abstract |
A method of fabricating a plurality of field effect transistors with different threshold voltages, including forming a cover layer on a channel region in a first subset, forming a first sacrificial layer on two or more channel regions in a second subset, forming a second sacrificial layer on one of the two or more channel regions in the second subset, removing the cover layer from the channel region in the first subset, forming a first dummy dielectric layer on the channel region in the first subset, and forming a second dummy dielectric layer on the first dummy dielectric layer and the first sacrificial layer on the channel region in the second subset. |