Direct mapping of theCoSi2/Si(111) interface by ballistic-electron-emission microscopy and modulation spectroscopy

To map the interfacial structure of ${\mathrm{CoSi}}_2$/Si(111), the atomic thickness variations of epitaxial ${\mathrm{CoSi}}_2$ films were spatially resolved and determined using ballistic-electron-emission microscopy. Modulation spectroscopy was also used, and it showed not only thickness variations, but also strong lateral variations near the interfacial steps and dislocations. Also, a strong energy dependence of the quantum-size effects due to the transition from bound quantized subbands to resonances in ${\mathrm{CoSi}}_2$ was seen.