Changhwan Choi

Understanding mobility mechanisms in extremely scaled HfO 2 (EOT 0.42 nm) using remote interfacial layer scavenging technique and V t -tuning dipoles with gate-first process

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-к 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-к 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.

High-

Schottky source/drain (S/D) MOSFETs hold the promise for low series resistance and extremely abrupt junctions, providing a path for device scaling in conjunction with a low Schottky barrier height (SBH). A S/D junction SBH approaching zero is also needed to achieve a competitive current drive. In this letter, we demonstrate a CMOS process flow that accomplishes a reduction of the S/D SBH for nFET and pFET simultaneously using implants into a common NiPt silicide, followed by a low-temperature anneal (500°C-600°C). These devices have high-κ/metal gate and fully depleted extremely thin SOI with sub-30-nm gate length.