Distortion of na-concentration profiles in thin glassy surface layers by ion bombardment

Abstract

Abstract The intensity/time plots of the photon emission of excited Na atoms recorded during the continuous removal of thin Na2O-containing glassy layers by an ion beam allow for the analysis of the Na2O concentration profiles in these layers. Different intensity/time plots were obtained when changing the angle of incidence β of the ions or applying different constant β during the ablation of thin Na2O-containing glassy layers by positive 5.6 keV Ne+, Ar+ and Xe+ ions. These differences indicated that the concentration of Na is changed by a drift of Na+ ions caused by a positive space charge below the ion-bombarded surface. The field strength of the space charge was greatest for Ne+ ions, smallest for Xe+ ions. Simultaneously, a repulsive or an attractive field strength acts on positive Na ions within the thin layer if the value of the dielectric constant e in the thin layer is greater or smaller than in the substrate respectively. The influence of the drift on the profiles could be separated from that of...