阅读说明：本技术 一种在SiC衬底上直接生长MoS2薄膜的方法 (MoS directly growing on SiC substrate2Method for making thin film ) 是由 黄玲琴 陶化文 潘苏敏 于 2021-07-26 设计创作，主要内容包括：一种在SiC衬底上直接生长MoS-(2)薄膜的方法,包括：先将衬底进行清洗,然后将硫粉和三氧化钼粉作为硫源和钼源,其分别放在滑轨炉的低温区和高温区,将SiC衬底放在MoO-(3)粉的下游,并在滑轨炉中通一定流速的保护气,之后将滑轨炉的低温区和高温区以指定升温速度升至所需温度并且保温生长一段时间,生长完成之后自然降至室温。本发明的方法操作简单,可在SiC衬底上直接生长高质量的MoS-(2)薄膜,生长的MoS-(2)薄膜具有面积较大、尺寸较均匀以及生长速度快等优点。(MoS directly growing on SiC substrate 2 A method of making a film, comprising: firstly cleaning a substrate, then taking sulfur powder and molybdenum trioxide powder as a sulfur source and a molybdenum source, respectively placing the sulfur source and the molybdenum source in a low-temperature region and a high-temperature region of a slide rail furnace, and placing a SiC substrate in MoO 3 And introducing protective gas at a certain flow rate into the downstream of the powder in the slide rail furnace, then heating the low-temperature area and the high-temperature area of the slide rail furnace to the required temperature at a specified heating speed, preserving the temperature for growing for a period of time, and naturally cooling to room temperature after the growth is finished. The method of the invention has simple operation and can directly grow high-quality MoS on the SiC substrate 2 Thin film, grown MoS 2 The film has the advantages of large area, uniform size, high growth speed and the like.)

1. MoS directly growing on SiC substrate₂A method of forming a film, comprising the steps of:

s1: cleaning the SiC substrate;

s2: weighing sulfur S powder and MoO₃The powder is respectively arranged in a quartz boat, and the cleaned SiC substrate is put in a quartz boat filled with MoO₃In the quartz boat of the powder, MoO is filled in the quartz boat₃Placing the quartz boat containing the S powder in a low-temperature area of the tube furnace;

s3: vacuumizing the tube furnace;

s4: introducing Ar gas as protective gas, heating the high-temperature region to 650-700 ℃, heating the low-temperature region to 160-180 ℃, reacting at constant temperature for a period of time, and then naturally cooling.

2. The method according to claim 1, wherein the step S1 includes: the sample is respectively ultrasonically cleaned in acetone and isopropanol, then is soaked in a solution prepared from hydrogen peroxide and sulfuric acid, is soaked and washed for several times by deionized water, then the deionized water on the surface of the sample is thrown off by a glue homogenizing machine, and finally the sample is dried on a heating plate.

3. The method according to claim 2, wherein in step S1, the cleaning sequence is acetone, isopropanol, and then the cleaning is performed in a solution prepared from hydrogen peroxide and sulfuric acid, wherein the volume ratio of hydrogen peroxide to sulfuric acid is 1: 3.

4. the method according to claim 1, wherein in step S2, MoO₃The distance between the powder and the SiC substrate is 1-3 cm.

5. The method of claim 1, wherein the S powder and MoO in the step S2₃The mass ratio of the powder is 2: 1.

6. the method according to claim 1, wherein the step S3 includes: the tube furnace was evacuated to 0.2Pa using a vacuum pump and then subjected to more than 2 washings.

7. The method according to claim 1, wherein the step S4 includes: introducing Ar gas as protective gas at a certain flow rate into the quartz tube, heating the high-temperature region to 650-700 ℃ within 1h, heating the low-temperature region to 160-180 ℃, reacting at constant temperature for a period of time, and finally naturally cooling.

8. The method according to claim 7, wherein in the step S4, the Ar gas flow rate is 50sccm to 70 sccm.

9. The method according to claim 7, wherein the step S4 includes: introducing Ar gas as protective gas at a certain flow rate into the quartz tube, heating the high-temperature region to 650 ℃ within 1h, heating the low-temperature region to 160 ℃, reacting at constant temperature for a period of time, and finally naturally cooling and heating.

10. The method according to claim 9, characterized in that the isothermal reaction time is 4 h.

Technical Field

The invention belongs to the technical field of semiconductor materials, and particularly relates to a method for directly growing molybdenum disulfide (MoS) on a silicon carbide (SiC) substrate by a Chemical Vapor Deposition (CVD) method₂) A method of making a thin film.

Background

MoS because of its unique and excellent optoelectronic properties₂Has become the most interesting two-dimensional semiconductor material besides graphene. By reducing MoS₂Number of layers of film, MoS₂When becoming a monomolecular layer, the band gap will change from an indirect band gap to a direct band gap, MoS₂Will increase from 1.2eV to 1.8eV, thus exhibiting many excellent photovoltaic properties. MoS₂The film has high light responsivity, high conductivity, good gas sensitivity and the like, is one of ideal semiconductor materials for manufacturing detectors, sensors and the like, and is based on MoS₂Thin film devices have the advantages of low power consumption, high on-off ratio, low carrier mobility, etc. Therefore, compared with zero-bandgap graphene, bandgap-controllable MoS₂Will have greater application potential in the new generation of high performance nanoelectronic and optoelectronic devices.

