A semiconductor device includes a gate insulating film formed on a semiconductor substrate, a first gate electrode formed on the gate insulating film, a second gate electrode formed on the gate insulating film between the first gate electrode and a contact plug, a first silicon oxide film formed above the substrate between the first and second gate electrodes, a first silicon nitride film formed along the substrate and a side surface of the second gate electrode between the contact plug and the second gate electrode, a second silicon oxide film formed on the first silicon oxide film, the first gate electrode and the second gate electrode, the second silicon oxide film including an upper surface having a height greater than the height of a first upper surface of the first gate electrode relative to the substrate, and a second silicon nitride film formed on the second silicon oxide film.