The conditions required to prepare ideal flat H-S(111) surfaces by chemical etching in 40% NH 4 F are examined using ex-situ atomic force microscopy (AFM) observations. We compare the topography of samples when the polished and eventually the rough (back) sides of an n-type Si(111) wafer are exposed to an etching solution. It is demonstrated that using an oxygen-free solution and exposing the two faces to the etching solution are two essential conditions for obtaining a surface that is free of etch pits. The result is independent of the angle of the miscut. The influence of the direction of the miscut on the morphology of step edges is investigated using the correlation between images and XRD characterizations at grazing incidence.