Based on MoS₂The device of the/SiC heterojunction has excellent performances such as good rectification characteristic, optical responsivity, high thermal stability and the like, and high-performance MoS₂the/SiC heterojunction device has important significance, however, MoS is prepared on SiC at present₂The film is mainly prepared by MoS through mechanical stripping method, polymethyl methacrylate auxiliary transfer method and the like₂Transfer to SiC substrates, MoS prepared by these methods₂The film has the problems of uneven size, small area, poor heterojunction interface performance and the like, so that the practical application is difficult to realize, and the requirement of large-scale production cannot be met.

Disclosure of Invention

The invention aims to directly grow MoS on a SiC substrate₂Method of thin film to obtain high quality MoS of uniform size and large area₂The film overcomes the problems in the prior art.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

MoS directly growing on SiC substrate₂A method of making a film comprising the steps of:

s1: cleaning the SiC substrate;

s2: weighing sulfur S powder and MoO₃The powder is respectively arranged in a quartz boat, and the cleaned SiC substrate is put in a quartz boat filled with MoO₃In the quartz boat of the powder, MoO is filled in the quartz boat₃Placing the quartz boat containing S powder in the high-temperature region of the tube furnace, and placing the quartz boat containing S powder in the low-temperature region of the tube furnaceA zone;

s3: vacuumizing the tube furnace;

s4: introducing Ar gas as protective gas, heating the high-temperature region to 650-700 ℃, heating the low-temperature region to 160-180 ℃, reacting at constant temperature for a period of time, and then naturally cooling.

Further, the step S1 includes: the sample is respectively ultrasonically cleaned in acetone and isopropanol, then is soaked in a solution prepared from hydrogen peroxide and sulfuric acid, is soaked and washed for several times by deionized water, then the deionized water on the surface of the sample is thrown off by a glue homogenizing machine, and finally the sample is dried on a heating plate.

Further, in step S1, the cleaning sequence includes first cleaning with acetone and isopropanol, and then cleaning with a solution prepared from hydrogen peroxide and sulfuric acid.

Further, the volume ratio of hydrogen peroxide to sulfuric acid is 1: 3.

further, the SiC substrate had a size of 1cm × 1cm and a thickness of about 350 μm.

Furthermore, the selected acetone and isopropanol are analytically pure.

Further, the ultrasonic cleaning time of the substrate in the acetone solution was 5 min.

Further, the ultrasonic cleaning time of the substrate in the isopropanol solution was 5 min.

Further, the substrate is soaked in a solution prepared from hydrogen peroxide and sulfuric acid for 2 hours.

Further, the substrate is soaked in the deionized water for 5 min.

And further throwing the deionized water on the surface of the sample by using a spin coater, wherein the deionized water is firstly slowly thrown at the rotating speed of 500rmp for 5s and then quickly thrown at the rotating speed of 9000rmp for 5 s.

Further, the substrate was dried on a hot plate for 5 min.

Further, the temperature at which the substrate was dried on the heating plate was 100 ℃.

Further, in step S2, MoO₃The distance between the powder and the SiC substrate is 1-3 cm.

Further, MoO₃Powder andthe distance of the SiC substrate was 2 cm.

Further, in step S2, the S powder and MoO₃The mass ratio of the powder is 2: 1, the purity of S powder is not lower than 99.5 percent; MoO₃The purity of the powder is not less than 99.5%.

Further, step S3 includes: the tube furnace was evacuated to 0.2Pa using a vacuum pump and then subjected to more than 2 washings.

Further, the step S4 includes: introducing Ar gas as protective gas at a certain flow rate into the quartz tube, heating the high-temperature region to 650-700 ℃ within 1h, heating the low-temperature region to 160-180 ℃, reacting at constant temperature for a period of time, and finally naturally cooling.

Further, in the step S4, the flow rate of Ar gas is 50sccm to 70 sccm.

Further, the step S4 includes: introducing Ar gas at a certain flow rate into the quartz tube as protective gas, heating the high-temperature region to 650 ℃ within 1h, heating the low-temperature region to 160 ℃, reacting the quartz boat in the high-temperature region and the quartz boat in the low-temperature region at a distance of 36cm, and finally naturally cooling and heating.

Further, the isothermal reaction time was 4 hours.

Compared with the prior art, the invention has the beneficial technical effects that:

the method of the invention has simple operation and can directly grow high-quality MoS on the SiC substrate₂Thin film, grown MoS₂The film has the advantages of large area, uniform size, high growth speed and the like.

Drawings

FIG. 1 shows the direct growth of MoS on SiC substrate according to example 1 of the present invention₂Experimental setup diagram of the thin film;

FIG. 2 shows the growth of MoS according to example 1 of the present invention₂Raman map of the film;

FIG. 3 shows the growth of MoS according to example 1 of the present invention₂SEM image of the film;

FIG. 4 shows the growth of MoS according to example 1 of the present invention₂XRD pattern of the film;

FIG. 5 shows the growth of MoS according to example 1 of the present invention₂AFM images of the films.

