Scattering and ion emission from insulator films

Abstract

To determine the effect of the surface potential of dielectric samples on the yield of positive ions during ion irradiation, we studied the dependence of the current of secondary particles on the thickness of dielectric films. It is shown that the yield of positive secondary particles increases significantly with increasing thickness if the film charging potential does not exceed the breakdown value determined by the electrical strength of the film. An indirect confirmation of the film charging in these experiments is the time dependence of the current from the sample holder. An experimental evaluation of the apparatus effect caused by the emission of secondary electrons from a hemispherical collector has been carried out. Possible mechanisms of the observed phenomena are discussed.