Role of oxygen vacancy in HfO₂/SiO₂/Si(100) interfaces

We have investigated the interface states in Hf O2 Si O2 Si (100) systems that were prepared by using the in situ pulsed laser deposition technique. X-ray photoelectron spectroscopy data revealed that when the Hf O2 film thickness exceeds 11 Å, the film composition undergoes a systematic change from Hf silicate to oxygen-deficient Hf Ox<2. Furthermore, we determined that the evolution of the interface states clearly depends on the oxygen condition applied during the film growth and that the oxygen vacancy is an important parameter for Hf silicate formation.