Heavy Ion Elastic Recoil Detection Analysis of Silicon-Rich Silica Films

Abstract

Heavy ion elastic recoil detection (ERD) is shown to be a powerful tool for studying the deposition and processing of Si-rich silica films deposited by plasma enhanced chemical vapour deposition (PECVD). Such films are of interest for the fabrication of SiO2 layers containing silicon nanocrystals and are commonly deposited using SiH4 and N2O source gases. Heavy ion ERD reveals that as-deposited films can contain high concentrations of N, potentially reducing the efficacy of nanocrystal formation due to competing reactions between Si and N. This is believed to explain why high excess-Si concentrations are required to produce luminescent nanocrystals in such layers. Analysis of samples following high temperature (1200 °C) annealing also reveal the loss of H from the layers and highlight an experimental artefact associated with such high temperature processing.