Micro-LED device provided by an embodiment of the present application.

[0053] In a specific embodiment of the present application, the preparation method of the Micro-LED device may include:

[0054] S1: Generate a light-emitting unit including a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer stacked in sequence.

[0055] It can be understood that when preparing the light-emitting units in a Micro-LED device, generally a large number of light-emitting units are formed in a batch manner. In the actual process of forming the light-emitting units, metal organic chemical vapor deposition (MOCVD) technology can be used to sequentially stack and form an n-type GaN layer 2, a multi-quantum well active region layer 3, and a p-type GaN layer structural layer 4 on the substrate layer 1; then pattern etch the structural layer to form the light-emitting units.

[0056] It can be understood that when forming each layer structure in the structural layer, an n-type GaN layer 2, a multi-quantum well active region layer 3, and a p-type GaN layer 4 with the same large area size can be sequentially stacked and prepared on a substrate layer with a relatively large area. On this basis, a relatively large-area structural layer can be etched through to form a number of light-emitting units with a large quantity and basically the same structure.

[0057] Optionally, further considering that during the process of etching to form the light-emitting units, if the sidewall of the light-emitting unit is a columnar surface parallel to the vertical direction; there is a part of the light generated in the multi-quantum well active region layer 3 that undergoes total internal reflection on the sidewall of the multi-quantum well active region layer 3 and is restricted to be repeatedly reflected inside the light-emitting unit and finally absorbed without being output for utilization. Therefore, in this embodiment, in order to further improve the light extraction efficiency of the light generated in the light-emitting unit, when etching to form the light-emitting units, the sidewalls of at least the multi-quantum well active region layer 3 in the n-type GaN layer 2, the multi-quantum well active region layer 3, and the p-type GaN layer 4 of the light-emitting unit can be etched to form inclined sidewalls, and the angle between the inclined sidewalls and the vertical direction can be no more than 45°; thereby reducing the proportion of the light intensity that undergoes total internal reflection in the multi-quantum well active region layer 3 among the light generated in the multi-quantum well active region layer 3, and further enabling a greater degree of the light incident on the sidewall of the multi-quantum well active region layer 3 to be output from the sidewall, that is, improving the light extraction efficiency of the light-emitting unit.

[0058] S2: Form a p-type electrode layer 5 on the surface of the p-type GaN layer 4 facing away from the multi-quantum well active region layer 2 and on the sidewalls of the p-type GaN layer 4.

[0059] It should be noted that during the etching process of forming the light-emitting unit, etching damage will inevitably occur to the sidewalls of the n-type GaN layer 2, the multi-quantum well active region layer 3, and the p-type GaN layer 4 in the light-emitting unit, thereby introducing non-radiative recombination defects. Therefore, in this embodiment, when forming the p-type electrode layer 5, the p-type electrode layer 5 not only covers the surface of the p-type GaN layer 4, but also further covers the sidewalls of the p-type GaN layer 4. Thus, the p-type electrode layer 5 covering the sidewalls of the p-type GaN layer 4 can form a lateral electric field in the p-type GaN layer 4, driving the holes in the p-type GaN layer 4 away from the sidewalls and concentrating in the central region of the p-type GaN layer 4. Thereby, the non-radiative recombination defects in the p-type GaN layer 4 can be eliminated to a certain extent, the recombination probability of holes and electrons in the p-type GaN layer 4 can be increased, and the working efficiency and performance of the Micro-LED device can be improved to a certain extent.

[0060] In addition, the p-type electrode layer 5 can be formed on the p-type GaN layer 4 by techniques such as electron beam evaporation or magnetron sputtering. However, when actually processing to form the p-type electrode layer 4 covering the sidewalls of the p-type GaN layer 4, it is often impossible to accurately form the p-type electrode layer 5 only for the sidewalls of the p-type GaN layer 4, but the sidewalls of the three-layer structure of the n-type GaN layer 2, the multi-quantum well active region layer 3, and the p-type GaN layer 4 in the light-emitting unit will all form the p-type electrode layer 5. Therefore, generally after forming the p-type electrode layer 5 on the sidewalls of the light-emitting unit, the p-type electrode layer 5 on the sidewalls of the multi-quantum well active region layer 3 and the p-type GaN layer 4 should be further etched and removed, and then only the p-type electrode layer 5 on the sidewalls of the p-type GaN layer 4 is retained.

[0061] As described above, covering the sidewalls of the p-type GaN layer 4 with the p-type electrode layer 5 can only eliminate the defect damage caused by etching in the p-type GaN layer 4. In another optional embodiment of the present application, after forming the above p-type electrode layer 5, an insulating layer 6 can be further formed on the sidewalls of the n-type GaN layer 2 and the multi-quantum well active region layer 3. Specifically, the insulating layer 6 similar to a structural layer such as a silicon dioxide layer or an aluminum oxide layer can be formed on the sidewalls of the n-type GaN layer 2 and the multi-quantum well active region layer 3 by means of precipitation or the like.

[0062] Similar to forming the p-type electrode layer 5 on the sidewalls of the p-type GaN layer 4, when forming the insulating layer on the sidewalls of the n-type GaN layer 2 and the multi-quantum well active region layer 3, the insulating layer 6 will also be formed on the p-type electrode layer 5 on the sidewalls of the p-type GaN layer 4. For the insulating layer 6 on the p-type electrode layer 5 on the sidewalls of the p-type GaN layer, it can be removed by etching or retained, and no specific limitation is made in this application.

[0063] S3: Prepare and form a substrate layer that penetrates the light-emitting unit and extends to the n-type electrode of the n-type GaN layer.

