The changing behavior of the dielectric constant of a-SiC:H films deposited by remote PECVD with various deposition conditions using HMDS and PPCS

摘要

a-SiOC:H films were deposited by a remote PECVD (Plasma Enhanced Chemical Vapor Deposition) system using HMDS (Hexamethyldisilane) and PPCS (Polyphenylcarbosilane) as the precursor. PPCS precursor was synthesized using a Kumada rearrangement at 350 °C by KICET (Korea Institute of Ceramic Engineering and Technology). We compared the properties of film deposited using PPCS with that deposited using HMDS. H2 gas and C2H2 gas were used as the carrier gas and dilution gas, respectively. The deposition temperature was varied between 100°C-250 °C. The flow rate of the H2 carrier gas was varied from 3 to 100 sccm for a study of the deposition conditions which effects the film stoichiometry and dielectric constant of deposited films. The thickness of deposited films was measured by ellipsometry and the dielectric constant was examined by C-V measurements of deposited films. Using both sources without a C2H2 dilution gas led to the deposition of SiO2 films. The depositions using the C2H2 dilution gas caused a change of the carbon ratio and carbon hybridized bonds which play an important role in the change of the dielectric constant.