Patent ID: 7291960

Claim:
A piezoelectric device comprising: a substrate; a first conductive layer formed over the substrate, the first conductive layer including a conductive oxide layer formed of a (001) preferentially oriented lanthanum nickelate, and the lanthanum nickelate having oxygen deficiency, the first conductive layer including at least one buffer layer formed of a (001) preferentially oriented lanthanum-based layered perovskite compound, and the lanthanum-based layered perovskite compound including at least one of La 2 NiO 4 , La 3 Ni 2 O 7 , La 4 Ni 3 O 10 , La 2 CuO 4 , and a solid solution of at least two of La 2 NiO 4 , La 3 Ni 2 O 7 , La 4 Ni 3 O 10 , and La 2 CuO 4 ; a piezoelectric layer formed over the first conductive layer and including a piezoelectric having a perovskite structure; and a second conductive layer electrically connected with the piezoelectric layer.