Temporal Evolution of Ion Fragment Production from Dimethylsilane by a Hot Tungsten Wire and Compounds Deposited on the Tungsten Surface

Abstract

Temporal evolution of ion fragment production from gaseous dimethylsilane in contact with a hot tungsten wire was measured with the use of a low-energy mass analyzed ion beam system for the study of catalytic chemical vapor deposition (Cat-CVD, which is also known as hot wire CVD) processes. The X-ray diffraction and X-ray photoelectron spectroscopic measurements showed that silicon carbide and tungsten carbide compounds had been formed on the tungsten wire surface during the process. When the tungsten temperature was set to 2090 °C, the production of small fragment ions from dimethylsilane such as CH3+ and Si+ decreased while that of large fragment ions (SiC2H7+) hardly changed or sometimes increased within a few hours after the introduction of a dimethylsilane gas. The change of such fragmentation rates during the process is likely to have been caused by the surface modification of the tungsten wire.