CN114038965B - Epitaxial substrate and manufacturing method thereof - Google Patents

Abstract

The present application relates to an epitaxial substrate and a manufacturing method thereof. The epitaxial substrate includes a substrate, a defect barrier layer and a nano-pattern layer. The defect barrier layer is disposed on one side of the substrate. The nano-pattern layer is disposed on a side of the defect barrier layer away from the substrate. The nano-pattern layer is composed of at least one layer. It is composed of nanoscale particles, and the nanoscale particles make the side of the nanopattern layer away from the substrate have a concave and convex surface. The above-mentioned defect blocking layer and the above-mentioned nano-pattern layer can block the threading dislocations extending from the epitaxial substrate to the film, thereby increasing the carrier concentration, improving the radiation recombination probability and internal quantum efficiency, improving the luminous efficiency of the device, and with nanometer The uneven surface of the pattern layer is the growth surface, which allows the growing epitaxial film to bend and merge dislocations through lateral growth, which promotes the longitudinal growth of the epitaxial film to become transverse growth and other non-vertical growth, thereby reducing the dislocations of the epitaxial film. density, improving the crystal quality of the epitaxial film.

Description

Epitaxial substrate and manufacturing method thereof

Technical field

The present application relates to the technical field of epitaxial thin films, and in particular to an epitaxial substrate and a manufacturing method thereof.

Background technique

Micro Light Emitting Diode (Micro-LED), as a new generation of display technology, is superior to Liquid Crystal Display (LCD) and LCD in terms of contrast, response time, energy consumption, viewing angle and resolution. Organic Light Emitting Diode (OLED) has attracted much attention.

Currently, Micro-LED is also facing many challenges, among which obtaining high-quality epitaxial films is one of them. Because the chip size of Micro-LED is small, usually tens of microns or even several microns, and the size of the traditional pattern substrate is in the micron range, it can no longer meet the demand. High-quality and high-luminous efficiency epitaxial wafers are made on the substrate. has become one of the important topics.

The main epitaxy technology now is heteroepitaxial, and heteroepitaxial films have a high dislocation density. The threading dislocation between the epitaxial film and the substrate is an effective non-radiative coincidence center. In the dislocation-dense area, carriers are greatly reduced due to the non-radiative recombination center, thereby reducing the radiative recombination efficiency and reducing the performance of Micro-LED. Internal quantum efficiency affects its luminous efficiency.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the purpose of this application is to provide an epitaxial substrate and a manufacturing method thereof, aiming to solve the technical problem in the prior art that the epitaxial film has threading dislocations, resulting in reduced luminous efficiency of the device.

An epitaxial substrate, which includes:

substrate;

a defect barrier layer disposed on one side of the substrate; and

The nano-pattern layer is arranged on the side of the defect barrier layer away from the substrate. The nano-pattern layer is composed of at least one layer of nano-sized particles. The nano-sized particles make the side of the nano-pattern layer far away from the substrate have a concave and convex surface.

When the epitaxial substrate provided in this application is used for the growth process of the epitaxial film, the defect blocking layer and the nano-pattern layer in the epitaxial substrate can block the threading dislocations extending from the epitaxial substrate to the film, thereby effectively increasing the carrier concentration. The radiation recombination probability and internal quantum efficiency are improved, thereby improving the luminous efficiency of the device. At the same time, because the nano-pattern layer is composed of at least one layer of nano-scale particles, the nano-scale particles make the side of the nano-pattern layer away from the substrate have a concave and convex surface. Therefore, using the uneven surface as the growth surface, the growing epitaxial film can bend and merge dislocations through lateral growth, thereby promoting the longitudinal growth of the epitaxial film to non-vertical growth such as transverse growth, thereby reducing the dislocations of the epitaxial film. density, improves the crystal quality of the epitaxial film, and effectively avoids the reduction in device luminous efficiency caused by threading dislocations in the epitaxial film in the prior art.

Optionally, the above-mentioned nanoscale particles have a polyhedral structure. After the polyhedral-structured nano-sized particles form the nano-pattern layer, the surface of the nano-pattern layer away from the substrate can have planes parallel to multiple directions, thereby enabling the epitaxial film to grow non-vertically, thereby reducing the cost of the epitaxial film. dislocation density.

