Mechanism of electron-irradiation-induced recrystallization in Si

Abstract

It has recently become clear that electron irradiation can recrystallize amorphous zones in semiconductors even at very low temperatures and even when the electron beam energy is so low that it cannot induce atomic displacements by ballistic collisions. We study the mechanism of this effect using classical molecular dynamics augmented with models describing the breaking of covalent bonds induced by electronic excitations. We show that the bond breaking allows a geometric rearrangement at the crystal-amorphous interface which can induce recrystallization in silicon without any thermal activation.