Electron transport measurements of Schottky barrier inhomogeneities

We report nonmonotonicities in the low-temperature current versus gate voltage characteristics of PtSi/Si Schottky Barrier metal-oxide-semiconductor field-effect transistors. Direct tunneling through the Schottky barrier is shown to limit the current and be superimposed with resonant peaks and oscillations. These structures are attributed to resonant tunneling through impurities located close to the interface and nonuniformities of the heterojunction. We thus demonstrate barrier height variations in electron transport through a relatively large metal/semiconductor contact area. The inhomogeneities result in different average Schottky barrier heights between devices, and cause height variations as a function of carrier concentration within a metal/semiconductor interface.