A two-dimensional layered silicon carbide semiconductor material and a method for preparing the same

Abstract

The application discloses a two-dimensional layered silicon carbide semiconductor material and a preparation method thereof, and belongs to the technical field of semiconductor materials. The preparation method comprises the following steps: adding a silicon source and metal carbide into a container according to a proportion, adding an organic solvent to perform ultrasonic reaction, and sequentially performing centrifugation, acid washing, deionized water washing, ethanol washing and drying on a reaction product to obtain the two-dimensional layered silicon carbide semiconductor material; the silicon source is selected from tetraethyl orthosilicate, silicic acid, orthosilicic acid, methyl silicic acid, disilicic acid, sodium silicate and ethyl silane; the metal carbide is selected from alkali metal acetylide, alkaline earth metal acetylide or transition metal carbide; and the organic solvent is selected from anhydrous ethanol, isopropyl alcohol and ethylene glycol. The obtained silicon carbide presents a two-dimensional layered structure and a 6H-SiC crystal form, the method is simple, the cost is low, the use of excessively high temperature is avoided, the use of dangerous raw materials and the generation of by-products are also avoided.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor materials technology, specifically relating to a two-dimensional layered silicon carbide semiconductor material and its preparation method. Background Technology

[0002] Silicon (Si), the first-generation semiconductor material, is widely used in the integrated circuit industry, and silicon chips shine brightly in every corner of human society. However, with the continuous development of semiconductor technology, the performance of Si-based semiconductor devices is gradually approaching the limits of their material properties. They often fail when facing high-temperature, high-power, and high-frequency operating scenarios, greatly limiting the development of the semiconductor integrated circuit and electronic device industries. Therefore, researchers have gradually turned their attention to third-generation wide-bandgap semiconductor materials with superior material properties, such as silicon carbide (SiC) and gallium nitride (GaN). Due to the superior physical properties of SiC and the many similarities between the manufacturing processes of SiC-based semiconductor devices and Si devices, it is considered the most promising semiconductor material after Si.

[0003] Silicon carbide (SiC) possesses excellent physical properties such as ultra-wide bandgap, high electrical conductivity, high thermal conductivity, high carrier saturation mobility, high breakdown field strength, low coefficient of thermal expansion, and radiation resistance. It can withstand extreme operating environments such as high voltage, high frequency, high temperature, strong radiation, and high power, and can significantly improve the power density and conversion efficiency of devices. This drives the development of power electronic devices towards high efficiency, low energy consumption, and miniaturization and lightweight design. As a power device material, it has significant advantages and broad prospects in aerospace, 5G communications, new energy vehicles, and smart grids. In addition, SiC also possesses high elastic modulus, high hardness, high strength, low density, high mechanical stability, photoluminescence, chemical inertness, high biocompatibility, and good microwave absorption. Therefore, it has become a high-performance candidate material for many fields, including flexible electronic devices, catalysis, biomaterials, and sensors. However, the high technical threshold, low yield, and high cost of SiC substrate fabrication restrict its development, resulting in overall industry capacity falling far short of market demand. Furthermore, there is currently a significant gap between domestic and international leading companies in terms of both technology and scale.

[0004] Developing green, environmentally friendly, low-cost, and easy-to-operate SiC material synthesis technologies is a crucial step in promoting its application research. Currently, widely used SiC synthesis methods mainly include carbothermal reduction, gas-phase synthesis, template synthesis, and sol-gel synthesis. Carbothermal reduction uses quartz sand as raw material and coke or pitch as a reducing agent, heating it in an electric furnace to above 1900℃. The product is hexagonal blocky SiC, which requires multiple steps including crushing, grinding, acid leaching, water washing, drying, and grading to finally obtain α-SiC powder. This method is relatively complex, and the product has a coarse particle size. Gas-phase synthesis is divided into plasma synthesis, laser synthesis, and electric furnace synthesis, depending on the heating method. Except for the laser synthesis method which uses SiH4 as raw material, gas-phase synthesis generally uses low-boiling-point chlorides containing Si or Si and C at temperatures above 1500℃ to decompose or synthesize SiC powder, producing cubic β-SiC. Roughly estimated, the current cost of powder preparation using the vapor phase method is more than 10 times higher than that of powder preparation using the carbothermal reduction method. Therefore, it is necessary to develop a more suitable method for preparing SiC semiconductor materials. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, the main objective of this invention is to provide a method for preparing two-dimensional layered silicon carbide semiconductor materials.

