Performance of $HfO2∕TiN$ gate stacks with in situ grown and $O3$ chemical interfacial oxide layers

Electrical properties of the gate stacks with atomic-layer-deposited $HfO2$ dielectric on either a HF-last cleaned Si substrate or chemical oxide grown by an $O3∕de-ionized$ water clean have been evaluated. The properties of the oxide layers formed at the interface between the high-$k$ dielectric and the substrate in both types of gate stacks are similar as they exhibit identical equivalent oxide thickness and comparable gate leakage current values. However, the gate stack formed on the HF-last cleaned surface shows higher intrinsic mobility and transient charge trapping, which may be explained by the oxygen deficiency model.