Mechanisms of thermally induced dewetting of ultrathin silicon-on-insulator

Abstract

Annealing of ultrathin silicon-on-insulator drives the formation of pinholes in the Si template, which in turn triggers a dewetting of the monocrystalline Si slab that is strongly affected by its crystallographic structure. An initial phase of well-defined square openings in the Si is followed by a hierarchical sequence of more complex branched shapes of the dewetting front. Annealing temperatures of about $800°\mathrm{C}$ , near the onset of significant thermally activated mass transport, drive a slow and controlled evolution that allows us to identify the mechanism underlying the dewetting and explain the spontaneous formation of well-defined Si patterns at submicron dimensions.