[0064] In the process of forming the n-type electrode 7, an electrode hole penetrating the substrate layer 1 and extending to the n-type GaN layer 2 can be first formed by etching; then the n-type electrode 7 is formed in the electrode hole.

[0065] In practical applications, the substrate layer 1 can use a sapphire substrate with a relatively large thickness. In order to further simplify the difficulty of preparing the n-type electrode 7 and reduce the overall thickness of the Micro-LED device, before forming the n-type electrode 7, the substrate layer can also be etched and thinned first, that is, etching is performed from the surface of the substrate layer facing away from the n-type GaN layer 2, and only a substrate layer 1 with a set thickness is retained. The set thickness can be artificially set according to actual needs, and no specific limitation is made in this application.

[0066] After the substrate layer 1 is etched and thinned, the electrode hole can be processed and the n-type electrode 7 can be further prepared.

[0067] Based on the above discussion, in the process of processing and manufacturing the Micro-LED device in this application, on the basis of forming a p-type electrode on the entire surface of the p-type GaN layer in each light-emitting unit facing away from the multi-quantum well active region layer, the p-type electrode is further extended to cover the side wall of the p-type GaN layer, so that the holes in the p-type GaN layer are far away from the side wall and concentrated in the middle region of the p-type GaN layer, improving the recombination probability of holes and electrons in the p-type GaN layer. Thus, the non-radiative recombination defects in the p-type GaN layer can be eliminated to a certain extent, and the working efficiency and working performance of the Micro-LED device can be improved to a certain extent.

[0068] This application also provides an embodiment of a head-mounted display device. The head-mounted display device can include the Micro-LED device described in any one of the above, and an optical element disposed on the output optical path of the Micro-LED device.

[0069] The Micro-LED device in this embodiment outputs light as a light source device in the head-mounted display device and is conducted and output through the optical element; and the Micro-LED device in this embodiment can be an AR display device or a VR display device, or can also be other types of display devices, and no specific limitation is made in this application.

[0070] The head-mounted display device in this embodiment adopts the Micro-LED device described in any one of the above, which can improve the working efficiency and working performance of the light source device to a certain extent, and further improve the working performance of the head-mounted display device.

[0071] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that the elements inherent in a process, method, article or device including a series of elements. Without more limitations, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element. In addition, the parts of the above technical solutions provided by the embodiments of the present application that are consistent with the corresponding technical solutions in the prior art are not described in detail to avoid excessive elaboration.

[0072] Specific examples are used in this article to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A Micro-LED device, characterized in that, Comprising: A light-emitting unit formed by sequentially stacking a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer; An n-type electrode penetrating the substrate layer and extending to the n-type GaN layer; Wherein, a p-type electrode layer is disposed to cover the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and the sidewalls of the p-type GaN layer.

2. The Micro-LED device according to claim 1, wherein, The sidewalls of the multi-quantum well active region layer are inclined sidewalls.

3. The Micro-LED device according to claim 2, wherein, The n-type GaN layer, the multi-quantum well active region layer, and the p-type GaN layer together form a frustum of a cone or a frustum of a square pyramid.

4. The Micro-LED device according to claim 2, wherein, The angle between the inclined sidewall and the vertical direction is not greater than 45°.

5. The Micro-LED device according to claim 1, characterized in that, The sidewalls of the multi-quantum well active region layer and the n-type GaN layer are covered with an insulating layer.

6. A method for preparing a Micro-LED device, characterized in that, For preparing the Micro-LED device according to any one of claims 1 to 5, the preparation method includes: Generating a light-emitting unit including a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer stacked in sequence; Forming a p-type electrode layer to cover the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and the sidewalls of the p-type GaN layer; Preparing and forming an n-type electrode that penetrates the substrate layer of the light-emitting unit and extends to the n-type GaN layer.

7. The manufacturing method of the Micro-LED device according to claim 6, characterized in that, Generating a light-emitting unit including a substrate layer, an n-type GaN layer, a multi-quantum well active region layer, and a p-type GaN layer stacked in sequence, including: Sequentially stacking a structure layer including the n-type GaN layer, the multi-quantum well active region layer, and the p-type GaN layer on the substrate layer; Patterning and etching the structure layer to form the light-emitting unit, wherein at least the sidewalls of the multi-quantum well active region layer in each light-emitting unit are etched into inclined sidewalls.

8. The manufacturing method of the Micro-LED device according to claim 6, characterized in that, Forming a p-type electrode layer to cover the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and the sidewalls of the p-type GaN layer, including: Forming a P-type electrode layer on the surface of the p-type GaN layer facing away from the multi-quantum well active region layer, and on the sidewalls of the n-type GaN layer, the multi-quantum well active region layer, and the p-type GaN layer; Etching and removing the P-type electrode layer on the sidewalls of the n-type GaN layer and the multi-quantum well active region layer.

9. The manufacturing method of the Micro-LED device according to claim 6, characterized in that, After forming a p-type electrode layer to cover the surface of the p-type GaN layer facing away from the multi-quantum well active region layer and the sidewalls of the p-type GaN layer, it further includes: Forming an insulating layer on the sidewalls of the n-type GaN layer and the multi-quantum well active region layer.

10. The manufacturing method of the Micro-LED device according to claim 6, characterized in that, Preparing and forming an n-type electrode that penetrates the substrate layer of the light-emitting unit and extends to the n-type GaN layer, including: Etching and thinning the substrate layer to obtain a substrate layer not greater than a set thickness; Preparing and forming an n-type electrode that penetrates the etched substrate layer and extends to the n-type GaN layer.

11. A head-mounted display device, characterized in that, Including the Micro-LED device according to any one of claims 1 to 5, and an optical element disposed on the output optical path of the Micro-LED device.

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