Solid Phase Epitaxy Process Of Ar-Ion Bombarded Silicon Surfaces and Recovery of Crystallinity by Thermal Annealing Observed With Scanning Tunneling Microscopy

Abstract

ABSTRACTThe solid-phase epitaxy (SPE) process of Ar+-ion bombarded Si (001) surfaces and recovery of crystallinity by thermal annealing are studied “in situ” by using a scanning tunneling Microscope (STM). As-bombarded surfaces consist of grains of 0.63–1.6 nm in diameter. The grains gradually coalesce and form clusters of 2–3.6 nm in diameter at annealing temperature of 245° C (2×1) and (1×2) reconstructed regions surrounded by amorphous regions are partially observed on the surface by prolonged annealing, which suggests the onset of SPE. Successive observation reveals that the smoothing of the surface occurs layer by layer. As annealing temperature is raised up to 445 °C, the amorphous layer epitaxially crystallizes up to the topmost surface, and (2×1) reconstructed surface with Monatomic-height steps is observed. The smoothing of the surface structures and the formation of nucleation of Si islands are observed during annealing at 500 °C.