A novel split-gate MOSFET design realized by a fully silicided gate process for the improvement of transconductance and output resistance

Abstract

Work function tuning of nickel silicide (NiSi) gates was utilized to fabricate a novel split-gate MOSFET with improved device performance. The MOSFET with a NiSi split gate has been achieved by implanting antimony into the polysilicon gate from the drain side with a tilt angle, followed by a full nickel-silicidation process. The laterally nonuniform antimony implantation causes the NiSi gate work function to vary from the source side to the drain side due to the dopant segregation effect. Improved current drive and output resistance are observed in the MOSFET with such a NiSi split gate. Metal gate advantages and NiSi process simplicity were also realized in the split-gate process, and gate oxide quality did not degrade due to the low temperature process. This split-gate design is expected to be applicable in the nanoscale regime by optimizing process conditions.