Integrated circuit devices and methods of foming an integrated circuit device

Abstract

Integrated circuit devices and methods of forming the same are provided. The integrated circuit devices may include a substrate; an insulator on an upper surface of the substrate; a transistor between the substrate and the insulator, the transistor comprising: channel layers that are spaced apart from each other in a first direction that is perpendicular to the upper surface of the substrate; and a gate structure on the channel layers and the insulator, wherein a width of the insulator in a second direction that is parallel with the upper surface of the substrate is equal or substantially equal to a width of an uppermost one of the channel layers in the second direction.