Micro-LED with high light extraction rate and preparation method thereof

Abstract

The invention discloses the field of semiconductor Micro-LED display, and particularly relates to a Micro-LED with a high light extraction rate and a preparation method thereof.The Micro-LED with the high light extraction rate comprises a substrate (1), an epitaxial wafer (2) is arranged on the substrate (1), a plurality of nano holes (3) are formed in the top of the epitaxial wafer (2), a plurality of spherical particles (4) are arranged in the nano holes (3) in a one-to-one correspondence mode, and the spherical particles (4) are arranged in the epitaxial wafer (2) in a one-to-one correspondence mode. According to the micro-LED epitaxial wafer, the nanopores are etched in the top of the epitaxial wafer, the spherical particles are embedded into the nanopores, the propagation path of light is changed by arranging the spherical particles, the refraction and reflection efficiency of the light is improved, the Plasma effect is further enhanced, and therefore the light extraction efficiency of the micro-LED is remarkably improved, and the service life of the micro-LED is prolonged. The method is simple to operate and high in adaptability, can be applied to Micro-LED devices of various sizes and types, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor Micro-LED display, and in particular to a Micro-LED with high light extraction rate and a preparation method thereof. Background Art

[0002] LED has the advantages of high brightness, high light efficiency, long life, high contrast, and nanosecond response time. At the same time, LED is prepared using semiconductor processing technology and is compatible with IC technology. It has extremely high device processing accuracy and stability, and is expected to achieve ultra-high resolution, which is convenient for integration with sensors such as touch, hearing, and smell, to achieve high-precision spatial positioning and tactile perception, making more realistic AR and VR possible. Ultra-high-resolution Micro-LED light-emitting display refers to extremely high-resolution LED display technology with nano-level pixels. As display terminals have higher and higher requirements for the amount of displayed information and functional integration, ultra-high-resolution Micro-LED light-emitting display is an inevitable trend in the development of display technology. However, there are many scientific and technological problems in ultra-high-resolution Micro-LED light-emitting display, which urgently need new response strategies and transformative technologies to solve.

[0003] Micro-LED can make high resolution easier to achieve, such as 4K or even 8K resolution smartphones or virtual reality screens. However, Micro-LED is a point light source and its light emission has the characteristics of a point light source. How to extract and utilize more light during use is a problem.

[0004] Therefore, technicians in this field are committed to developing a Micro-LED with high light extraction rate and a preparation method thereof, which can significantly enhance the Plasmonic effect while maintaining stable electrical performance, thereby improving light extraction efficiency. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a Micro-LED with high light extraction efficiency and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the present invention provides a Micro-LED with high light extraction rate, including a substrate, an epitaxial wafer is provided on the substrate, a plurality of nanoholes are opened on the top of the epitaxial wafer, a plurality of spherical particles are provided in the plurality of nanoholes, and the plurality of spherical particles are wrapped with insulating material.

[0007] Preferably, the epitaxial wafer includes a P-GAN layer, a MQW layer and an N-GAN layer arranged in sequence from bottom to top.

[0008] Preferably, the nanopore is connected to the MQW layer.

[0009] Preferably, the spherical particles are made of Ag.

[0010] Preferably, the diameter of some of the spherical particles is 3nm-15nm.

[0011] Preferably, the insulating material is silicon dioxide, silicon nitride or aluminum oxide.

[0012] The present invention also provides a method for preparing a Micro-LED with a high light extraction rate, comprising the following steps:

[0013] S1, etching defines the Micro-LED table;

[0014] S2, opening a number of nanoholes on the top of the table;

[0015] S3, preparing spherical particles, and performing insulation treatment on the spherical particles;

[0016] S4. Place a number of spherical particles after insulation treatment into the nanopore.

[0017] Preferably, in step S3, silicon dioxide, silicon nitride or aluminum oxide may be coated outside the spherical particles.

[0018] Preferably, in step S4, the spherical particles are made of gold, silver or aluminum.

[0019] The beneficial effects of the present invention are as follows: the present invention etches nanoholes on the top of the epitaxial wafer and embeds spherical particles in the nanoholes, and changes the propagation path of light by arranging the spherical particles, thereby improving the refraction and reflection efficiency of light, and further enhancing the Plasmonic effect, thereby significantly improving the light extraction efficiency of Micro-LED. The method is simple to operate, has strong adaptability, can be applied to Micro-LED devices of various sizes and types, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of an epitaxial wafer in a specific implementation manner of the present invention.

[0021] Figure 2 It is a schematic diagram of the structure of the opening at the top of the epitaxial wafer in a specific implementation manner of the present invention.

[0022] Figure 3 It is a schematic diagram of the assembly of epitaxial wafers and spherical particles in a specific embodiment of the present invention.

[0023] Figure 4 It is a schematic diagram of the structure of spherical particles in a specific embodiment of the present invention.

