Mechanism of Ion-Induced Solid-Phase Crystallization and Amorphization

Abstract

ABSTRACTA mechanism is proposed to explain ion-induced solid-phase epitaxial growth (SPEG). It is argued that radiation-enhanced diffusion in amorphous solid is the cause of ion-induced SPEG at relatively low temperatures. The atoms in the amorphous solid near the crystalline/amorphous interface adjust their positions to lattice sites due to a free energy decrease associated with the transformation from amorphous to crystalline solid. An expression for the velocity of ion-induced SPEG is derived. At low temperatures and high irradiation dose rates, a large number of atoms in the lattice gets displaced and the free energy of the crystalline solid can increase to such a value that the crystalline/amorphous interface may remain stationary. It is shown that the dose rate at which the interface remains stationary increases with the temperature, following an Arrhenius dependence.