Fabrication of midgap metal gates compatible with ultrathin dielectrics

A process has been described which can produce a midgap tungsten gate compatible with the current and future complementary metal–oxide–semiconductor technology. The tungsten was deposited directly onto a 3.0 nm SiO2 gate dielectric without measurable degradation of any of its electrical properties. The tungsten deposition process yields no reactive or corrosive by-products that affect the gate dielectric integrity. The tungsten film is found to be pure within the limits of several analytical techniques and the resistivity of the tungsten films was found to be within a factor of 2 of the bulk value.