BALLISTIC-ELECTRON-EMISSION-MICROSCOPY INVESTIGATION OF HOT-CARRIER TRANSPORT IN EPITAXIAL COSI2 FILMS ON SI(100) AND SI(111)

The attenuation lengths lambda's of hot electrons in thin films of epitaxial CoSi2 on Si(100) and Si(111) were measured as a function of energy using constant-height-mode and constant-current-mode ballistic-electron-emission microscopy (BEEM). Between similar to 1 and similar to 3 eV above the Fermi energy, the lambda's were found to be significantly anisotropic and their energy dependencies differed strongly from the free-electron behavior. At higher energies, e(-)-e(-) scattering in CoSi2 was found to be dominant, giving a majority of the BEEM current and largely determining the spatial resolution of both forward and reverse BEEM imaging, both of which could bk used for direct mapping of interfacial steps. Also, constant-height-mode BEEM was used to investigate the interfacial transport across CoSi2/n-type Si(111), CoSi2/p-type Si(111), and CoSi2/n-type Si(100). Evidence for different interfacial structures of CoSi2/Si(100) was observed.