Patent ID: 7605007

Claim:
A semiconductor device, comprising: a semiconductor substrate; and a capacitor structure formed over said semiconductor substrate and structured by the capacitor film being sandwiched between an upper electrode and a lower electrode, wherein said upper electrode, comprising: a first layer made of an oxide, of which stoichiometric composition is expressed by a chemical formula M 1 O x1 using a composition parameter x 1 , and of which practical composition is expressed by a chemical formula M 1 O x2 using a composition parameter x 2 ; a second layer made of an oxide formed on said first layer, and its stoichiometric composition is expressed by a chemical formula M 2 O y1 using a composition parameter y 1 , and its practical composition is expressed by a chemical formula M 2 O y2 using a composition parameter y 2 ; and a third layer made of an oxide formed on said second layer, and its stoichiometric composition is expressed by a chemical formula M 3 O z1 using a composition parameter z 1 , and its practical composition is expressed by a chemical formula M 3 O z2 using a composition parameter z 2 , where the symbols M 1 , M 2 and M 3 are respectively expressed as one or plural metal elements, wherein said second layer has a degree of oxidation higher than said first layer and said third layer; and wherein said composition parameters x 1 , x 2 , y 1 , y 2 , z 1 and z 2 have the following relations therebetween, y 2 /y 1 >x 2 /x 1 , y 2 /y 1 >z 2 /z 1 , and z 2 /z 1 ≧x 2 /x 1 .