A study of Hf vacancies at $Si:HfO2$ heterojunctions

In this work we have investigated the formation and migration of Hf vacancies in a $Si:HfO2$ heterostructure based on first principles calculations. Our calculations indicate that Hf vacancies tend to diffuse from bulk $HfO2$ to the $Si:HfO2$ interface and that it is energetically favorable for Si atoms to fill the interfacial Hf vacancies. These results provide a plausible mechanism of the formation of interfacial Hf silicates.