SEMICONDUCTOR DEVICE

A semiconductor device includes a substrate including first and second regions; a first active fin extending in a first direction on the first region; a second active fin extending in the first direction on the second region; an isolation pattern on the substrate between the first and second regions; a first gate structure on the first active fin, extending in a second direction perpendicular to the first direction, and onto an upper surface of the isolation pattern; and a second gate structure on the second active fin, extending in the second direction, and onto the upper surface of the isolation pattern, wherein the first gate structure includes a first portion having a first width and a second portion having a second width that is less than the first width, and the second gate structure includes a third portion having the first width and a fourth portion having the second width.