A semiconductor device may include a substrate including an active pattern delimited by a device isolation pattern, a gate electrode crossing the active pattern, a first impurity region and a second impurity region in the active pattern on both sides of the gate electrode, a bit line crossing the gate electrode, a first contact electrically connecting the first impurity region with the bit line, and a first nitride pattern on a lower side surface of the first contact. A width of the first contact measured perpendicular to an extending direction of the bit line may be substantially equal to that of the bit line.