Microstructure of nanocrystalline SiC films deposited by modified plasma-enhanced chemical vapor deposition

Abstract Thin films of nanocrystalline silicon carbide (nc-SiC) were deposited by a modified plasma-enhanced chemical vapor deposition. The source gases were silane, methane and hydrogen. These stoichiometric films were achieved at a hydrogen dilution ratio (SiH4+CH4)/H2 of 2%, a gas ratio (SiH4/CH4) of 10%, a power density of 4 W/cm2, a bias pretreatment of 250 V for 10 min, and then a bias of 100 V at a deposition temperature of 300 °C. Characterizations by using transmission electron microscopy and Raman spectroscopy revealed that these nc-SiC films are composed of microcolumnar crystallites that have a mean size of 16 nm in diameter and are encapsulated by amorphous networks. The as-grown films have optical transmittances of 83% at 682 nm and 95% at 1844 nm.