Optionally, the above-mentioned nanoscale particles are silicon crystal particles. Silicon crystal particles usually have a tetrahedral structure, and the process is simple and easy to form through processes such as magnetron sputtering. The nanopattern layer formed by using silicon crystal particles can effectively promote the longitudinal growth of the epitaxial film into lateral growth, thus reducing the cost of the epitaxial film. dislocation density.

Optionally, the particle size of the above-mentioned nanoparticles is 10 to 100 nm. Nanoscale particles that meet the above particle size range can make the side of the nanopattern layer away from the substrate have surfaces with multiple different directions, thereby allowing the growing epitaxial film to bend and merge dislocations through lateral growth, further reducing the Dislocation density of epitaxial films.

Optionally, the above defect blocking layer is a SiN _x layer. The SiN _x layer has high density and can effectively prevent penetrating defects _in the epitaxial substrate from extending into the epitaxial layer. The _SiN The defect barrier layer can effectively reduce the dislocation density of the epitaxial film, thereby improving the crystal quality of the epitaxial film.

Optionally, the above-mentioned substrate is selected from any one of sapphire substrate, silicon substrate and silicon carbide substrate. The above-mentioned types of substrates have relatively high hardness, thereby avoiding the impact of the defect blocking layer and/or the nanopattern layer formed by the magnetron sputtering process on the reliability of the substrate.

Based on the same inventive concept, this application also provides a method for manufacturing the above-mentioned epitaxial substrate, including the following steps:

Depositing a defect blocking layer on the substrate;

At least one layer of nanoscale particles is deposited on the defect blocking layer to form a nanopatterned layer with a bumpy surface.

When the epitaxial substrate obtained by the above manufacturing method of the present application is used for the growth process of the epitaxial film, the defect barrier layer and the nano-pattern layer can block the threading dislocations extending from the epitaxial substrate to the film, thereby effectively increasing the carrier concentration and improving the Radiation recombination probability and internal quantum efficiency, thereby improving the luminous efficiency of the device. At the same time, because the nano-pattern layer is composed of at least one layer of nano-scale particles, the nano-scale particles make the side of the nano-pattern layer away from the substrate have a concave and convex surface. This uneven surface is a growth surface, which allows the growing epitaxial film to bend and merge dislocations through lateral growth, promoting the longitudinal growth of the epitaxial film to non-vertical growth such as transverse growth, thereby reducing the dislocation density of the epitaxial film. The crystal quality of the epitaxial film is improved, and the reduction in the luminous efficiency of the device caused by threading dislocations in the epitaxial film in the prior art is effectively avoided.

Optionally, in the step of forming the defect blocking layer, a first magnetron sputtering process is used to bombard the silicon target under nitrogen-rich conditions to form a SiN _x layer on the substrate to obtain the defect blocking layer. In the above-mentioned first magnetron sputtering process, a dense SiN _x layer is formed by bombarding the silicon target under nitrogen-rich conditions to prevent substrate penetration defects from extending to the epitaxial layer.

Optionally, the substrate is placed into the reaction chamber and nitrogen gas is introduced, and the working pressure in the reaction chamber is adjusted to 0.5-5 Pa to form nitrogen-rich conditions. The nitrogen-rich conditions formed under the above working pressure can form a dense SiN _x layer through the first magnetron sputtering process, thereby effectively blocking the substrate penetration defects from extending to the epitaxial layer.

Optionally, in the step of forming the above-mentioned nanopattern layer, a second magnetron sputtering process is used to bombard the silicon target under silicon-rich conditions to form at least one layer of silicon crystal particles on the SiN _x layer. In the above second magnetron sputtering process, particles in the form of Si-Si are formed by bombarding the silicon target under silicon-rich conditions. Since the Si-Si particles are nanoscale patterns with a tetrahedral structure, the Si-Si particles are The formed nanoscale pattern layer has a concave and convex surface on the side away from the substrate, which allows the growing epitaxial film to bend and merge dislocations through lateral growth, thereby promoting non-vertical growth such as longitudinal growth of the epitaxial film into transverse growth.

