A capacitor having an equivalent thickness of 3.0 nm or less, with a sufficient static capacitance and less leakage current in a reduced size, constituted by stacking an interfacial film 21 having a physical thickness of 2.5 nm or more for suppressing tunnel leakage current and a high dielectric film 22 comprising tantalum pentaoxide on lower electrode 19, 20 comprising rugged polycrystal silicon film, the interfacial film 21 comprising a nitride film formed by an LPCVD method, for example, from Al2O3, a mixed phase of Al2O3 and SiO2, ZrSiO4, HfSiO4, a mixed phase of Y2O3 and SiO2, and a mixed phase of La2O3 and SiO2.