Atomic layer deposited (ALD) Hf-based dielectrics have been studied to understand scaling, electron mobility, and threshold voltage stability issues in transistor devices, ALD HfO2 formed from TEMAHf and O3 was found to reach a scaling limit near Tphys=1.2 nm. Knowledge of this limit is important because mobility improvements are observed as HfO 2 is scaled to 2.0 nm and below. Concurrent with mobility improvement, a reduction in transient charging is manifested as improved V TH and Id stability during constant voltage stress. HfO2 attributes include the following: EOT=1.0 nm, >100× Jg reduction vs. SiO2/PolySi, high field mobility of 82% universal SiO2 and ∼20 mV of ΔVTH after 1000s stress at 1.8V. Similar results can be obtained for (HfO2) x(SiO2)1-x alloys. These results suggest that high-k dielectrics can be competitive with the current gate dielectric material SiON. copyright The Electrochemical Society.