Integrated circuit device

An integrated circuit device includes: a semiconductor-on-insulator (SOI) substrate layer including a base substrate layer, an insulating substrate layer, and a capping substrate layer; a semiconductor substrate layer; a plurality of first fin-type active regions and a plurality of second fin-type active regions, the plurality of first fin-type active regions and the plurality of second fin-type active regions being defined by a plurality of trenches and respectively extending in a first horizontal direction over the SOI substrate layer and the semiconductor substrate layer; a plurality of nanosheet stacked structures including a plurality of nanosheets extending parallel to each other and spaced apart from upper surfaces of the plurality of first fin-type active regions and the plurality of second fin-type active regions; a plurality of first source/drain regions extending into the SOI substrate layer; and a plurality of second source/drain regions extending into the semiconductor substrate layer. Lower surf