An integrated circuit includes a substrate, a first transistor, and a second transistor. The first transistor has a first gate dielectric portion located between a first gate electrode and the substrate. The first gate dielectric portion includes a first high-permittivity dielectric material and/or a second high-permittivity dielectric material. The first gate dielectric portion has a first equivalent silicon oxide thickness. The second transistor has a second gate dielectric portion located between a second gate electrode and the substrate. The second gate dielectric portion includes the first high-permittivity dielectric material and/or the second high-permittivity dielectric material. The second gate dielectric portion has a second equivalent silicon oxide thickness. The second equivalent silicon oxide thickness may be different than the first equivalent silicon oxide thickness.