[0006] Another object of the present invention is to provide a two-dimensional layered silicon carbide semiconductor material.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for preparing a two-dimensional layered silicon carbide semiconductor material, comprising the following steps:

[0009] Step 1: Add the silicon source and metal carbide to a container in a certain proportion, and add an organic solvent to carry out an ultrasonic reaction;

[0010] Step 2: The product after ultrasonic reaction is post-processed, including centrifugation, acid washing, deionized water washing, ethanol washing and drying, to obtain two-dimensional layered silicon carbide semiconductor material.

[0011] The silicon source is selected from one or more combinations of tetraethyl orthosilicate, silicic acid, orthosilicic acid, methylsilicic acid, disilicate, sodium silicate, and ethylsilane.

[0012] The metal carbide is selected from one or more combinations of alkali metal acetylides, alkaline earth metal acetylides, or transition metal carbides.

[0013] The organic solvent is selected from one or more combinations of anhydrous ethanol, isopropanol, and ethylene glycol.

[0014] Preferably, the alkali metal acetylide is selected from one or more combinations of lithium carbide, sodium carbide or potassium carbide, and the alkaline earth metal acetylide is selected from calcium carbide and / or magnesium carbide.

[0015] Preferably, the silicon source is tetraethyl orthosilicate.

[0016] Preferably, the silicon source is tetraethyl orthosilicate, the metal carbide is calcium carbide, the reaction is carried out in anhydrous ethanol by ultrasonication, and the molar ratio of tetraethyl orthosilicate to calcium carbide is 1 to 8:8.

[0017] Preferably, the tetraethyl orthosilicate and calcium carbide are ultrasonically reacted in anhydrous ethanol at a molar ratio of 2 to 8:1, while maintaining an excess of tetraethyl orthosilicate.

[0018] Preferably, the tetraethyl orthosilicate and calcium carbide are ultrasonically reacted in anhydrous ethanol at a molar ratio of 1:2 to 8, while maintaining an excess of calcium carbide.

[0019] Preferably, the ultrasonic frequency used is 35–53 kHz.

[0020] Preferably, the ultrasonic reaction time is 1 to 36 hours, more preferably 6 to 24 hours.

[0021] Preferably, the water temperature is kept below 50°C, preferably 15-35°C, during the ultrasonic reaction process using a water circulation method.

[0022] Preferably, the pickling is performed using a dilute nitric acid solution with a concentration of 0.1–2.5 mol / L.

[0023] Preferably, the drying temperature is 60–80°C and the drying time is 12–24 hours.

[0024] The present invention also provides a two-dimensional layered silicon carbide semiconductor material, which is prepared by the preparation method of the two-dimensional layered silicon carbide semiconductor material, and has a 6H-SiC crystal form and exhibits a two-dimensional layered structure.

[0025] Compared with existing technologies, the advantages of this invention are as follows: This invention proposes a method for preparing two-dimensional layered silicon carbide semiconductor materials, for example, using tetraethyl orthosilicate and metal acetylation as raw materials, and preparing them by ultrasonication. The metal acetylation is two-dimensional, and a silicon source is introduced to form two-dimensional silicon carbide, which can be used in integrated circuits and new energy fields. Furthermore, the ultrasonic method used is simple and low-cost, while avoiding the use of excessively high temperatures, hazardous raw materials, and byproducts. Attached Figure Description

[0026] Figure 1 The image shows the XRD pattern of the two-dimensional layered silicon carbide semiconductor material prepared in Example 1.

[0027] Figure 2 The image shows the XRD pattern of the two-dimensional layered silicon carbide semiconductor material prepared in Example 2.

