Patent ID: 6853021

Claim:
An oriented ferroelectric thin-film device comprising: a substrate; a polycrystalline conductive thin-film disposed on the substrate; and a ferroelectric thin-film disposed on the polycrystalline conductive thin-film, the ferroelectric thin-film comprising a Pb-containing perovskite oxide expressed by the formula ABO 3 , wherein A is one of Pb and a mixture of Pb and La, and B is at least one element selected from the group consisting of Ti, Zr, Mg and Nb, and the ferroelectric thin-film including: a first ferroelectric sub-layer disposed on a surface of the polycrystalline conductive thin-film; and a second ferroelectric sub-layer disposed on a surface of the first ferroelectric sub-layer, wherein the first ferroelectric sub-layer has a composition which changes from the surface of the polycrystalline conductive thin-film towards the second ferroelectric sub-layer, the second ferroelectric sub-layer has a constant composition, and the first and second ferroelectric sub-layers have substantially the same composition at the boundary therebetween.