Gas-phase ion chemistry of silane with ethane and ethyne

Silane-ethane and silane-ethyne systems have been studied by ion trap mass spectrometry and the variation of the abundances, with reaction time, of th e ions containing silicon and carbon together in 5:1, 1:1 and 1:5 mixtures, have been reported. The best ion yield, which increases with the total pre ssure, is observed for 1:1 silane-ethyne mixture. Reaction mechanisms and r ate constants of the first nucleation processes have been determined. In Si H4-C2H2 systems, the formation of ions containing new Si-C bonds occurs sta rting mainly from SimHn+ ions in the first steps, whereas the SimCnHp+ clus ter species further reacts with high efficiency in processes with ethyne. ( C) 1999 Elsevier Science S.A. All rights reserved.