Annealing of ultrathin silicon dioxide layers plasma oxidized in ultrahigh vacuum

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 1011 eVy1 cmy2 in the mid-gap can be reached without any annealing. The oxide charge, however, is then quite high. By using post metallization annealing in 3008C or post oxidation UHV annealing in 7508C the surface state densities can slightly be decreased. The oxide charge can be totally removed in 7508C. Neither of these annealings decrease the oxide thickness. q1999 Elsevier Science B.V. All rights reserved.