A semiconductor device includes a substrate, an isolation feature over the substrate, a first device fin protruding from the substrate and through the isolation feature, and a second device fin protruding from the substrate and through the isolation feature. The semiconductor device also includes a dielectric fin disposed between the first and second device fins and a metal gate stack engaging the first and second device fins. The dielectric fin separates the metal gate stack into first and second segments and provides electrical isolation between the first and second segments. A portion of the isolation feature is directly under a bottom surface of the dielectric fin.