Density functional calculations on atomic and electronic structures of amorphous HfO2/Si(001) interface

The interface properties of amorphous hafnium dioxide (a-HfO2) in contact with silicon have been investigated by using the projector augmented wave method within the generalized gradient approximation. The a-HfO2 model structure of the interface is generated by ab initio molecular dynamics simulations in a melt-and-quench scheme. Calculations indicate that the simulated a-HfO2 essentially shows the characteristics of the experimental a-HfO2 structure. The results on a-HfO2/Si interface suggest that atomic coordination of interface Si atoms would significantly affect the interface electronic properties, e.g., the Hf-Si bond formed at the interface could result in metallic behavior. With band lineup of the core level, the valence band offset of a-HfO2/Si interface is determined to be 2.62 +/- 0.35 eV, in good agreement with recent experimental data.