US Patent 7531399 Semiconductor devices and methods with bilayer dielectrics

A semiconductor device is disclosed that includes: a substrate; a first high-k dielectric layer; a second high-k dielectric layer formed of a different high-k material; and a metal gate. In another form, a method of forming a semiconductor device is disclosed that includes: providing a substrate; forming a first high-k dielectric layer above the substrate; forming a second dielectric layer of a different high-k material above the first dielectric layer; and forming a gate structure above the second dielectric layer. In yet another form, a method of forming a semiconductor device is disclosed that includes: providing a substrate; forming an interfacial layer above the substrate; forming a first high-k dielectric layer above the interfacial layer; performing a nitridation technique; performing an anneal; forming a second high-k dielectric layer of a different high-k material above the first dielectric layer; and forming a metal gate structure above the second dielectric layer.