Defect Trapping and Precipitation Processes During Annealing of Cu and Au Implanted Si

Abstract

AbstractThe behaviour of metallic impurities in Si is an issue of primary concern in advanced device processing. This paper addresses the annealing behaviour of Cu and Au in Si when nanocavities are present within the substrate as potential gettering and precipitation sites. In-situ, ‘hot’ Rutherford backscattering has been used to study metal accumulation to cavities at the annealing temperature. Transmission electron microscopy has been used to study the final microstructure of the Au-Si and Cu-Si system. A range of interesting phenomena have been observed, including very efficient transient gettering of both Cu and Au to cavities at the annealing temperature and precipitation of second phases at cavities. Dissolution of accumulated metal from defect bands into solution occurs for long-time annealing. This behaviour is discussed in terms of supersaturated solid solubility processes, diffusion, defect-trapping and precipitation of Cu and Au in Si.