In Situ STM Characterization of Step-Bunching on Miscut Si(111) Surfaces in Fluoride Solutions

The immersion of Si surfaces in fluoride solutions results in the formation of a hydrogen passivated surface. The resulting surface morphology is dependent on the solution composition and the crystallographic orientation of the surface. Etching of miscut Si~111! in fluoride solutions can lead to the formation of mesa-like features. In this article we show that these features are due to the formation of step bunches during the etching process. The density of these features is dependent on the etch rate, the applied potential, and the fluoride ion concentration of the etching solution.