SEMICONDUCTOR DEVICE HAVING DEVICE ISOLATION LAYERS

A semiconductor device includes device isolation layers extending in a first horizontal direction and spaced apart from each other in a second horizontal direction intersecting the first horizontal direction, active regions between the device isolation layers and spaced apart from each other in the first horizontal direction, insulating structures between the active regions, and a gate structure extending in a third horizontal direction between the first horizontal direction and the second horizontal direction and intersecting the active regions, wherein two side surfaces of each active region adjacent to each other define an acute angle, and wherein at least a portion of at least one of the insulating structures is between a corresponding pair of the active regions and between a corresponding pair of the device isolation layers and overlaps the corresponding pair of the active regions in the first horizontal direction.