Patent ID: 8044557

Claim:
A piezoelectric device comprising: a substrate; a lower electrode layer formed on the substrate; a piezoelectricity layer formed on the lower electrode layer; an upper electrode layer formed on the piezoelectricity layer; and and at least one of a lower adhesion layer formed between the piezoelectricity layer and the lower electrode layer so as to abut on the piezoelectricity layer and the lower electrode layer or an upper adhesion layer formed between the piezoelectricity layer and the upper electrode layer so as to abut on the piezoelectricity layer and the upper electrode layer; wherein each of the upper adhesion layer and the lower adhesion layer includes a first tungsten layer made of tungsten in which an α phase and a β phase coexist and a second tungsten layer made of α-phase tungsten, and the first tungsten layer is configured so as to abut on the piezoelectricity layer.