ION-MOLECULE REACTIONS IN THE SILANE-AMMONIA SYSTEM

Fourier transform mass spectrometry was used to investigate the products and rate constants of reactions of ions derived from SiH4 with ammonia and of ions derived from NH3 with silane. Eliminative addition and proton transfer are the primary channels observed in the SiHx+ + NH3 reactions, while charge- and hydrogen-transfer channels dominate in the NHx+ + SiH4 reactions. The SiHxN+ product ions, unlike analogous ions with silicon backbones, do not react at comparable rates either with silane or with ammonia. This leads to the conclusion that in contrast to pure silane plasmas, ionic chain reactions should contribute little to the mass transport in the silane-ammonia silicon nitride deposition plasmas. © 1990 American Chemical Society.