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

We have investigated the interface states in HfO2∕SiO2∕Si(100) systems that were prepared by using the in situ pulsed laser deposition technique. X-ray photoelectron spectroscopy data revealed that when the HfO2 film thickness exceeds 11Å, the film composition undergoes a systematic change from Hf silicate to oxygen-deficient HfOx<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.