In some embodiments, a semiconductor device includes a first active pattern extended in a first horizontal direction on a substrate, a second active pattern extended in the first horizontal direction on the substrate, a first bottom gate electrode extended in a second horizontal direction on the first active pattern, a first upper gate electrode extended in the second horizontal direction on the first bottom gate electrode, a second bottom gate electrode extended in the second horizontal direction on the second active pattern, a second upper gate electrode extended in the second horizontal direction on the second bottom gate electrode, and a first gate cut comprising a first portion isolating the first bottom gate electrode from the second bottom gate electrode and a second portion isolating the first upper gate electrode from the second upper gate electrode. A width of the second portion exceeds a width of the first portion.