Optionally, make the nitrogen flow rate in the second magnetron sputtering process smaller than the nitrogen flow rate in the first magnetron sputtering process to form silicon-rich conditions; or make the work in the reaction chamber in the second magnetron sputtering process The pressure is greater than the working pressure in the reaction chamber in the first magnetron sputtering process to form silicon-rich conditions; or the operating temperature in the second magnetron sputtering process is greater than the operating temperature in the first magnetron sputtering process, so as to Form a silicon-rich condition; or make the sputtering power in the second magnetron sputtering process greater than the sputtering power in the first magnetron sputtering process to form a silicon-rich condition. Using any of the above optional methods, silicon-rich conditions can be obtained, thereby forming particles in the form of Si-Si through the second magnetron sputtering process.

Description of the drawings

Figure 1 is a schematic partial cross-sectional structural diagram of an epitaxial substrate provided in an embodiment of the present application;

FIG. 2 is a schematic flowchart of a method for manufacturing an epitaxial substrate according to an embodiment of the present application.

Explanation of reference symbols:

10-Substrate; 20-Defect barrier layer; 30-Nano pattern layer; 310-Nanometer particles.

Detailed ways

In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the accompanying drawings. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and comprehensive understanding of the disclosure of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing specific embodiments only and is not intended to limit the application.

As described in the background section, the main epitaxy technology now is heteroepitaxial, and heteroepitaxial films have a high dislocation density. The threading dislocation between the epitaxial film and the substrate is an effective non-radiative coincidence center. In the dislocation-dense area, carriers are greatly reduced due to the non-radiative recombination center, thereby reducing the radiative recombination efficiency and reducing the performance of Micro-LED. Internal quantum efficiency affects its luminous efficiency.

Based on this, the present application hopes to provide a solution that can solve the above technical problems, the details of which will be elaborated in subsequent embodiments.

The inventor of this application conducted research on the above problems and proposed an epitaxial substrate, as shown in Figure 1, including:

substrate 10;

Defect barrier layer 20 is provided on one side of substrate 10; and

The nano-pattern layer 30 is disposed on the side of the defect blocking layer 20 away from the substrate 10. The nano-pattern layer 30 is composed of at least one layer of nano-scale particles 310. The nano-scale particles 310 make the side of the nano-pattern layer 30 away from the substrate 10 have Concave and convex surface.

When the epitaxial substrate provided in this application is used for the growth process of the epitaxial film, the defect blocking layer 20 and the nano-pattern layer 30 in the epitaxial substrate can block the threading dislocations extending from the epitaxial substrate to the film, thereby effectively increasing carriers. The concentration increases the radiation recombination probability and internal quantum efficiency, thereby improving the luminous efficiency of the device. At the same time, because the nano-pattern layer 30 is composed of at least one layer of nano-scale particles 310, the nano-scale particles 310 keep the nano-pattern layer 30 away from the substrate 10 One side has a concave and convex surface, so that the concave and convex surface is used as the growth surface, which enables the growing epitaxial film to bend and merge dislocations through lateral growth, thereby promoting the longitudinal growth of the epitaxial film to change to non-vertical growth such as transverse growth, and then It can reduce the dislocation density of the epitaxial film, improve the crystal quality of the epitaxial film, and effectively avoid the reduction in the luminous efficiency of the device caused by the threading dislocations in the epitaxial film in the prior art.

In some embodiments, the above-mentioned substrate 10 may be a sapphire substrate 10, a silicon substrate 10 or a silicon carbide substrate 10. The above-mentioned type of substrate 10 has relatively high hardness, thereby avoiding the impact of the defect barrier layer 20 and/or the nanopattern layer 30 formed by the magnetron sputtering process on the reliability of the substrate 10 .

In some embodiments, the above-mentioned nanoscale particles 310 have a polyhedral structure. After the polyhedral-structured nano-sized particles 310 form the nano-pattern layer 30, the surface of the nano-pattern layer 30 away from the substrate 10 can have planes parallel to multiple directions, thereby enabling the epitaxial film to grow non-vertically, and further The dislocation density of the epitaxial film is reduced.

