Ionization of trimethylsilane, (CH3)(3)SiH

Cross sections for electron impact ionization of trimethylsilane from thres hold to 70 eV have been measured using Fourier transform mass spectrometry. High resolution mass spectra show that the parent ion Si(CH3)(3)H+ is not formed by electron impact. Only one of the 15 ions produced by dissociative ionization lacks a silicon atom. The total ionization cross section is 1.5 X 10(-15) cm(2) at 70 eV.(CH3)(2)SiH+ and (CH3)(3)Si+ comprise over half o f the ions produced by electron impact, but charge transfer reactions of (C H3)(2)SiH+ and lighter ions yield (CH3)(3)Si+ at pressure-time product in t he 10(-7) Torr s range. The implication of this ion chemistry is that ion f luxes to the walls of trimethylsilane plasmas are predominantly (CH3)(3)Si. (Int J Mass Spectrom 184 (1999) 83-88) (C) 1999 Elsevier Science B.V.