Epitaxial crystallization of a-Si and a-GaAs induced by low-energy ion bombardments

Abstract

Properties of the ion-beam-induced epitaxial crystallization (IBIEC) of amorphous Si layers with a thickness of about 170nm and amorphous GaAs layers with a thickness of about 110nm formed by As ion implantations have been investigated by using Ar and Kr ions with their projected ranges within the amorphous layer thicknesses. Recrystallization of the amorphous layers due to bombardments of these ions was observed to proceed in a layer-by-layer growth manner. After eliminating the sputtering effect, growth rates per ion fluence both for Si and GaAs were observed to have pseudo-linear dependences on incident ion energy for Ar and Kr bombardments, whereas growth rates per nuclear energy deposition density at the crystalline-amorphous interface showed to vary strongly as a function of incident ion energy. Present results can suggest a crucial role of formation of defects in the amorphous layer and their migration to the interface in IBIEC of Si and GaAs.