Illustratively, the above-mentioned nanoscale particles 310 are silicon crystal particles. Silicon crystal particles usually have a tetrahedral structure, and the process is simple and easy to form through processes such as magnetron sputtering. The nanopattern layer 30 formed by using silicon crystal particles can effectively promote the longitudinal growth of the epitaxial film into lateral growth, thus reducing the cost of epitaxial growth. Dislocation density of the film.

In some embodiments, the particle size of the nanoparticles 310 is 10 to 100 nm. Nanoscale particles 310 that meet the above particle size range can make the side of the nanopattern layer 30 away from the substrate 10 have surfaces with multiple different directions, thereby bending and merging dislocations through lateral growth of the growing epitaxial film, The dislocation density of the epitaxial film is further reduced.

For example, the above-mentioned defect blocking layer 20 is a SiN _x layer. The SiN _x layer has high density and can effectively prevent penetrating defects _in the epitaxial substrate from extending into the epitaxial layer. The _SiN The defect blocking layer 20 can effectively reduce the dislocation density of the epitaxial film, thereby improving the crystal quality of the epitaxial film.

The above-mentioned epitaxial substrate of the present application can be used in the manufacturing process of light-emitting devices such as micro-light-emitting diodes (Micro-LED), liquid crystal displays (LCD), and organic light-emitting semiconductors (OLED). This application does not limit its application scenarios.

Based on the same inventive concept, this application also provides a method for manufacturing the above-mentioned epitaxial substrate, as shown in Figure 2, including the following steps:

Deposit and form a defect barrier layer 20 on the substrate 10;

At least one layer of nanoscale particles 310 is deposited on the defect blocking layer 20 to form a nanopatterned layer 30 having a concave and convex surface.

When the epitaxial substrate obtained by the above manufacturing method of the present application is used for the growth process of the epitaxial film, the defect blocking layer 20 and the nano-pattern layer 30 can block the threading dislocations extending from the epitaxial substrate to the film, thereby effectively increasing the carrier concentration. The radiation recombination probability and internal quantum efficiency are improved, thereby improving the luminous efficiency of the device. At the same time, because the nano-pattern layer 30 is composed of at least one layer of nano-scale particles 310, the nano-scale particles 310 keep the nano-pattern layer 30 away from the substrate 10. The side has a concave and convex surface, so that the concave and convex surface is used as the growth surface, which enables the growing epitaxial film to bend and merge dislocations through lateral growth, promoting the longitudinal growth of the epitaxial film to become transverse growth and other non-vertical growth, thereby reducing the The dislocation density of the epitaxial film improves the crystal quality of the epitaxial film and effectively avoids the reduction in device luminous efficiency caused by threading dislocations in the epitaxial film in the prior art.

In some embodiments, the above-mentioned substrate 10 may be a sapphire substrate 10, a silicon substrate 10 or a silicon carbide substrate 10.

In some embodiments, a first magnetron sputtering process is used to deposit SiN _x on the substrate 10 to obtain the defect blocking layer 20 . In the first magnetron sputtering process, a dense SiN _x layer can be formed by bombarding the silicon target under nitrogen-rich conditions to prevent substrate penetration defects from extending to the epitaxial layer.

In order to use the first magnetron sputtering process to form the above-mentioned defect blocking layer 20 under nitrogen-rich conditions, the above-mentioned first magnetron sputtering process includes the following steps:

Step S101: Place the substrate 10 in the PVD reaction chamber. The distance between the substrate 10 and the silicon target can be 30 to 100 mm;

Step S102: Evacuate the PVD reaction chamber to a vacuum degree of 1×10 ^-4 to 1×10 ^-8 Torr, and heat the substrate 10 to a pretreatment temperature of 300 to 700°C;

Step S103: Bake the substrate 10 for 2 to 15 minutes under the conditions of step S102;

Step S104, pass in N ₂ , adjust the temperature of the substrate 10 to a reaction temperature of 100 to 500°C, and adjust the pressure in the chamber to a nitriding pressure of 0.5 to 5 Pa;

Step S105: Form dense SiNx with a sputtering power of 50-1000W under the nitrogen-rich condition in step S104, and the thickness may be 10-100 nm.

