Understanding mobility mechanisms in extremely scaled HfO₂ (EOT 0.42 nm) using remote interfacial layer scavenging technique and V _t-tuning dipoles with gate-first process

Abstract

We demonstrate a novel "remote interfacial layer (IL) scavenging" technique yielding a record-setting equivalent oxide thickness (EOT) of 0.42 nm using a HfO2-based MOSFET high-κ gate dielectric. Intrinsic effects of IL scaling on carrier mobility are clarified using this method. We reveal that the mobility degradation observed for La-containing high-κ is not due to the La dipole but due to the intrinsic IL scaling effect, whereas an Al dipole brings about additional mobility degradation. This unique nature of the La dipole enables aggressive EOT scaling in conjunction with IL scaling for the 16 nm technology node without extrinsic mobility degradation. © 2009 IEEE.