Evidence of a charge induced contribution to the sputtering yield of insulating and semiconducting materials

Following the recent observation in this laboratory of a charge induced damage effect in insulators under inert gas ion bombardment, the influence of the charge state of the beam (ion or atom) on the sputtering yield of insulating and semiconducting materials has been investigated. A series of sputter measurements has been carried out on Au, Ta2O5, Si, GaAs, and glass using calibrated ion and atom fluxes. For this purpose a recently developed gun capable of producing raster-scanned, microfocused energetic ion or atom beams was employed. While for the conductor Au, as expected, no effect was seen, for the remaining materials sputter yield increases of up to 150% were observed under ion bombardment which implies the existence of a substantial electronic sputtering effect in insulators and semiconductors due to low-energy ion bombardment.