CN221239643U

CN221239643U - Graphical composite substrate and epitaxial structure thereof

Info

Publication number: CN221239643U
Application number: CN202221350781.3U
Authority: CN
Inventors: 付星星; 孙帅; 芦玲
Original assignee: Huaian Aucksun Optoelectronics Technology Co Ltd
Current assignee: Huaian Aucksun Optoelectronics Technology Co Ltd
Filing date: 2022-06-01
Publication date: 2024-06-28
Anticipated expiration: 2032-06-01

Abstract

The utility model relates to the field of semiconductors, and discloses a patterned composite substrate and an epitaxial structure thereof, wherein the patterned composite substrate comprises a substrate body (1) with a micron-sized periodically arranged convex structure (101) on the surface, isolation grooves (103) are arranged between adjacent convex structures, and the whole surface of the convex structure is distributed with a nanoscale microstructure (102) which consists of an upper cylinder microstructure (1021) made of silicon dioxide and a lower cylinder microstructure (1022) which is an integral structure with the convex structure and is made of the same material. The nano-scale microstructure in the substrate is equivalent to increasing the density of the raised structures and the reflective surface area of the raised structures, and the upper microstructure is designed to be made of silicon dioxide material, so that the reflectivity of the substrate can be further improved, and the light emitting efficiency of the LED device is improved; the C-surface patterning duty ratio of the substrate is increased, so that the lateral epitaxial effect is improved, and the internal quantum efficiency of the LED device is improved.

Description

Graphical composite substrate and epitaxial structure thereof

Technical Field

The utility model relates to the technical field of semiconductors, in particular to a graphical composite substrate with a micro-nano structure and an epitaxial structure thereof.

Background

Semiconductor light-emitting diodes (LEDs) have the advantages of small volume, low energy consumption, long service life, environmental protection, durability and the like, and blue and green light GaN-based LED chips rapidly develop in the fields of display and illumination; domestic LED illumination has replaced common illumination by about 30% and in order to continue to improve the popularity of LEDs in the illumination market, the performance of the LEDs in terms of brightness and light quality needs to be continuously improved. At present, more than 95% of the mainstream blue-green GaN-based LED epitaxial wafer uses a sapphire substrate as a substrate material, and the sapphire substrate is the most dominant substrate material in the mainstream LED market in the future due to the characteristics of high hardness, high light transmittance, mature process and the like. The sapphire substrate adopted at present is basically subjected to patterning (PATTERNED SAPPHIRE Substrates, PSS) processing and then is used for LED epitaxial growth. Because the gallium nitride epitaxial layer is grown on the PSS substrate, the epitaxial defect can be reduced, and the crystal quality of the epitaxial layer is improved so as to improve the electrical characteristics of the LED; in addition, the refractive index of the sapphire is 1.8, the refractive index of the gallium nitride is 2.5, and due to the difference of the refractive indexes, when light enters the sapphire patterned substrate from the gallium nitride epitaxial layer, total reflection is formed, so that the light yield of the GaN-based light emitting diode is improved. The parameters of the LED device made of the epitaxial material based on the PSS substrate show that the optical power of the chip with the same size under the current density of 20A/cm < 2 > is increased by about 30% compared with the optical power of the device made of the sapphire flat substrate, so that the PSS substrate is an effective method for improving the light emitting efficiency of the gallium nitride-based light emitting diode.

In the prior art, the PSS substrate is generally a pyramid-shaped three-dimensional pattern, as shown in fig. 1, the PSS substrate with the pyramid-shaped three-dimensional pattern mainly reflects the light emitted by the LED by means of the conical surface of the pyramid, and more light emitted by the LED is required to be reflected, so that the pyramid-shaped three-dimensional pattern is required to be made as dense as possible on the substrate, but the sapphire substrate (Al ₂O₃) is harder, etching is difficult, and etching depth and accuracy are difficult to control when the patterns are densely distributed.

Disclosure of utility model

The utility model aims to: aiming at the problems in the prior art, the utility model provides a patterned composite substrate and an epitaxial structure thereof, wherein the whole surface of a convex structure in the substrate is provided with a nanoscale microstructure, and the nanoscale microstructure is equivalent to increasing the density of the convex structure, increasing the reflecting surface area and improving the light emitting efficiency of an LED device; the patterning duty ratio of the C surface of the substrate is increased, so that the lateral epitaxial effect is improved, and the internal quantum efficiency of the LED device is improved; the upper part of the nano microstructure is designed into a silicon dioxide material, so that the reflectivity of the substrate can be further improved, and the light emitting efficiency of the substrate can be improved.

The technical scheme is as follows: the utility model provides a patterned substrate with a micro-nano structure, which comprises a substrate body, wherein the surface of the substrate body is provided with convex structures which are periodically arranged in a micron order, isolation grooves are arranged between adjacent convex structures, and the whole surface of each convex structure is distributed with a nano-scale microstructure; the nanoscale microstructure is composed of an upper cylinder microstructure and a lower cylinder microstructure, the upper cylinder microstructure is made of silicon dioxide, and the lower cylinder microstructure and the protruding structure are of an integrated structure and are the same in material.

Preferably, the grain diameter range of the nanoscale microstructure is 50-500 nm, the height range is 5-900 nm, and the interval range is 0-100 nm.

Preferably, the protruding structure is a cone, pyramid or missile structure.

Preferably, the period P of the bump structure ranges from 1000 nm to 5000 nm.

Preferably, the bottom diameter of the protruding structure is 800 nm-4900 nm, and the height is 500-3000 nm.

The utility model also provides an LED epitaxial structure with the micro-nano structure, which comprises the patterned substrate.

