In an embodiment, a device includes: a first semiconductor fin extending from a substrate; a second semiconductor fin extending from the substrate; a hybrid fin over the substrate, the second semiconductor fin disposed between the first semiconductor fin and the hybrid fin; a first isolation region between the first semiconductor fin and the second semiconductor fin; and a second isolation region between the second semiconductor fin and the hybrid fin, a top surface of the second isolation region disposed further from the substrate than a top surface of the first isolation region.