Precursor mechanism for interaction of bulk interstitial atoms with Si„100..

In the same way that gases react with surfaces from above, solid-state point defects such as interstitial atoms can react from below. Little attention has been paid to this form of surface chemistry. Recent bulk selfdiffusion measurements near the Si 100 surface have quantified Si interstitial annihilation rates, and shown that these rates can be described by an annihilation probability that varies by two orders of magnitude in response to saturation of surface dangling bonds by submonolayer gas adsorption. The present work shows by modeling that the interstitial annihilation kinetics are well described by a precursor mechanism in which interstitials move substantial distances parallel to the surface before incorporation.