Work function adjustment with the implant of lanthanides

摘要

Semiconductor devices and fabrication methods are provided, in which fully silicided transistor gates are provided for MOS transistors. A lanthanide series metal is implanted into the gate electrode layer prior to silicidation and diffuses into the gate dielectric during an activation anneal. This process and resultant structure provides adjustment of the gate electrode work function, thereby tuning the threshold voltage of the resulting transistor.