Patent ID: 7397090

Claim:
A semiconductor device having a first well of a first conductivity type and a second well of a second conductivity type, the semiconductor device comprising: a gate dielectric layer extending over at least a portion of the first well and the second well; a first gate electrode disposed on the gate dielectric layer and extending over the first well, the first gate electrode comprising a multi-layer stack, comprising: (i) a first thin metal/metal nitride layer disposed on the gate dielectric layer; (ii) a second thin metal/metal nitride layer disposed on the first thin metal/metal nitride layer; (iii) a third thin metal/metal nitride layer disposed on the second thin metal/metal nitride layer; and (iv) a first thick metal/metal nitride layer disposed on the third thin metal/metal nitride layer a first source electrode and a first drain electrode formed in the first well adjacent to the first gate electrode; a second gate electrode disposed on the gate dielectric layer and extending over the second well, the second gate electrode comprising a portion of the first thick metal/metal nitride layer; and a second source electrode and a second drain electrode formed in the second well adjacent to the second gate electrode, wherein the first, second, and third thin metal/metal nitride layers are of an amorphous form and the first thick metal/metal nitride layer is of a polycrystalline form.