Further, the LED epitaxial structure with the micro-nano structure further comprises an N-type layer, a light-emitting layer and a P-type layer which are sequentially arranged on the patterned substrate.

The beneficial effects are that: in the patterned substrate with the micro-nano structure, the whole surface of the convex structure is provided with the nano-scale microstructure, and the nano-scale microstructure is equivalent to increasing the density of the convex structure, increasing the reflecting surface area and improving the light emitting efficiency of the substrate; increasing the patterning duty ratio of the C surface of the substrate is beneficial to improving the lateral epitaxial effect (when the substrate is not provided with a convex structure, the substrate is a plane, the plane is the C surface, the C surface is patterned on the C surface, the area of the C surface is reduced after the C surface is patterned, the crystal quality of the substrate is improved, the lateral epitaxial effect can be improved), and the internal quantum efficiency of the LED device is improved.

In addition, the nanoscale microstructure in the application is composed of an upper cylinder microstructure made of silicon dioxide and a lower cylinder microstructure made of the same material as that of a substrate body, wherein the substrate body is made of sapphire, and the silicon dioxide material has a lower refractive index than that of sapphire, so that the reflecting effect of light is more beneficial, and the reflectivity of the substrate can be further improved and the light emitting efficiency of the substrate can be improved by designing the upper microstructure of the nanoscale microstructure to be made of the silicon dioxide material.

Drawings

FIG. 1 is a side cross-sectional view of a prior art sapphire substrate having pyramid-shaped relief patterns;

Fig. 2 is a schematic structural diagram of a patterned substrate with a micro-nano structure in embodiment 1;

FIG. 3 is an enlarged schematic view of a portion of the structure of FIG. 2;

FIG. 4 is a scanning electron microscope picture of a patterned substrate having a micro-nano structure, wherein the top is a picture having a plurality of bump structures, and the bottom is an enlarged picture of one of the bump structures;

fig. 5 is a schematic diagram of an LED epitaxial structure including a patterned substrate with micro-nano structures.

Detailed Description

The present utility model will be described in detail with reference to the accompanying drawings.

The utility model provides a patterned substrate with a micro-nano structure, which is shown in fig. 2 and 3, and comprises a sapphire substrate body 1, wherein the surface of the sapphire substrate body is provided with conical structure convex structures 101 which are periodically distributed in a micron order, the convex structures 101 are integrally structured with the substrate body 1 and made of the same material, and isolation grooves 103 are formed between adjacent convex structures 101. The period P of the bump structure 101 is 2000nm, the bottom diameter d is 2000nm, and the height h is 1500 nm. The entire surface of the protruding structure 101 is distributed with nano-scale microstructures 102, and the nano-scale microstructures 102 are composed of an upper cylinder microstructure 1021 and a lower cylinder microstructure 1022, wherein the upper cylinder microstructure 1021 is made of silicon dioxide, and the lower cylinder microstructure 1022 and the protruding structure are integrated and made of the same material. The nanoscale microstructures 102 have a particle size range of 50-500 nm, a height range of 5-900 nm, and a pitch range of 0-100 nm. Fig. 4 is a scanning electron microscope image of the patterned substrate prepared by the method. The nano-scale microstructures 102 are equivalent to increasing the density of the raised structures 101, increasing the reflective surface area of the substrate, and improving the light extraction efficiency of the LED device. The upper microstructure 1021 is designed to be made of silicon dioxide material, so that the reflectivity of the substrate can be further improved, and the light emitting efficiency of the substrate can be improved.

Fig. 5 shows an LED epitaxial structure, which includes the patterned substrate with the nanoscale microstructure 102, and further includes an N-type layer 2, a light-emitting layer 3, and a P-type layer 4 sequentially disposed on the patterned substrate. The LED epitaxial structure with the patterned substrate improves the lateral epitaxial effect due to the patterning of the C surface of the substrate, and is beneficial to improving the internal quantum efficiency of an LED device.

The foregoing embodiments are merely illustrative of the technical concept and features of the present utility model, and are intended to enable those skilled in the art to understand the present utility model and to implement the same, not to limit the scope of the present utility model. All equivalent changes or modifications made according to the spirit of the present utility model should be included in the scope of the present utility model.

Claims

1. The patterned substrate with the micro-nano structure is characterized by comprising a substrate body (1) with a surface provided with micro-scale periodically arranged convex structures (101), wherein isolation grooves (103) are arranged between adjacent convex structures (101), and the whole surface of each convex structure (101) is distributed with nano-scale microstructures (102); the nanoscale microstructure (102) is composed of an upper cylinder microstructure (1021) and a lower cylinder microstructure (1022), the upper cylinder microstructure (1021) is made of silicon dioxide, and the lower cylinder microstructure (1022) and the protruding structure (101) are of an integrated structure and are the same in material.

2. The patterned substrate with micro-nano structure according to claim 1, wherein the nano-scale microstructure (102) has a particle size ranging from 50 to 500 nm, a height ranging from 5 to 900 nm, and a pitch ranging from 0 to 100 nm.

3. A patterned substrate with micro-nano structure according to claim 1, wherein the raised structures (101) are cone, pyramid or missile like structures.

4. The patterned substrate with micro-nano structure according to claim 1, wherein the period P of the bump structure (101) ranges from 1000 nm to 5000 nm.

5. The patterned substrate with micro-nano structure according to claim 1, wherein the bottom diameter d of the protruding structure (101) is 800 nm-4900 nm and the height h is 500-3000 nm.

6. An LED epitaxial structure with a patterned substrate of micro-nano structure, characterized in that it comprises a patterned substrate according to any of claims 1 to 5.

7. The LED epitaxial structure of claim 6, further comprising an N-type layer (2), a light emitting layer (3) and a P-type layer (4) disposed in sequence on the patterned substrate.