The Effect of Grown-In Point Defects on Sb Diffusion in MBE-Grown Si and Sige

Abstract

ABSTRACTThe diffusion of antimony in Si and SiGe under the influence of grown-in point defects is studied in this work. The layers were grown by very low temperature MBE, and the diffused profiles measured using SIMS analysis. Fast diffusion of Sb is observed in both Si and SiGe. and is thought to be caused by grown-in point defects, specifically vacancies, arising from the very low temperature MIBE growth. The vacancies may be removed by heat treatments. and it was found that the processing the samples received before the heat treatments caused the most substantial diffusion. Comparison of the diffusivities for inert diffusion at 850°C following the heat treatments suggests 30 minutes at 800°C is sufficient to remove the majority of the grown-in defects. The diffusion of Sb in Si is thus demonstrated to be a very sensitive monitor of grown-in vacancies, and dopants which diffuse at least partly by vacancy mediated processes would be expected to be affected by this effect.