First principles investigation of scaling trends of zirconium silicate interface band offsets

First principles density functional theory calculations are carried out to investigate the scaling trends of band offsets at model silicon/zirconium s ilicate interfaces. Owing to the d character of zirconium silicate conducti on bands, the band gap and band offset are shown to decrease as the zirconi um concentration is increased. Since the valence band character of silicate s remains unchanged relative to SiO2, the conduction band offset alone decr eases, leading to increasingly asymmetric band offsets at higher zirconium concentrations. The use of charge transfer dipoles at the interface is inve stigated as a possible remedy to restore the band offset symmetry by shifti ng the silicate bands relative to the silicon bands. (C) 2001 American Inst itute of Physics.