Piezoelectric stack and method for manufacturing the piezoelectric stack

A method for manufacturing a piezoelectric stack, comprising:

• preparing a substrate;
• preparing a target composed of a perovskite-type oxide represented by a general formula ABO3, with A site containing K and Na, and B site containing Nb;
• depositing a bottom electrode film on the substrate;
• depositing a piezoelectric film composed of a perovskite-type oxide represented by a general formula ABO3, with A site containing K and Na, and B site containing Nb, on the bottom electrode film by a sputtering method using the target;
• depositing a top adhesive layer on the piezoelectric film;
• and
• depositing a top electrode film on the top adhesive layer,
• wherein in the preparation of the target, a first target, and a second target in which a ratio of a total number of K atoms and Na atoms contained per unit volume with respect to the number of Nb atoms contained per unit volume is smaller than that of the first target, are prepared, and
• in the deposition of the piezoelectric film, (a) applying equal power to the first target and the second target;
• and (b) applying a power to the second target that is greater than a power to the first target, performed in this order by using the first target and the second target, wherein (b) is started immediately before an end of deposition of the piezoelectric film.