In accordance with the invention, there are CMOS devices and semiconductor devices and methods of fabricating them. The CMOS device can include a substrate including a first active region and a second active region and a first transistor device over the first active region, wherein the first transistor device includes a high-K layer over the first active region, a first dielectric capping layer on the high-K layer, and a first metal gate layer over the first dielectric capping layer. The CMOS device can also include a second transistor device over the second active region, wherein the second transistor device includes a high-K layer over the second active region, a second dielectric capping layer on the second high-K layer, and a second metal gate layer over the second dielectric capping layer.