The formation and migration of Hf vacancies in a Si:HfO2 heterostructure were investigated, based upon first-principles calculations. The calculations indicated that Hf vacancies tended to diffuse from bulk HfO2 to the Si:HfO2 interface and that it was energetically favorable for Si atoms to fill the interfacial Hf vacancies. These results provided a plausible mechanism of the formation of interfacial Hf silicates.

A Study of Hf Vacancies at Si:HfO2 Heterojunctions. C.Tang, R.Ramprasad: Applied Physics Letters, 2008, 92[15], 152911