A Micro LED chip with high consistency and a manufacturing method thereof

Abstract

The present invention relates to the technical field of Micro LED chips, and discloses a highly consistent Micro LED chip, which includes a substrate and a GaN-based epitaxial wafer disposed on the substrate. The GaN-based epitaxial wafer is sequentially provided with an N-type GaN layer, a light-emitting quantum well layer, and a P-type GaN layer from bottom to top. An N-type electrode layer is plated on the N-type GaN layer, and a P-type electrode layer is plated on the P-type GaN layer. The GaN-based epitaxial wafer is provided with a plurality of isolation grooves distributed in a crisscross manner. The isolation grooves divide the GaN-based epitaxial wafer into a plurality of light-emitting units arranged in a matrix array. The isolation grooves are located above the N-type GaN layer and expose the top surface of the N-type GaN layer. The exposed top surface of the N-type GaN layer in the isolation groove is plated with a built-in N-type electrode layer integrally formed with the N-type electrode layer, and the side of the built-in N-type electrode layer is separated from the light-emitting unit. At the same time, the present invention also discloses a manufacturing method of the chip. By adopting the present invention, the setting of the built-in N-type electrode layer enables the current to be evenly distributed when diffusing in the N-type GaN layer, thereby ensuring that the brightness of each light-emitting unit is consistent when emitting light.

Description

Technical Field

[0001] The present invention relates to the technical field of Micro LED chips, and particularly to a high-consistency Micro LED chip and a manufacturing method thereof. Background Art

[0002] Micro LED technology, namely LED miniaturization and matrix technology, refers to a high-density and small-size LED array integrated on a chip. For example, each pixel of an LED display can be addressed and individually driven to light up, which can be regarded as a miniaturized version of an outdoor LED display, reducing the distance between light-emitting units from millimeters to micrometers. Currently, Micro LED chips generally adopt a process with a common N electrode, and the P electrode is individually driven to control the lighting of each light-emitting unit. When the Micro LED chip works, the current needs to flow back from the N pole of the Micro LED chip to the negative pole of the power supply. Since the Micro LED chip has a common N electrode, the current will spread in the epitaxial layer. Due to the poor conductivity of the epitaxial layer, there may be a problem of inconsistent brightness when the light-emitting units near the N electrode and those far from the N electrode are lit. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a high-consistency Micro LED chip and a manufacturing method thereof that ensure the same luminous brightness of each light-emitting unit.

[0004] To solve the above technical problem, the present invention provides a high-consistency Micro LED chip, including a substrate and a GaN-based epitaxial wafer disposed on the substrate. The GaN-based epitaxial wafer is sequentially provided with an N-type GaN layer, a light-emitting quantum well layer, and a P-type GaN layer from bottom to top. An N-type electrode layer is plated on the N-type GaN layer, and a P-type electrode layer is plated on the P-type GaN layer. It is characterized in that: the GaN-based epitaxial wafer is provided with a plurality of isolation grooves distributed in a crisscross manner, the isolation grooves divide the GaN-based epitaxial wafer into a plurality of light-emitting units arranged in a matrix array, the isolation grooves are located above the N-type GaN layer and expose the top surface of the N-type GaN layer, and an internal N-type electrode layer integrally formed with the N-type electrode layer is plated on the exposed top surface of the N-type GaN layer in the isolation grooves, and the side of the internal N-type electrode layer is separated from the light-emitting unit.

[0005] As a preferred embodiment of the present invention, a step is provided on the N-type GaN layer, and the light-emitting unit is disposed on the step.

[0006] As a preferred embodiment of the present invention, a protective layer is provided on the light-emitting unit, and a conductive channel exposing the P-type electrode layer is provided on the protective layer, and the internal N-type electrode layer is covered by the protective layer.

[0007] As a preferred embodiment of the present invention, the P-type electrode layer protrudes from the P-type GaN layer through the conductive channel.

[0008] As a preferred embodiment of the present invention, the height of the built-in N-type electrode layer is flush with the light-emitting quantum well layer.

[0009] As a preferred embodiment of the present invention, an ITO layer is provided between the P-type GaN layer and the P-type electrode layer.

[0010] As a preferred embodiment of the present invention, the substrate is a sapphire substrate.

