Fragment Ions of Dimethylsilane Produced by Hot Tungsten Wires

Fragment ions produced from dimethylsilane with a hot tungsten wire (i.e., catalyzer) in catalytic chemical vapor deposition (Cat-CVD, which is also known as hot wire CVD) processes are identified with a use of a low-energy mass analyzed ion beam system. The mass analysis shows that dominant fragment ions from dimethylsilane are H₁⁺, H₂⁺, CH₃⁺, Si⁺, SiH₃⁺, SiCH₄⁺, SiC₂H⁺, and SiC₂H₇⁺. The energy distributions of these ions are also measured. It is found that the spreads of the energy distributions are narrow and no energetic ions are produced, suggesting that the produced ions are unlikely to cause any significant damage to the deposited films in actual dimethylsilane Cat-CVD processes. The ion production rates are found to be strongly dependent on the catalyzer temperature.