Enhancement of minority carrier supply in a resonant-tunneling metal-insulator-silicon capacitor

Abstract

The effect of enhancement of the electron concentration in the near-surface quantum well owing to a resonant tunneling between the semiconductor and the metal is analyzed theoretically. The range of parameters (acceptor concentration and insulator thickness) wherein such an electron-supplying mechanism becomes plausible is defined. Generally, the supply effect can be expected for a doping between (5–6) × 1018 and (2–3) × 1019 cm−3, e.g., for the SiO2/p+−Si(1019 cm−3) structures with the oxide thickness exceeding ∼3 nm. The electron density provided due to a resonant tunneling can reach rather high values (∼1012 cm−2 and more). Consequently, the quasi-Fermi level in the well is substantially shifted approaching that of the semiconductor bulk. However, a deformation of the band diagram due to electron charge in the quantum well in the regimes close to activation of a resonant transport is small.