A semiconductor device includes a semiconductor substrate, a first standard cell including a first active region and a second active region, and a power switching circuit including a first switching transistor electrically connected between a first interconnect and a second interconnect over the semiconductor substrate, and including a first buffer connected to a gate of the first switching transistor, the first buffer including a third active region and a fourth active region, and wherein the first buffer adjoins, in a plan view, the first standard cell in a first direction, wherein an arrangement of the first active region matches an arrangement of the third active region in a second direction different from the first direction, and wherein an arrangement of the second active region matches an arrangement of the fourth active region in the second direction.