Molecular dynamics simulations of CF3 etching of SiC

Molecular dynamics simulations were performed to investigate CF3 continuously bombarding SiC surfaces with energies of 100, 150 and 200 eV at normal incidence and room temperature. The simulated results show that the etching rates of Si and C atoms increase linearly with the incident energy. The etch rate of Si atoms is much more than that of C atoms. A carbon-rich surface layer is observed which is in good agreement with experiments. Under bombarding by CF3, an F-containing reaction layer is formed through which Si and C atoms are removed. In reaction layer, SiF and CF species are dominant. The formation mechanisms of ejected products are discussed. In etching products, SiF3 is dominant. It is found that etching of C atoms in SiC is controlled by physical sputtering, while etching of Si atoms in SiC is controlled by chemical sputtering.