CHEMICAL BONDING AND MORPHOLOGY OF THIN CARBON FILMS GROWN ON SiC SURFACE VIA THE CARBIDE-DERIVED CARBON (CDC) PROCESS

摘要

We have investigated the effect of treatment of silicon carbide ceramic in a chlorine containing gas mixture. Due to the more energetically favored reaction of Cl_2 with Si rather than C, selective etching of the SiC surface takes place, leading to the formation of a carbide-derived carbon (CDC) film. XPS, Raman spectroscopy, AES and SEM studies of the chemical conversion of single crystal SiC and industrial polycrystalline silicon carbide surfaces treated with different gas concentrations and different temperatures are discussed. XPS analysis of the carbon C1s fundamental peak and the valence band shows that CDC films are not phase pure but consist of a mixture of sp2 and sp3 bonded carbon. Differences observed in the conversion rate and phases formed on different types of SiC substrates (single crystal or industrial ceramics) are likely due to grain boundary and surface morphology effects.