Interface-limited grain-boundary motion during ion bombardment.

Abstract

Ion bombardment of polycrystalline Ge, Si, and Au films results in grain-boundary migration rates which are weakly temperature dependent, and which greatly exceed thermal migration rates. The enhanced migration rate is proportional to the rate of nuclear collisions at or very near the grain boundary. We present a transition-state model which accounts for the observed kinetics of grain-boundary migration during bombardment. The ratio of atomic jumps at grain boundaries to the local collision-induced Frenkel-defect generation rate is characteristic of each material.