Abstract: A method for forming a semiconductor device is disclosed in which a metal oxide gate dielectric layer is formed over a substrate. A gate electrode is then formed over the metal oxide layer thereby exposing a portion of the metal oxide layer. The exposed portion of the metal oxide gate dielectric layer is then chemically reduced to a metal or a metal hydride. The metal or metal hydride is then removed with a conventional wet etch or wet/dry etch combination. The metal oxide layer may include a metal element such as zirconium, tantalum, hafnium, titanium, or lanthanum and may further include an additional element such as silicon or nitrogen. Reducing the metal oxide layer may includes annealing the metal oxide gate dielectric layer in an ambient with an oxygen partial pressure that is less than a critical limit for oxygen desorption at a given temperature.

Abstract: In one embodiment, a metal layer (18) is formed over a gate dielectric layer (14, 16) on a semiconductor substrate. A masking layer (20) is patterned to mask a portion of the metal layer (18). An exposed portion of the metal layer (18) is nitrided to form a conductive nitride layer (24). The masking layer (20) is removed and the conductive nitride layer (24) is patterned to form a first gate electrode (23) having a first work function value, and the conductive layer (18) is patterned to form a second gate electrode (25) having a second work function value which is different from that of the first work function value.