Theoretical study of the band offset at silicon-oxide/silicon interfaces with interfacial defects

Abstract

The role of interfacial defects in determining the band offset at silicon-oxide/silicon interfaces is studied using the first-principles band-offset evaluation method. The calculations are based on the cristobalite Si(100) interface model. The results show that interfacial SiOH bonds greatly enhance the valence band offset while interfacial SiH bonds slightly enhance the offset. The changes in the band offsets can be explained by measuring the changes in the interfacial dipoles. These results indicate that interfacial SiOH bonds can cause gate oxide deterioration in a metal-oxide-semiconductor device. It was also found that the experimentally reported hydrogen annealing effects on the barrier height cannot be explained only by termination of interfacial Si dangling bonds by H atoms or only by the creation of interfacial OH defects.