Semiconductor device and method for manufacturing the same

1. 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.

2. The semiconductor device according to claim 1 , further comprising

a conducting adhesion layer formed between the insulation layer and the oxygen barrier film, for improving the crystallinity of the oxygen barrier film and improving the adhesion between the oxygen barrier film and the insulation layer.

3. The semiconductor device according to claim 2 , wherein

the adhesion layer is formed of TiN, Ti, Ti alloy, Al, Al alloy, Pt, Pt alloy, Ir, Ir alloy, Re, Re alloy, Ru, Ru alloy, Pd, Pd alloy, Os, Os alloy, Rh, Rh alloy, platinum oxide, iridium oxide, ruthenium oxide or palladium oxide.

4. 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; and

a conducting oxygen barrier film formed between the conductor plug and the first conduction film, for preventing the oxidation of the surfaces of the conductor plug, the oxygen barrier film being formed of TiAIN, TiAION, TaAIN or TaAION,

wherein

the capacitor dielectric film contains a first element of Pb or Bi,

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 an 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.

5. 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 electrode is remote from the interface between the lower electrode and the oxygen barrier film.