Oblique cone formation in Ge by Ar+ sputtering

Sharp oblique cones are only formed on polished germanium surfaces by 30 keV Ar+ bombardment, in the presence of tungsten seed atoms; substantiating Wehner's hypothesis that higher melting point seed material is the crucial factor for cone formation. The morphology of the cone is characterized by the formation of a sloped ridge, consistent with the observations of earlier workers. Moreover, some strange wing-like structures are associated with these cones. (author)