High-k metal-gate PMOS FinFET threshold voltage tuning with aluminum implantation

Abstract
In this work, we report the use of Aluminum ion implantation to modulate the threshold voltage for Hf-based high-k /TiN metal gate PMOS FinFETs on SOI. A positive 170mV VFB shift with 0.8Å reduction in CETinv was achieved by implanting Aluminum at shallow tilt angle into TiN on the sidewalls of FinFETs. The Al was thermally driven during the SD activation anneal to form dipoles in the high-k dielectric to tune the PMOS Vt, resulting in 8% performance improvement in PMOS Ion/Ioff, without degrading short channel effects. These results demonstrate key progress towards realizing multi-Vt FinFET device architectures for 20nm node and beyond. Remote interfacial layer scavenging of oxygen induced by the metal gate dopants has an added advantage of improving the CET, without impacting short channel behavior.