Spatial variations of hot-carrier transmission acrossCoSi2/Si interfaces on a nanometer scale

In situ ballistic-electron-emission microscopy (BEEM) and spectroscopy have been performed at 77 K on epitaxial ${\mathrm{CoSi}}_2$ films on n-Si(100) and Si(111) of both doping types. Two different mechanisms have been identified, by which structural defects at these interfaces give rise to variations of the carrier transmission across the interface on a nanometer scale: On ${\mathrm{CoSi}}_2$/Si(111) interfacial misfit dislocations locally enhance the scattering probability at the interface. By the same mechanism individual interfacial point defects can be resolved in BEEM images. No variations of the Schottky barrier have been observed at this interface. In contrast, on ${\mathrm{CoSi}}_2$/Si(100), certain interfacial dislocations and other defects lower the Schottky barrier by up to 0.1 eV on a nanometer scale. © 1996 The American Physical Society.