Patent ID: 8390045

Claim:
A semiconductor device, comprising: a substrate; and a ferroelectric capacitor formed on the substrate, the ferroelectric capacitor including a lower electrode; a ferroelectric film formed on the lower electrode; and an upper electrode formed on the ferroelectric film, the upper electrode including a first layer formed of an oxide whose stoichiometric composition is expressed as chemical formula AOx 1 using a composition parameter x 1 and whose actual composition is expressed as chemical formula AOx 2 using a composition parameter x 2 ; a second layer formed on the first layer, the second layer being formed of an oxide whose stoichiometric composition is expressed as chemical formula BOy 1 using a composition parameter y 1 and whose actual composition is expressed as chemical formula BOy z using a composition parameter y 2 ; and a metal layer formed on the second layer, wherein the second layer is higher in ratio of oxidation than the first layer, the composition parameters x 1 , x 2 , y 1 , and y 2 satisfy y 2 /y 1 >x 2 /x 1 , and the second layer includes a first region of the stoichiometric composition formed at an interface with the metal layer and a second region between the first region and the first layer, and an oxygen concentration of the second layer is higher in the first region than in the second region.