Mechanism and energetics of self-interstitial formation and diffusion in silicon

Abstract

Recent work has suggested that prior determinations of diffusion mechanism and point defect thermodynamics in silicon have been affected by nonequilibrium effects stemming from uncontrolled adsorption-induced suppression of a pathway for defect creation at the surface. Through silicon self-diffusion measurements in ultrahigh vacuum in a short-time kinetic limit, the present work shows unambiguously that interstitials are the primary mediators of self-diffusion over the range $650--1000\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$, moving over distances of $5--9\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ before exchanging into the lattice. The Frank-Turnbull mechanism of interstitial formation does not play a significant role.