D–Si(111)(1×1) surface for the study of silicon etching in aqueous solutions

Abstract
Deuterium-terminated Si(111) surfaces are formed in a solution of KF and DCl in D2O. Infrared spectroscopy shows the surface to be flat with a D–Si bond normal to the surface. H–Si is formed preferentially to D–Si in a mixture of protonated and deuterated etchants. From the D-to-H exchange rate and the terrace width, we estimate the rate of the stepflow etching process to be 4.2 nm/s in Ar-sparged 40% NH4F solution. Dissolved O2 in the solutions substantially increases the D-to-H exchange rate by the formation of pits and the consequent increase in the step density.