The description relates to a fin field effect transistor (FinFET). An exemplary structure for a FinFET includes a fin having a first height above a first surface of a substrate, where a portion of the fin has first tapered sidewalls, and the fin has a top surface. The FinFET further includes an insulation region over a portion of the first surface of the substrate, where a top of the insulation region defines a second surface. The FinFET further includes a gate dielectric over the first tapered sidewalls and the top surface. The FinFET further includes a conductive gate strip over the gate dielectric, where the conductive gate strip has second tapered sidewalls along a longitudinal direction perpendicular to the first height, and a first width between the second tapered sidewalls in the longitudinal direction is greater at a location nearest to the substrate than a second width at a location farthest from the substrate.