PIEZOELECTRIC DEVICE AND ITS MANUFACTURING METHOD

摘要

A piezoelectric device includes an upper contact layer (35) arranged between a piezoelectric layer (32) and an upper electrode layer (34) in such a manner that the upper contact layer (35) is in contact with the piezoelectric layer (32) and the upper electrode layer (34). The upper contact layer (35) is formed by a first tungsten layer (47) made of tungsten containing a mixture of a phase and ß phase and a second tungsten layer (48) made of tungsten of a phase. The first tungsten layer (47) is formed so as to be in contact with the piezoelectric layer (32). Thus, it is possible to obtain a piezoelectric device which has apreferable contact with both of the piezoelectric layer and the electrode layer and further reduce the reference point voltage fluctuation amount in a high-temperature operation, thereby improving the reliability.