In some embodiments, a second magnetron sputtering process is used to deposit silicon crystal particles on the substrate 10 to obtain the nanopatterned layer 30 . In the above-mentioned second magnetron sputtering process, particles in the form of Si-Si can be formed by bombarding the silicon target under silicon-rich conditions. The Si-Si particles can be regarded as nanoscale patterns with a tetrahedral structure. From the Si-Si The side of the nanoscale pattern layer formed by the particles away from the substrate 10 has a concave and convex surface, which enables the growing epitaxial film to bend and merge dislocations through lateral growth, thereby promoting the longitudinal growth of the epitaxial film to become transverse growth and other non-vertical growth. grow.

In order to use the second magnetron sputtering process to form the above-mentioned nanopattern layer 30 under silicon-rich conditions, exemplary, the above-mentioned second magnetron sputtering process includes the following steps:

Step S201, close the silicon target baffle, adjust the silicon-rich condition of the reaction chamber to a temperature of 100-500°C and a pressure of 0.5-5Pa;

Step S202, when the reaction chamber reaches silicon-rich conditions, open the silicon target baffle and bake for a small amount of time less than 1 minute;

Step S203, use sputtering power under silicon-rich conditions to form Si-Si particles on the surface of SiNx with a particle size of 10 to 100 nm. The Si-Si particles can be regarded as nanoscale patterns, and at least one layer of Si-Si particles constitutes a nanometer-scale pattern. Graphics layer 30.

In order to achieve silicon-rich conditions in the reaction chamber, in the above step S201, the flow rate of _N2 in the second magnetron sputtering process can be made smaller than the flow rate of _N2 in the first magnetron sputtering process, or the second magnetron sputtering process can be made The working pressure in the reaction chamber in the controlled sputtering process is greater than the working pressure in the reaction chamber in the first magnetron sputtering process, and the working temperature in the second magnetron sputtering process can also be made higher than that in the first magnetron sputtering process. The operating temperature can also make the sputtering power in the second magnetron sputtering process greater than the sputtering power in the first magnetron sputtering process. Therefore, this application does not limit the method of achieving silicon-rich conditions in the embodiment.

It should be understood that the application of the present application is not limited to the above examples. For those of ordinary skill in the art, improvements or changes can be made based on the above descriptions. All these improvements and changes should fall within the protection scope of the appended claims of the present application.

Claims (6)

1. A method for manufacturing an epitaxial substrate, characterized in that it includes the following steps: Depositing a defect blocking layer on the substrate; depositing at least one layer of continuous nanoscale particles with a polyhedral structure on the defect barrier layer to form a nanopattern layer with a concave and convex surface, Wherein, a second magnetron sputtering process is used to deposit silicon crystal particles on the substrate to obtain the nano-pattern layer. In the second magnetron sputtering process, the silicon target material is bombarded under silicon-rich conditions. Particles in the form of Si-Si. 2. The epitaxial substrate according to claim 1, wherein the particle size of the nano-sized particles is 10 to 100 nm. 3. The epitaxial substrate according to claim 1 or 2, wherein the defect blocking layer is a SiN _x layer. 4. The manufacturing method of claim 1, wherein in the step of forming the defect barrier layer, a first magnetron sputtering process is used to bombard the silicon target material under nitrogen-rich conditions to form the defect barrier layer. A SiN _x layer is formed on the substrate. 5. The manufacturing method according to claim 4, characterized in that, the substrate is placed into a reaction chamber and nitrogen gas is introduced, and the working pressure in the reaction chamber is adjusted to 0.5~5Pa to form the rich Nitrogen conditions. 6. The manufacturing method according to claim 4, characterized in that: Make the nitrogen flow rate in the second magnetron sputtering process less than the nitrogen flow rate in the first magnetron sputtering process to form the silicon-rich condition; or Make the working pressure in the reaction chamber in the second magnetron sputtering process greater than the working pressure in the reaction chamber in the first magnetron sputtering process to form the silicon-rich condition; or Making the operating temperature in the second magnetron sputtering process greater than the operating temperature in the first magnetron sputtering process to form the silicon-rich condition; or The sputtering power in the second magnetron sputtering process is made greater than the sputtering power in the first magnetron sputtering process to form the silicon-rich condition.