[0028] Figure 3 XRD pattern of silicon carbide semiconductor obtained in Example 3;

[0029] Figure 4 XRD pattern of silicon carbide semiconductor obtained in Example 4;

[0030] Figure 5 Transmission electron microscope image (1µm) of the two-dimensional layered silicon carbide semiconductor material prepared in Example 1;

[0031] Figure 6 Transmission electron microscope image (5nm) of the two-dimensional layered silicon carbide semiconductor material prepared in Example 1;

[0032] Figure 7 This is an atomic force microscope image of the two-dimensional layered silicon carbide semiconductor material prepared in Example 1. Detailed Implementation

[0033] To further clarify the purpose and technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, the scope of protection of the present invention is not limited to the following embodiments.

[0034] The following examples present a method for synthesizing two-dimensional layered silicon carbide semiconductor materials. The raw materials used are: metal acetylation (calcium carbide) and silicon source (tetraethyl orthosilicate), with a molar ratio of 1–8:8; the solvent (ethanol) does not react with either material. Equipment used is an ultrasonic cleaner (ultrasonic frequency 35–53 kHz, time 6–36 h, temperature 15–35 °C).

[0035] Example 1

[0036] This embodiment proposes a method for preparing a two-dimensional layered silicon carbide semiconductor material. The steps are as follows: tetraethyl orthosilicate and calcium carbide with a molar ratio of 2:1 are placed in a container, and anhydrous ethanol is added. The mixture is ultrasonicated at a working frequency of 40 kHz for 12 hours. Water circulation is used to ensure that the water temperature is maintained at 25°C. Then, the mixture is centrifuged, acid-washed with a 1 mol / L dilute nitric acid solution, washed with deionized water, washed with ethanol, and dried (drying temperature is 60°C, drying time is 12 hours) to obtain the two-dimensional layered silicon carbide semiconductor material.

[0037] Example 2

[0038] This embodiment proposes a method for preparing a two-dimensional layered silicon carbide semiconductor material, which is basically the same as in Embodiment 1, except that the molar ratio of tetraethyl orthosilicate to calcium carbide is 1:2.

[0039] Example 3

[0040] This embodiment proposes a method for preparing a two-dimensional layered silicon carbide semiconductor material, which is basically the same as that in Embodiment 1, except that the operating frequencies are 53kHz and 35kHz, respectively.

[0041] Example 4

[0042] This embodiment proposes a method for preparing a two-dimensional layered silicon carbide semiconductor material, which is basically the same as that in Embodiment 1, except that the ultrasonic time is 1h, 6h and 24h respectively.

[0043] Example 5

[0044] This embodiment proposes a method for preparing a two-dimensional layered silicon carbide semiconductor material, which is basically the same as in Embodiment 1, except that the solvent used is isopropanol.

[0045] Example 6

[0046] This embodiment proposes a method for preparing a two-dimensional layered silicon carbide semiconductor material, which is basically the same as in Embodiment 1, except that the metal carbide used is lithium carbide.

[0047] Figures 1-4 The XRD patterns of the two-dimensional layered silicon carbide semiconductor materials prepared in Examples 1 to 6 are shown respectively. It can be seen that the diffraction peaks at 33.8°, 35.5°, 37.6°, 41.0°, 44.9°, 59.7° and 71.4° correspond to (101), (006), (103), (104), (105), (108) and (116) respectively, which proves that the prepared SiC belongs to 6H-SiC. It can be seen that the excess of tetraethyl orthosilicate can increase the yield of silicon carbide to a certain extent. The excess of calcium carbide may have the presence of other impurity peaks that have not been completely washed away by nitric acid. At different operating frequencies, the yield and crystallinity of 35Hz and 53Hz are not as good as those of 40Hz.

[0048] Figure 5 The image shown is a transmission electron microscope image of the two-dimensional layered silicon carbide semiconductor material prepared in Example 1. It can be seen that the prepared silicon carbide exhibits a two-dimensional layered structure.

[0049] Figure 6 The image shown is a high-resolution transmission electron microscope image of the two-dimensional layered silicon carbide semiconductor material prepared in Example 1. The observed lattice spacing is 0.252 nm, corresponding to the (006) crystal plane of 6H-SiC. The clear lattice stripes further indicate that the sample has a high degree of crystallinity.

