Etching of SiC by energetic F2: Molecular dynamics simulation

Molecular dynamics (MD) simulations were performed to investigate F2 continuously bombarding silicon carbide (SiC) surfaces with energies in the range of 50–200 eVat normal incidence and room temperature. The Tersoff–Brenner form potential was used. The simulation results show that the uptake of F atoms, the etch yields of C and Si from the initial substrate, and the surface structure profile are sensitive to the incident energy. Like occurrence in Si etching, steady-state etching is observed and an F-containing reaction layer is formed through which Si and C atoms are removed. A carbon-rich surface layer after bombarding by F2 is observed which is in good agreement with experiments. In the reaction layer, SiF in SiF2 species are dominant; with increasing incident energy, the total fraction of SiF and SiF2 increases, while the amount of SiF3 and SiF4 decreases. Finally, etching mechanisms are discussed.