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 silicate interfaces. Owing to the d character of zirconium silicate conduction bands, the band gap and band offset are shown to decrease as the zirconium concentration is increased. Since the valence band character of silicates remains unchanged relative to SiO2, the conduction band offset alone decreases, leading to increasingly asymmetric band offsets at higher zirconium concentrations. The use of charge transfer dipoles at the interface is investigated as a possible remedy to restore the band offset symmetry by shifting the silicate bands relative to the silicon bands.