Scanning tunneling microscopy study of carbon and hydrogen reactions with Si(111) in ultrahigh vacuum

Abstract

Carbon is deposited onto a Si(111) surface in ultrahigh vacuum by three methods: hydrocarbon exposure of a heated sample, contamination by the residual gases in the chamber and carbon evaporation by resistively heating carbon fibers. The scanning tunneling microscope shows that for all three methods the result of heating the sample with deposited carbon to 1000 °C is a surface covered by identically shaped objects which we interpret as tip images formed by sharp clusters of β‐SiC on the surface. The SiC crystallites and the Si surface can be etched by exposure to atomic hydrogen. After large exposures the Si surface becomes rough and possibly porous.