Patent ID: 8373212

Claim:
A semiconductor device comprising: a transistor formed over a semiconductor substrate; an insulation layer covering the semiconductor substrate and the transistor; a conductor plug buried in the insulation layer and electrically coupled to the transistor; a capacitor formed over the semiconductor substrate and the conductor plug and including a lower electrode formed of a first conduction film, and a second conduction film formed directly on the first conduction film, a capacitor dielectric film formed over the lower electrode, and an upper electrode formed over the capacitor dielectric film, the capacitor dielectric film containing a first element of Pb or Bi; and a conducting oxygen barrier film formed between the conductor plug and the first conduction film, for preventing an oxidation of the surfaces of the conductor plug, the oxygen barrier film being formed of TiAIN, TiAION, TaAIN or TaAION, wherein the lower electrode prevents the diffusion of the first element at an interface between the first conduction film and the second conduction film, the lower electrode further comprises a third conduction film formed of Pt, a Pt alloy, Pd or a Pd alloy formed directly on the second conduction film, the first conduction film is an iridium oxide film or a ruthenium oxide film, the second conduction film is an iridium oxide film or a ruthenium oxide film, a concentration of the first element at the interface between the first conduction film and the second conduction film is higher than a concentration of the first element at an interface between the first conduction film and the oxygen barrier film, and the concentration peak of the first element in the lower electrodes positions in the interface between the first conduction film and the second conduction film.