Method for growing CuCrS2 on amorphous silicon dioxide substrate

Abstract

The invention discloses a method for growing CuCrS2 on an amorphous silicon dioxide substrate. According to the method, the CuCrS2 two-dimensional material is directly grown on the SiO2 substrate in situ, the CuCrS2 material is tightly combined with the silicon wafer, and the stability is good. Therefore, the operation can be directly carried out on the silicon wafer during the subsequent device preparation, the material transfer step required in the subsequent device preparation and rear-end integration when the mica substrate is used for generating the CuCrS2 material is reduced, the production time is shortened, the production cost is reduced, and the production efficiency is improved; and meanwhile, the compatibility of the CuCrS2 material and a CMOS (Complementary Metal Oxide Semiconductor) device is obviously improved.

Description

Technical Field

[0001] The invention relates to the field of semiconductor material physics and device technology, and in particular to a method for growing CuCrS2 on an amorphous silicon dioxide substrate. Background Art

[0002] CuCrS2 is a compound semiconductor material with important potential application value. It belongs to the transition metal dichalcogenide family, and its crystal structure and composition give it unique physical and chemical properties. In the field of optoelectronics, CuCrS2 has a suitable bandgap width and can effectively absorb photons in the visible light range, which makes it have potential application prospects in light detection and other aspects. In the field of ferroelectrics, CuCrS2 has in-plane and out-of-plane ferroelectricity, and its ferroelectricity comes from the deviation displacement of Cu atoms between CrS2 layers. This ferroelectric property makes CuCrS2 have potential application prospects in ferroelectric memory devices, sensors and other fields. For example, it can be used to prepare ferroelectric memory to achieve high-speed storage and reading of data.

[0003] At present, the most common CuCrS2 growth substrate is mica, which can be easily peeled into thin sheets of uniform thickness. Flat sheets of different thicknesses can be obtained according to industrial requirements, which is conducive to the precise control of the thickness and quality of the grown material. However, the manufacture of CMOS devices involves complex process steps such as lithography, etching, and doping. These processes are optimized and designed based on traditional semiconductor substrate materials and process systems. As a substrate material, mica has different physical and chemical properties from traditional semiconductor substrates, making it impossible to directly apply existing CMOS integration processes to device preparation on mica substrates. Summary of the invention

[0004] The object of the present invention is to solve the above technical problems and provide a method for growing CuCrS2 on an amorphous silicon dioxide substrate.

[0005] The technical solution adopted by the present invention is as follows: A method for growing CuCrS2 on an amorphous silicon dioxide substrate comprises the following steps:

[0006] S1. Cut the amorphous silicon dioxide substrate according to the size of the corundum boat and clean it;

[0007] S2, mixing copper powder, chromium powder and sodium chloride uniformly and grinding them to obtain a metal salt mixture and placing it in a corundum boat; placing sulfur powder in another corundum boat;

[0008] S3, placing the two corundum boats in S2 into a dual-temperature zone CVD tube furnace in sequence, placing the corundum boat containing sulfur powder in the upstream temperature zone of the airflow, and placing the corundum boat containing the metal salt mixture in the downstream temperature zone of the airflow; placing the pre-cut amorphous silicon dioxide substrate in S1 upside down just above the metal salt mixture; placing furnace plugs upstream and downstream of the tube furnace, and sealing the tube furnace;

[0009] S4. Introduce 500 sccm argon gas into the dual-zone CVD tube furnace for 10 minutes to clean the environment inside the furnace tube, and then change the gas flow to 50 sccm until the reaction is completed and the furnace tube is cooled, then turn off the argon gas; when the gas flow is changed to 50 sccm, start the dual-zone CVD tube furnace, control the temperatures of the upstream and downstream temperature zones respectively, react, and grow CuCrS2 samples on silicon wafers.

[0010] Preferably, the mass ratio of copper powder, chromium powder and sodium chloride in S2 is 5:5:1.

[0011] Preferably, the sulfur powder is 200mg to 300mg.

[0012] Preferably, the temperature of the upstream temperature zone of the dual-temperature zone CVD tube furnace in S4 is set as follows: a. raising the temperature to 850°C within 30 minutes; b. maintaining 850°C for 10 minutes; c. turning off the heating resistance wire and allowing the temperature to naturally drop to room temperature.

