High dielectric constant materials as gate dielectrics (insulators)

摘要

A method and structure for a metal oxide semiconductor field effect transistor (MOSFET) includes patterning a gate stack (having a gate conductor layer and a gate dielectric) over a substrate and modifying the gate dielectric beneath the gate conductor, such that the gate dielectric has a central portion and modified dielectric regions adjacent the central portion. The modified dielectric regions have a lower dielectric constant than that of the gate dielectric and the central portion is shorter than the gate conductor.