PIEZOELECTRIC DEVICE AND ITS MANUFACTURING METHOD

摘要

Upper adhesion layer 35 formed between piezoelectricity layer 32 and upper electrode layer 34 so as to abut on piezoelectricity layer 32 and upper electrode layer 34 is included. Upper adhesion layer 35 includes first tungsten layer 47 made of tungsten in which an ± phase and a ² phase coexist and second tungsten layer 48 made of ±-phase tungsten. First tungsten layer 47 is configured so as to abut on piezoelectricity layer 32. It is possible to obtain a piezoelectric device which is capable of improving the adhesion property of both the piezoelectricity layer and the electrode layer and reducing a basic point voltage fluctuation at the time of high-temperature operation so as to improve reliability.