[0013] Further preferably, the temperature of the downstream temperature zone of the dual-temperature zone CVD tube furnace in S4 is set as follows: a. raising the temperature to 200°C within 30 minutes; b. maintaining 200°C for 10 minutes; c. turning off the heating resistance wire and allowing the temperature to naturally drop to room temperature.

[0014] The present invention provides a method for growing CuCrS2 on an amorphous silicon dioxide substrate. The metal salt mixture obtained by uniformly mixing and grinding copper powder, chromium powder and sodium chloride is placed in the downstream temperature zone of the airflow of a dual-temperature zone CVD tube furnace; sulfur powder is placed in the upstream temperature zone of the airflow of the dual-temperature zone CVD tube furnace, and then the pre-cut amorphous silicon dioxide substrate is turned upside down directly above the metal salt mixture. When the tube furnace is started to heat, sodium chloride (NaCl) will form ions after melting, and these ions will interfere with the binding force between copper (Cu) and chromium (Cr) atoms. During the melting process, atoms need to overcome the forces between each other to change from solid to liquid, and Na + The presence of Cl- ions will weaken the bonding between Cu and Cr atoms, making it easier for the atoms to obtain enough energy to enter the liquid state, thereby lowering the melting point of the mixture.

[0015] The melting point of Cu powder is about 1083℃-1084.6℃, and the melting point of Cr powder is about 1857℃. After adding NaCl, the mixture can melt and gasify at 850℃ to form metal atomic vapor, which reacts chemically with the sulfur (S) powder vapor brought by the upstream gas to form CuCrS2 and precipitate on the surface of the silicon wafer, thereby allowing CuCrS2 to grow in situ on the silicon dioxide substrate.

[0016] The beneficial effects of the present invention are:

[0017] 1. In the present invention, silicon dioxide is used as the substrate for the in-situ growth of CuCrS2. CuCrS2 has good adhesion to silicon dioxide. Therefore, the CuCrS2 in the present invention can better adhere to the surface of the silicon wafer, prevent the CuCrS2 material from falling off or peeling off during the growth process, ensure the close bonding between the growing material and the substrate, and improve the stability and reliability of the CuCrS2 material.

[0018] 2. The method of the present invention grows CuCrS2 two-dimensional material directly on a SiO2 substrate, and the subsequent device preparation can be directly performed on the silicon wafer, avoiding the need to transfer the CuCrS2 material to a silicon wafer for subsequent operations when mica is used as a substrate to generate the CuCrS2 material, thereby effectively reducing the processing steps and processing time, saving production costs, and improving production efficiency; at the same time, the compatibility of the CuCrS2 material with CMOS devices is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of upstream temperature changes;

[0020] Figure 2 It is a schematic diagram of downstream temperature changes;

[0021] Figure 3 This is an optical picture of CuCrS2 on a silicon dioxide substrate;

[0022] Figure 4 This is the SEM image of CuCrS2 material;

[0023] Figure 5 Schematic diagram of a two-terminal device constructed directly on a silicon wafer with CuCrS2 grown on it.

[0024] Figure 6 This is the output characteristic curve of CuCrS2 material. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] Step 1, cutting the amorphous silicon dioxide substrate according to the size of the corundum boat and cleaning it;

[0028] Step 2: Weigh copper powder (10 mg), chromium powder (10 mg) and sodium chloride (2 mg) in a mass ratio of 5:5:1, mix and grind to obtain a metal salt mixture, and put it into a corundum boat; then weigh sulfur powder (200 mg) and put it into another corundum boat;

[0029] Step 3: Place two corundum boats into a dual-temperature zone CVD tube furnace in sequence. The corundum boat containing sulfur powder is placed in the upstream temperature zone of the airflow, and the corundum boat containing the metal salt mixture is placed in the downstream temperature zone of the airflow. Place the cleaned pre-cut amorphous silicon dioxide substrate upside down directly above the metal salt mixture. Place furnace plugs upstream and downstream of the tube furnace, and seal the tube furnace.

