WORK FUNCTION ADJUSTMENT WITH THE IMPLANT OF LANTHANIDES

摘要

Semiconductor devices and fabrication methods are provided, in which fully silicided gates are provided. 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.

主权项

1. A method of forming a transistor, comprising:
forming a gate dielectric over a semiconductor body, wherein the gate dielectric comprises a material in a top portion thereof that does not extend to an interface between the gate dielectric and the semiconductor body, wherein the material is selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium; and forming a silicon gate electrode over the gate dielectric.