HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY OF SI GE INTERFACIALSTRUCTURES/

A [110] cross-sectional high-resolution transmission electron microsco py (HREM) method for atomic scale observation of Si/Ge interfacial str uctures has been developed. The HREM image intensities of Si and Ge ar e theoretically investigated under various imaging conditions. The res ults show that their images exhibit strong contrast for an EM specimen thickness near the Ge extinction distance (14.8 nm) under a focus-set ting of -10 nm. This is due to the large difference in the {111} ampli tudes between Ge and Si. An EM specimen preparation technique in which chemical etching was used to remove ion milling artifacts was employe d to accomplish this observation. Using this HREM method, observations of the Si/Ge interfacial structure are achieved, giving information a bout interfacial ordering.