[0024] 1. Substrate; 2. Epitaxial wafer; 21. P-GAN layer; 22. MQW layer; 23. N-GAN layer; 3. Nanopores; 4. Spherical particles; 5. Insulating material. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific manner, and therefore cannot be understood as limiting the present invention. The terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0026] like Figure 1-3 As shown, a Micro-LED with high light extraction rate includes a substrate 1, an epitaxial wafer 2 is arranged on the substrate 1, and the epitaxial wafer 2 includes a P-GAN layer 21, an MQW layer 22 and an N-GAN layer 23 arranged in sequence from bottom to top. A plurality of nanoholes 3 are opened on the top of the N-GAN layer 23. In this embodiment, the bottoms of the plurality of nanoholes 3 are connected to the MQW layer 22. A plurality of spherical particles 4 are arranged in the plurality of nanoholes 3. The diameter of the plurality of spherical particles 4 is 3nm-15nm. Because the wavelength band of the spherical particles 4 absorbing light should be enhanced, the spherical particles 4 should have high reflectivity and no absorption within the working wavelength range. The metal material for collecting photons, in this embodiment, the spherical particles 4 are made of Ag, and other materials that can enhance the Plasmonic effect, such as gold (Au) or aluminum (Al), can also be used in other embodiments. Some spherical particles 4 are wrapped with an insulating material 5, and in this example, the insulating material 5 is made of silicon dioxide, and other insulating materials such as SiN, Al2O3, etc. can also be used in other embodiments. By wrapping the spherical particles 4 with insulating materials to keep them in an insulating state, the stability of the structure and the maintenance of electrical properties are ensured, and the short circuit problem caused by the contact between the metal and the LED electrode is effectively avoided.

[0027] When in use: a nanohole 3 is etched on the top of the epitaxial wafer 2, and spherical particles 4 are embedded in the nanohole 3. The spherical particles 4 are arranged to change the propagation path of light, improve the refraction and reflection efficiency of light, and further enhance the Plasmonic effect, thereby significantly improving the light extraction efficiency of the Micro-LED. This method is simple to operate and has strong adaptability. It can be applied to Micro-LED devices of various sizes and types and has broad application prospects.

[0028] The present invention also provides a method for preparing a Micro-LED with a high light extraction rate, comprising the following steps:

[0029] S1. Define the Mesa structure in the p-type and n-type regions of the semiconductor LED through ICP etching technology, such as Figure 1 As shown, the formation of this structure helps to improve the light emission efficiency and provides a basis for subsequent processes;

[0030] S2, such as Figure 2 As shown, a plurality of nanopores 3 are opened on the top of the table by electrochemical methods or other high-precision etching techniques, thereby forming a precise nanopore 3 structure. In this embodiment, the diameters of the nanopores 3 are the same. In other embodiments, the diameters of the nanopores 3 may be random or different. The opening design can effectively adjust the propagation path of the incident light.

[0031] S3, such as Figure 3-4 As shown, a number of spherical particles 4 corresponding to the nanopores 3 are prepared, and an insulating material 5 is wrapped outside the spherical particles 4. In this embodiment, the insulating material 5 is silicon dioxide. By wrapping the insulating material 5 outside the spherical particles 4 to insulate them, short circuit of the structure is prevented and its stability is protected, while avoiding the short circuit problem caused by the contact between the metal and the LED electrode.

[0032] S4. Place the spherical particles 4 wrapped with insulating material 5 in a plurality of nanoholes 3 one by one, and put the spherical particles 4 into the bottom of the nanoholes 3 in contact with the MQW layer 22 to ensure that they are fully fitted with the emitting light source, thereby maximizing the Plasmonic effect. Because the wavelength band of light absorption by the spherical particles 4 needs to be enhanced, a metal material with high reflectivity within the working wavelength range and that does not absorb photons should be selected. In this embodiment, Ag is selected as the material of the spherical particles 4. In other embodiments, metals such as Au and Al that can produce a strong Plasmonic effect can also be used to achieve maximum light extraction efficiency.

[0033] After the spherical particles 4 are embedded in the nanopores 3, a closer coupling relationship is formed with the Micro-LED light-emitting structure. The Plasmonic effect can be significantly enhanced in this structure, and the local electromagnetic field intensity of the light on the surface of the spherical particles 4 is further improved, thereby greatly improving the light extraction efficiency.

[0034] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A Micro-LED with high light extraction efficiency, characterized by: The invention comprises a substrate (1), wherein an epitaxial wafer (2) is provided on the substrate (1), a plurality of nano-holes (3) are opened on the top of the epitaxial wafer (2), a plurality of spherical particles (4) are provided in the plurality of nano-holes (3), and the plurality of spherical particles (4) are wrapped with insulating material (5).

2. The Micro-LED with high light extraction efficiency as claimed in claim 1, characterized in that: The epitaxial wafer (2) comprises a P-GAN layer (21), an MQW layer (22) and an N-GAN layer (23) which are arranged in sequence from bottom to top.

3. The Micro-LED with high light extraction efficiency as claimed in claim 1, characterized in that: The nanopore (3) is connected to the MQW layer (22).

4. The Micro-LED with high light extraction efficiency as claimed in claim 1, characterized in that: The spherical particles (4) are made of Ag.

5. The Micro-LED with high light extraction efficiency as claimed in claim 1, characterized in that: The diameter of some of the spherical particles (4) is 3nm-15nm.

6. The Micro-LED with high light extraction efficiency as claimed in claim 1 or 4, characterized in that: The insulating material (5) is silicon dioxide.

7. A method for preparing a Micro-LED with high light extraction efficiency, characterized in that: The following steps are involved: S1, etching defines the Micro-LED table; S2, opening a number of nanoholes (3) on the top of the table; S3, preparing spherical particles (4), and performing insulation treatment on the spherical particles (4); S4. Place a number of spherical particles (4) that have been subjected to insulation treatment into the nanopore (3).

8. The method for preparing a Micro-LED with high light extraction efficiency as claimed in claim 7, characterized in that: In step S3, silicon dioxide, silicon nitride or aluminum oxide or the like may be coated outside the spherical particles (4).

9. The method for preparing a Micro-LED with high light extraction efficiency as claimed in claim 7, characterized in that: In step S4, the spherical particles (4) are made of gold, silver or aluminum.

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