US Patent 7605007 Semiconductor device and method of manufacturing the same

An upper electrode film includes a first conductive oxidation layer made of an oxide expressed by a chemical formula M1Ox2, a second conductive oxidation layer made of an oxide expressed by a chemical formula M2Oy2 and a third conductive oxidation layer. Here, the second conductive oxidation layer is formed to have a degree of oxidation higher than the first conductive oxidation layer and the third conductive oxidation layer, and among the composition parameters x1, x2, y1, y2, z1 and z2, there are the following relations,y2/y1>x2/x1, y2/y1>z2/z1, and z2/z1≧x2/x1.