The specific implementation mode is as follows:

the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. The raw materials used in the present invention are not particularly limited to manufacturers thereof. The doping concentration of the SiC substrate material used in the present invention is not limited. The chemical reagents used in the present invention are preferably analytically pure, the purity of the powdery material being as high as possible.

Example 1

Materials:

MoO₃powder 0.3g, MoO₃The purity of the powder is not lower than 99.5%;

0.6g of S powder, wherein the purity of the S powder is not less than 99.5%;

SiC substrate and MoO₃The distance of (c): 2cm

The preparation process comprises the following steps:

firstly, cleaning a sample, namely ultrasonically cleaning a cut SiC substrate by using acetone and isopropanol in sequence, and preparing a solution (H) prepared from hydrogen peroxide and sulfuric acid after ultrasonic cleaning for 5min₂O₂：H₂SO₄1: 3) soaking for 2h, soaking and washing for several times by using deionized water, then throwing the deionized water on the surface of the sample by using a glue homogenizing machine, and finally placing the substrate on a heating plate for drying. The SiC substrate had a size of 1cm by 1cm and a thickness of about 350 μm. The acetone and the isopropanol are analytically pure. The ultrasonic cleaning time of the substrate in the acetone solution is 5min, the ultrasonic cleaning time of the substrate in the isopropanol solution is 5min, the soaking time of the substrate in the solution prepared from hydrogen peroxide and sulfuric acid is 2h, and the soaking time of the substrate in deionized water is 5 min. And (3) throwing the deionized water on the surface of the sample by using a spin coater, slowly throwing the deionized water firstly at the rotating speed of 500rmp for 5s, and quickly throwing the deionized water secondly at the rotating speed of 9000rmp for 5 s. The drying time of the substrate on the heating plate was 5min, and the temperature of the substrate on the heating plate was 100 ℃.

Secondly, weighing and loading the sample, and weighing 0.3g MoO by using an electronic balance₃Powder and 0.6g of S powder are respectively placed in two quartz boats. Placing the cleaned SiC substrate in a container containing MoO₃Quartz boat of powder (SiC substrate located inMoO₃Downstream of the powder), the SiC substrate and MoO₃Is 2cm and is placed in the high temperature zone of the tube furnace; and placing the quartz boat for containing the S powder in a low-temperature area at the front end of the tube furnace, wherein the distance between the quartz boat in the high-temperature area and the quartz boat in the low-temperature area is 36 cm.

And thirdly, vacuumizing, namely vacuumizing the tube furnace to 0.2Pa by using a vacuum pump, then performing gas washing for 2 times, and vacuumizing until air in the quartz tube is exhausted.

Fourthly, reacting and growing, introducing high-purity Ar gas as protective gas with a certain flow rate into the quartz tube, controlling the flow rate of the gas to be 70sccm through the mass flow meter, heating the high-temperature area of the tube furnace to 650 ℃ within 1 hour, and heating the low-temperature area to 160 ℃. Reacting for 4 hours at constant temperature, and finally naturally cooling.

The device is shown in FIG. 1, the quartz boat containing S powder is placed in a low temperature zone, MoO₃And placing the quartz boat where the powder and the SiC substrate are located in a high-temperature area, and introducing Ar serving as protective gas into the quartz tube. For the grown MoS₂The film, this patent adopts X ray powder diffraction appearance (XRD), Raman spectroscopy (Raman), field emission Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) to carry out the characterization. FIG. 2 shows the growth of MoS on SiC substrate₂Raman mapping of thin films, MoS on SiC substrates₂Two characteristic peaks E of the film¹ _2gAnd A_1gAre respectively located at 382.13cm^-1And 408.31cm^-1The distance between two characteristic peaks is about 26.18cm^-1Indicates that six-layer MoS is synthesized₂A film. FIG. 3 shows MoS grown directly on SiC substrate₂A film SEM picture, which shows that a plurality of MoS with triangular morphology grows on the SiC substrate₂The film is single in appearance, large in size, uniform in size and large in area, and the side length of a triangle is about 2 mu m. FIG. 4 shows MoS growth on SiC substrate₂XRD patterns before and after the film, diffraction peak at 14.3 degrees corresponds to MoS₂(002) crystal face of the film. MoS growth on SiC substrate₂AFM image of the film is shown in FIG. 5, and MoS is seen₂The thickness of the film was 4.35nm and approximately six layers of MoS₂Film, the result of which is consistent with the test result of Raman chart.

The invention provides direct growth of MoS on SiC substrates₂The method of the invention has simple operation and can directly grow high-quality MoS on the SiC substrate₂Thin film, grown MoS₂The film has the advantages of large area, uniform size, high growth speed and the like.

The above description is 1 preferred embodiment of the present invention, and the embodiment is to help understanding the method and idea of the present invention, and modifications and improvements can be made to the present invention without departing from the experimental principle, and these are all included in the protection scope of the present invention.