[0011] Meanwhile, the present invention also provides a method for manufacturing a high-consistency Micro LED chip, comprising the following steps:

[0012] (1) Fabricate a GaN-based epitaxial wafer, and sequentially deposit an N-type GaN layer, a light-emitting quantum well layer, and a P-type GaN layer from bottom to top on the substrate by using an MOCVD device to form a GaN-based epitaxial wafer;

[0013] (2) Etch a plurality of intersecting isolation grooves on the GaN-based epitaxial wafer to expose the top surface of the N-type GaN layer, and at the same time divide the GaN-based epitaxial wafer into a plurality of light-emitting units arranged in a matrix array;

[0014] (3) Deposit an N-type electrode layer and a built-in N-type electrode layer on the N-type GaN layer, wherein the built-in N-type electrode layer is disposed in the isolation groove and the side of the N-type electrode layer is separated from the light-emitting unit;

[0015] (4) Deposit an ITO layer on the P-type GaN layer of the light-emitting unit;

[0016] (5) Deposit a protective layer made of SiO2 material on the light-emitting unit, wherein the protective layer covers the built-in electrode layer;

[0017] (6) Etch a P conductive channel on the protective layer to expose the ITO layer;

[0018] (7) Evaporate a P-type electrode layer in the conductive channel.

[0019] Implementing a highly consistent Micro LED chip and its manufacturing method provided by the present invention, compared with the prior art, the beneficial effects are as follows: Due to the setting of the built-in N-type electrode layer, when the current expands in the N-type GaN layer, the current can be transmitted through the N-type electrode layer, making the current distribution in the N-type GaN layer more uniform, and finally making the brightness of each light-emitting unit consistent when it is lit; in addition, the built-in N-type electrode layer can play a role in blocking the side light of the light-emitting unit, effectively improving the drawback of sidewall light leakage when the light-emitting unit is lit alone. Brief Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of the present invention;

[0021] Figure 2 is a schematic cross-sectional structural principle diagram of the present invention;

[0022] In the figure, 1, substrate; 2, GaN-based epitaxial wafer; 21, N-type GaN layer; 22, light-emitting quantum well layer; 23, P-type GaN layer; 24, light-emitting unit; 25, isolation groove; 26, ITO layer; 3, N-type electrode layer; 4, built-in N-type electrode layer; 5, P-type electrode layer; 6, protective layer; 61, conductive channel. Detailed Embodiments

[0023] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0024] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. in the present invention is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be understood that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] As shown Figure 1 In FIG. -2, a highly consistent Micro LED chip according to a preferred embodiment of the present invention includes a substrate 1 and a GaN-based epitaxial wafer 2 disposed on the substrate 1. The GaN-based epitaxial wafer 2 is sequentially provided with an N-type GaN layer 21, a light-emitting quantum well layer 22, and a P-type GaN layer 23 from bottom to top. An N-type electrode layer 3 is plated on the N-type GaN layer 21, and a P-type electrode layer 5 is plated on the P-type GaN layer 23. The GaN-based epitaxial wafer 2 is provided with a plurality of isolation grooves 25 distributed in a crisscross manner. The isolation grooves 25 divide the GaN-based epitaxial wafer 2 into a plurality of light-emitting units 24 arranged in a matrix array. The isolation grooves 25 are located above the N-type GaN layer 21 and expose the top surface of the N-type GaN layer 21. An internal N-type electrode layer 4 integrally formed with the N-type electrode layer 3 is plated on the exposed top surface of the N-type GaN layer 21 in the isolation grooves 25. The side of the internal N-type electrode layer 4 is separated from the light-emitting unit 24. The P-type electrode layer 5 is respectively disposed on the P-type GaN layer 23 of each light-emitting unit 24.

[0027] The working principle of the present invention is as follows: The P-type electrode layer 5 is connected to the positive electrode of the power supply, and the N-type electrode layer 3 is connected to the negative electrode of the power supply. The current sequentially passes through the P-type GaN layer 23, the light-emitting quantum well layer 22, and the N-type GaN layer 21. The current is transmitted through the internal N-type electrode layer 4, so that the current is evenly distributed when diffusing in the N-type GaN, so that the light-emitting brightness can be kept consistent regardless of the distance between the light-emitting unit 24 and the negative electrode of the power supply. In addition, the internal N-type electrode layer 4 can play a role in blocking the side light of the light-emitting unit 24, effectively improving the disadvantage of sidewall light leakage when the light-emitting unit 24 is lit alone.

[0028] Exemplarily, the N-type GaN layer 21 is provided with a step, and the light-emitting unit 24 is disposed on the step, so that the N-type GaN layer 21 is thickened at the position corresponding to the light-emitting unit 24, which helps the diffusion of the current.

[0029] Exemplarily, a protective layer 6 is provided on the light-emitting unit 24, and a conductive channel 61 exposing the P-type electrode layer 5 is provided on the protective layer 6. The internal N-type electrode layer 4 is covered by the protective layer 6. The P-type electrode layer 5 protrudes from the P-type GaN layer 23 through the conductive channel 61. The protective layer 6 protects the light-emitting unit 24 and the internal N-type electrode layer 4. The protrusion of the P-type electrode layer 5 facilitates the connection of the P-type electrode layer 5 to the power supply.

