Thin-Film Deposition of Silicon-Incorporated Diamond-Like Carbon by Plasma-Enhanced Chemical Vapor Deposition Using Monomethylsilane as a Silicon Source

We have deposited Si-incorporated diamond-like carbon (DLC) films by radio-frequency plasma-enhanced chemical vapor deposition using methane, argon, and monomethylsilane (MMS: CH3SiH3) as a silicon source, and have investigated the structural and mechanical properties of the films. The deposition rate and Si atomic fraction [Si/(Si + C) in the DLC films increased with increasing MMS flow ratio. The Si fraction was approximately 13% at a MMS flow ratio [MMS/(MMS + CH4)] of 3%, showing that the deposition using a combination of CH4 and MMS produces films with high Si content compared with those deposited using conventional C and Si sources. The Si fraction was also found to increase with a decrease in Ar flow rate under a constant MMS flow ratio. Many particles composed mainly of Si, whose size was 0.3-1 mu m in diameter, were observed on the surface when deposition was carried out at MMS flow ratios of 15 and 30%. Compressive internal stress in the films decreased with the MMS flow ratio and/or with the Ar flow rate. The decrease in internal stress is probably due to the relaxation of a three-dimensional rigid network by the formation of Si-C and Si-H bonds in the films are well as Ar+ ion bombardment. [DOI: 10.1143/JJAP.47.8491]