Resonant electron tunneling and related charging phenomena in metal–oxide–$p^+$-Si nanostructures

The j–V characteristics of the Al/thermal or electrochemical SiO$_2$(2–4 nm)/heavily doped $p^+$-Si nanostructures operating as a resonant-tunneling diode were measured and theoretically analyzed. The characteristics have specific features in the form of current steps and peaks, which are caused by electron transport between the silicon valence band and metal through discrete levels of the quantum well formed by the $p^+$-Si conduction band and SiO$_{2}/p^{+}$-Si interface. Resonant tunneling through the surface state levels and the appearance of a charge near this interface under certain conditions are discussed.