The present application discloses a semiconductor device. The semiconductor device includes a substrate comprising an array area and a peripheral area adjacent to the array area; word line structures positioned in the array area; a word line hard mask layer positioned on the array area; a word line protection layer positioned on the word line hard mask layer; a gate electrode layer positioned on the peripheral area and separated from the word line hard mask layer and the word line protection layer; a peripheral protection layer positioned on the to gate electrode layer; and a first hard mask layer positioned over the array area and the peripheral area. A horizontal distance between the word line protection layer and the gate electrode layer is greater than or equal to three times of a thickness of the first hard mask layer.