[0030] Exemplarily, the height of the internal N-type electrode layer 4 is flush with the light-emitting quantum well layer 22, which can block the light emitted from the side of the light-emitting quantum well layer 22 and effectively prevent sidewall light leakage of the light-emitting unit 24.

[0031] Exemplarily, an ITO layer 26 (ITO is indium tin oxide) is provided between the P-type GaN layer 23 and the P-type electrode layer 5, which helps to improve the conductivity of the P-type GaN layer 23.

[0032] Exemplarily, substrate 1 is a sapphire substrate having stable chemical properties.

[0033] The method for manufacturing a highly consistent Micro LED chip based on the above contents includes the following steps:

[0034] (1) manufacturing a GaN-based epitaxial wafer 2, using a MOCVD device to sequentially deposit an N-type GaN layer 21, a light-emitting quantum well layer 22, and a P-type GaN layer 23 on a substrate 1 from bottom to top, thereby forming a GaN-based epitaxial wafer 2;

[0035] (2) etching a plurality of isolation grooves 25 distributed in a crisscross pattern on the GaN-based epitaxial wafer 2 to expose the top surface of the N-type GaN layer 21, and dividing the GaN-based epitaxial wafer 2 into a plurality of light-emitting units 24 arranged in a matrix array;

[0036] (3) vapor-depositing an N-type electrode layer 3 and an internal N-type electrode layer 4 on the N-type GaN layer 21, wherein the internal N-type electrode layer 4 is disposed in the isolation groove 25 and the side of the N-type electrode layer 3 is separated from the light-emitting unit 24;

[0037] (4) Plating an ITO layer 26 on the P-type GaN layer 23 of the light-emitting unit 24;

[0038] (5) depositing a protective layer 6 of SiO2 material on the light-emitting unit 24, wherein the protective layer 6 covers the built-in electrode layer;

[0039] (6) etching a conductive channel 61 on the protective layer 6 to expose the ITO layer 26;

[0040] (7) A P-type electrode layer 5 is evaporated in the conductive channel 61 .

[0041] In summary, the highly consistent Micro LED chip of the present invention, due to the configuration of the built-in N-type electrode layer 4, makes the current diffuse more evenly in the N-type GaN layer 21, so that the brightness of each light-emitting unit 24 remains consistent when emitting light.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A manufacturing method of a highly consistent Micro LED chip, characterized in that: The highly consistent Micro LED chip includes a substrate and a GaN-based epitaxial wafer disposed on the substrate. The GaN-based epitaxial wafer is sequentially provided with an N-type GaN layer, a light-emitting quantum well layer, and a P-type GaN layer from bottom to top. An N-type electrode layer is plated on the N-type GaN layer, and a P-type electrode layer is plated on the P-type GaN layer. It is characterized in that: the GaN-based epitaxial wafer is provided with a plurality of isolation grooves distributed in a crisscross manner. The isolation grooves divide the GaN-based epitaxial wafer into a plurality of light-emitting units arranged in a matrix array. The isolation grooves are located above the N-type GaN layer and expose the top surface of the N-type GaN layer. An internal N-type electrode layer integrally formed with the N-type electrode layer is plated on the exposed top surface of the N-type GaN layer in the isolation grooves. The side of the internal N-type electrode layer is separated from the light-emitting unit. The height of the internal N-type electrode layer is flush with the light-emitting quantum well layer; The manufacturing method of the highly consistent Micro LED chip includes the following steps: (1). Fabricate a GaN-based epitaxial wafer, and sequentially deposit an N-type GaN layer, a light-emitting quantum well layer, and a P-type GaN layer on the substrate from bottom to top by using MOCVD equipment to form a GaN-based epitaxial wafer; (2). Etch a plurality of isolation grooves distributed in a crisscross manner on the GaN-based epitaxial wafer to expose the top surface of the N-type GaN layer, and at the same time divide the GaN-based epitaxial wafer into a plurality of light-emitting units arranged in a matrix array; (3). Plate an N-type electrode layer and an internal N-type electrode layer on the N-type GaN layer, wherein the internal N-type electrode layer is disposed in the isolation grooves and the side of the N-type electrode layer is separated from the light-emitting unit; (4). Plate an ITO layer on the P-type GaN layer of the light-emitting unit; (5). Deposit a protective layer made of SiO2 material on the light-emitting unit, wherein the protective layer covers the internal electrode layer; (6). Etch a P conductive channel on the protective layer to expose the ITO layer; (7). Evaporate and deposit a P-type electrode layer in the conductive channel.

2. The manufacturing method of the highly consistent Micro LED chip according to claim 1, wherein: Steps are provided on the N-type GaN layer, and the light-emitting units are disposed on the steps.

3. The manufacturing method of the highly consistent Micro LED chip according to claim 1, characterized in that: The substrate is a sapphire substrate.

Images