Impact of Al incorporation in hafnia on interface states in (100)Si/HfAlxOy

Interface states in (100)Si/HfAlxOy entities were studied as affected by the oxide composition and post-growth thermal treatment. Incorporation of Al in hafnia is found to reduce the total (fast and slow) trap density compared to the case of elemental Al2O3 and HfO2, though the fast interface traps are only marginally influenced. As compared to the (100)Si/SiO2case, the excessive density of interface traps in the high-κ oxide/silicon structure is mainly caused by a significant contribution of some oxide-related defects.