Transient SIMS depth-profiles at the interface Si3N4/GaAs

Abstract

A transient secondary ion signal enhancement during sputtering through the interface of a two-layer target of Si3N4/GaAs could be demonstrated to be an artefact caused by the bombardment with oxygen ions, which were used as a primary beam. A simple model is established which describes ion-induced composition changes during sputtering (sputter-emission and recoil implantation from the surface, cascade mixing, and implantation of projectiles). The application of this model permits the simulation of internal profiles of a trace element, the matrix atoms and of implanted primary ions, and consequently the simulation of the emitted particle flux during sputtering. These calculations indicate an accumulation of implanted primary ions at the GaAs-side of the interface which considerably enhances the yield of positive secondary ions in this zone. The calculated response fits experimental data within a factor of less than 2.