[0050] Figure 7The image shown is an atomic force microscope image of the two-dimensional layered silicon carbide semiconductor material prepared in Example 1. It can be seen that the thickness of the silicon carbide prepared by this method is 1.61 nm. Generally, the thickness of a single layer of two-dimensional silicon carbide is approximately the length of one carbon-silicon bond, about 0.3 nm. The thickness of multilayer two-dimensional silicon carbide increases with the number of layers, indicating that the silicon carbide prepared by this method has approximately 5 to 6 layers.

[0051] The results above show that two-dimensional layered silicon carbide semiconductor materials can be successfully prepared by ultrasonication using suitable silicon sources and metal carbides as raw materials. This is of great significance and practical value for the study of two-dimensional layered silicon carbide semiconductor materials and the promotion of their application.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for producing a two-dimensional layered silicon carbide semiconductor material, characterized by, The method comprises the following steps: Step 1: proportionally adding a silicon source and a metal carbide into a container, and adding an organic solvent to the container for ultrasonic reaction; Step 2: performing post-treatment on the product after ultrasonic reaction, including sequentially centrifuging, acid washing, deionized water washing, ethanol washing and drying, to obtain a two-dimensional layered silicon carbide semiconductor material; The silicon source is selected from one or more than two combinations of tetraethyl orthosilicate, silicic acid, orthosilicic acid, methylsilicic acid, disilicic acid, sodium silicate and ethylsilane; The metal carbide is selected from alkali metal acetylide and / or alkaline earth metal acetylide; The organic solvent is selected from one or more than two combinations of anhydrous ethanol, isopropanol and ethylene glycol.

2. The method of producing a two-dimensional layered silicon carbide semiconductor material according to claim 1, wherein The alkali metal acetylide is selected from one or more than two combinations of lithium carbide, sodium carbide or potassium carbide; The alkaline earth metal acetylide is selected from calcium carbide and / or magnesium carbide.

3. The method for preparing the two-dimensional layered silicon carbide semiconductor material according to claim 1, characterized in that, The silicon source is tetraethyl orthosilicate.

4. The method of claim 1, wherein the two-dimensional layered silicon carbide semiconductor material is prepared by a method comprising: providing a silicon carbide single crystal; and exfoliating the silicon carbide single crystal to form the two-dimensional layered silicon carbide semiconductor material. The silicon source is tetraethyl orthosilicate, the metal carbide is calcium carbide, and the ultrasonic reaction is performed in anhydrous ethanol.

5. The method of claim 4, wherein the two-dimensional layered silicon carbide semiconductor material is prepared by a method comprising: The tetraethyl orthosilicate and the calcium carbide are ultrasonically reacted in anhydrous ethanol at a molar ratio of 2-8:1, and the tetraethyl orthosilicate is kept in excess.

6. The method of claim 4, wherein the two-dimensional layered silicon carbide semiconductor material is prepared by a method comprising: The tetraethyl orthosilicate and the calcium carbide are ultrasonically reacted in anhydrous ethanol at a molar ratio of 1:2-8, and the calcium carbide is kept in excess.

7. The method of claim 1, wherein the two-dimensional layered silicon carbide semiconductor material is prepared by a method comprising: providing a silicon carbide single crystal; and exfoliating the silicon carbide single crystal to form the two-dimensional layered silicon carbide semiconductor material. The working frequency for the ultrasonic is 35-53 kHz.

8. The method of claim 1, wherein the two-dimensional layered silicon carbide semiconductor material is prepared by a method comprising: The time for the ultrasonic reaction is 1-36 h; And / or the water circulation method is adopted to keep the water temperature below 50℃ during the ultrasonic reaction.

9. The method of claim 1, wherein the two-dimensional layered silicon carbide semiconductor material is prepared by a method comprising: providing a silicon carbide single crystal; and exfoliating the silicon carbide single crystal to form the two-dimensional layered silicon carbide semiconductor material. The acid washing adopts a dilute nitric acid solution with a concentration of 0.1-2.5 mol / L; And / or the drying temperature is 60-80℃, and the drying time is 12-24 h.

10. A two-dimensional layered silicon carbide semiconductor material, characterized by, The two-dimensional layered silicon carbide semiconductor material prepared by the method of any one of claims 1-9 is in a 6H-SiC crystal form and presents a two-dimensional layered structure.

Images