Ultimate EOT scaling (< 5Å) using Hf-based high-κ gate dielectrics and impact on carrier mobility

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 high-κ gate dielectric. The remote IL scavenging shows advantages in carrier mobility and gate leakage current over conventional IL scaling schemes. Moreover, this method enables intrinsic EOT scaling without introducing additional charges and interface degradation. It is shown that the mobility degradation observed for a La-containing high-κ is not due to the La-induced dipole but due to the intrinsic IL scaling effect, whereas an Al-induced dipole brings about additional mobility degradation. This unique nature of the La-induced dipole in conjunction with the IL scaling enables aggressive EOT scaling toward the end of the road map. ©The Electrochemical Society.