Structural Study of PtSi/(111)Si Interface with High-Resolution Electron Microscopy

The interface structure between PtSi and (111)Si has been clarified on an atomic scale for the first time, using a 1 MV high-resolution electron microscope. At the interface the transition from the PtSi lattice to the Si lattice is abrupt without the formation of any extra phase. Lattice fringe images show that the interface is heavily undulated and has atomic steps. Large lattice mismatch between PtSi and Si generates these atomic steps and extra half planes of PtSi. The observed relationship between the slope of the interface and the number of extra half planes can be explained by a simple model.