Cost-effective synthesis of silicon carbide in atmospheric pressure microwave plasma*

Silicon carbide (SiC), due to its wide bandgap, is widely used in microelectronics applications such as high-power, -temperature, -voltage devices, and optoelectronics. Over the past decades, many production options based on epitaxial growth, physical and chemical vapor deposition have been implemented. Despite the variety of synthesis methods, such processes remain expensive and energy-consuming. This work proposes a simplified version of SiC synthesis based on the deposition of reaction products from the plasma phase of a microwave discharge. Tetramethylsilane feedstock diluted in a controlled flow of argon was used as a source. The reaction took place inside a quartz tube under the influence of an external microwave field. A sample of the material was deposited on a substrate in the air at atmospheric pressure and room temperature. The yield was an agglomerate of SiC particles encapsulated in a carbon shell with a 10-15 nm characteristic size. The used production method did not allow achieving stoichiometry of SiC due to the Si/C ratio of 1:4 in the precursor, which led to the formation of residual amorphous carbon and contamination of the specimen. This problem can be eliminated by further post-processing of the obtained material or by changing the precursor to an argon-silane gas mixture, which will be demonstrated.