Reactions of bare silicon cluster ions: Prototypical deposition and etching versus cluster size.

Prototypical silicon deposition and etching reactions have been observed in gas phase reactions of size selected bare silicon cluster ions with various neutral reagents at room temperature. Etching reactions occur in reactions with certain halogen or oxygen containing reagents. For example, NO sub 2 and XeF sub 2 react to destroy the silicon clusters by sequential loss of a single silicon atom. Deposition type reactions occur with silanes, e.g. CH sub 3 SiH sub 3, and increase the number of silicon atoms in the cluster. Overall the reactivity of small silicon cluster ions correlates the chemistry which occurs at two distinct types of dangling bonds in the clusters: either a lone pair of electrons or a single radical electron. This review of our recent work summarizes a talk given in the symposium on Photon, Beam and Plasma Stimulated Chemical Processes at Surfaces at the December, 1986 Meeting of the Materials Research Society and will be published in the conference proceedings.