Dielectric strength and interface-state behaviour of oxygen plasma-grown SiO2films annealed at high temperature†

Abstract

The behaviour of the interface-state density in plasma oxidized silicon dioxide on silicon MOS structures has been investigated as a function of annealing temperature and time for anneals in an ambient of dry nitrogen. It was found that the interface-state density decreases with increasing annealing time and temperature, saturating at a temperature of approximately 950^°C and a time of approximately one hour. In situ r.f. sputter-cleaning prior to oxidation produces dielectric films of uniformly high and reproducible dielectric strength of up to 10⁷ volts/em, in contrast to most chemical cleaning processes which typically yield lower dielectric strengths and greater variability.