Annealing of ultrathin silicon dioxide layers plasma oxidized in ultrahigh vacuum

Abstract

Ultrathin silicon dioxide layers have been fabricated by the room temperature plasma oxidation of silicon in ultrahigh vacuum. Silicon–silicon dioxide interface state densities of 10 11 eV −1 cm −2 in the mid-gap can be reached without any annealing. The oxide charge, however, is then quite high. By using post metallization annealing in 300°C or post oxidation UHV annealing in 750°C the surface state densities can slightly be decreased. The oxide charge can be totally removed in 750°C. Neither of these annealings decrease the oxide thickness.