In situ observation of oxidation and etching of silicon by ultra-high-vacuum transmission electron microscopy

O-2-Si surface reaction processes, such as oxidation and etching, have been observed in situ with a new ultrahigh-vacuum transmission electron microscope at atomic resolution. It was demonstrated that the etching occurs block by block and the oxidation starts from the terrace edge. Reconstructed Si surface structures appearing under clean vacuum conditions, such as Si(111)7 x 7 and Si(001)2 x 1 structures, have been also observed using this electron microscope on an atomic scale. We have demonstrated that this electron microscope is useful for studies of the dynamic behavior of surfaces.