Metal-oxide-semiconductor field-effect-transistor substrate current during Fowler-Nordheim tunneling stress and silicon dioxide reliability

Abstract

The origin of the substrate current of a metal-oxide-semiconductor field-effect transistor when the gate oxide undergoes Fowler-Nordheim stress is investigated. It is also shown that anode hole injection current predicts the breakdown of silicon dioxide between 25 and 130 Å and 2.4 and 12 V. While the measured substrate current is entirely due to anode hole injection for oxides thicker than 55 Å, tunneling by valence-band electrons contributes to the substrate current in thinner oxides. Valence-band electron tunneling current is shown to increase with oxide stressing similar to low-voltage gate oxide leakage; apparently, both are enhanced by trap-assisted tunneling. For oxides of thickness between 25 and 130 Å, the theory of anode hole injection directly verified for oxides thicker than 55 Å is able to model silicon dioxide breakdown accurately.