Two components of tunneling current in metal-oxide-semiconductor structures

Two distinct components of tunneling current in silicon metal-oxide-semiconductor structures are identified. In addition to the electron tunneling from the conduction band of the semiconductor, there is a second component interpreted as electron tunneling from the valence band. This is manifested as hole current in the silicon substrate. The ratio of valence-band to conduction-band tunneling currents is about 10−3, and increases slightly with the oxide field. This ratio is independent of oxide thickness, temperature, and gate-electrode material.