[0030] Step 4: introduce 500 sccm argon gas into the CVD tube furnace for 10 minutes to clean the environment inside the furnace tube, and then change the gas flow to 50 sccm until the reaction is completed. After the furnace tube is cooled, turn off the argon gas to prevent gas backflow and pollute the environment inside the tube. When the gas flow is changed to 50 sccm, start the dual-temperature zone tube furnace for growth. The dual-temperature zone tube furnace in this embodiment is the Hefei Kejing OTF-1200X dual-temperature zone tube furnace.

[0031] The upstream and downstream temperature zones are controlled separately. The temperature of the upstream temperature zone is set as follows: a. Raise the temperature to 850°C within 30 minutes; b. Maintain 850°C for 10 minutes; c. Turn off the heating resistor and let the temperature drop to room temperature naturally in about 3 hours. Figure 1 .

[0032] The temperature of the downstream temperature zone is set as follows: a. Raise the temperature to 200℃ within 30min; b. Maintain 200℃ for 10min; c. Turn off the heating resistor and let the temperature drop to room temperature naturally in about 3h. Figure 2 .

[0033] Step 6: Take out the corundum boat and silicon wafer, and observe the CuCrS2 sample on the silicon wafer. Figure 3 , SEM spectrum as Figure 4 .

[0034] Example 2

[0035] 1. A two-terminal device is constructed directly on the silicon wafer grown with CuCrS2 prepared in Example 1, such as Figure 5 shown.

[0036] 2. The CuCrS2 sample prepared in Example 1 was prepared into a two-terminal device, and the output characteristic curve was obtained as follows: Figure 6 .

[0037] In summary, the method for in-situ growth of CuCrS2 material on silicon wafer in the present invention is simple and easy to operate, and the CuCrS2 material prepared by the method is tightly combined with the silicon wafer, and can be directly operated on the silicon wafer during subsequent device preparation, thereby reducing the steps of material transfer required in subsequent device preparation and back-end integration when generating CuCrS2 material using mica substrate, shortening the production time, reducing the production cost, and improving the production efficiency.

[0038] The specification and drawings of the present invention are considered to be illustrative rather than restrictive. On the basis of the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features according to the disclosed technical content without creative labor, all of which are within the protection scope of the present invention.

Claims

1. A method for growing CuCrS2 on an amorphous silicon dioxide substrate, characterized in that: The following steps are involved: S1. Cut the amorphous silicon dioxide substrate according to the size of the corundum boat and clean it; S2, mixing copper powder, chromium powder and sodium chloride uniformly and grinding them to obtain a metal salt mixture and placing it in a corundum boat; placing sulfur powder in another corundum boat; S3, placing the two corundum boats in S2 into a dual-temperature zone CVD tube furnace in sequence, placing the corundum boat containing sulfur powder in the upstream temperature zone of the airflow, and placing the corundum boat containing the metal salt mixture in the downstream temperature zone of the airflow; placing the pre-cut amorphous silicon dioxide substrate in S1 upside down just above the metal salt mixture; placing furnace plugs upstream and downstream of the tube furnace, and sealing the tube furnace; S4. Introduce 500 sccm argon gas into the dual-zone CVD tube furnace for 10 minutes to clean the environment inside the furnace tube, and then change the gas flow to 50 sccm until the reaction is completed and the furnace tube is cooled, then turn off the argon gas; when the gas flow is changed to 50 sccm, start the dual-zone CVD tube furnace, control the temperatures of the upstream and downstream temperature zones respectively, react, and grow CuCrS2 samples on silicon wafers.

2. The method according to claim 1, characterized in that The mass ratio of copper powder, chromium powder and sodium chloride in S2 is 5:5:

1.

3. The method according to claim 1, characterized in that The sulfur powder is 200mg to 300mg.

4. The method according to claim 1, characterized in that: The temperature of the upstream temperature zone of the dual-temperature zone CVD tube furnace in S4 is set as follows: a. raising the temperature to 850° C. within 30 minutes; b. maintaining 850° C. for 10 minutes; c. turning off the heating resistance wire and allowing the temperature to naturally drop to room temperature.

5. The method according to claim 1, characterized in that The temperature of the downstream temperature zone of the dual-temperature zone CVD tube furnace in S4 is set as follows: a. Raise the temperature to 200° C. within 30 minutes; b. Maintain 200° C. for 10 minutes; c. Turn off the heating resistance wire and let the temperature drop naturally to room temperature.

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