| CPC H02N 2/028 (2013.01) [H10N 30/50 (2023.02); H10N 30/704 (2024.05); H10N 30/8548 (2023.02); H10N 30/8554 (2023.02); H10N 30/878 (2023.02); G02B 26/0858 (2013.01)] | 8 Claims |
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1. A piezoelectric actuator comprising:
a substrate; and
a drive structure formed on the substrate,
wherein the drive structure includes a piezoelectric thin film, and an average grain size of the piezoelectric thin film is 450 nm or greater and 600 nm or less,
wherein the piezoelectric thin film includes a first piezoelectric thin film and a second piezoelectric thin film, and a lower electrode and an intermediate electrode provide drive voltage to the first piezoelectric thin film and the second piezoelectric thin film,
wherein the lower electrode includes a plurality of layers, a lowermost layer and an uppermost layer of the lower electrode among the plurality of layers of the lower electrode are formed of a conductive oxide film, an average grain size of the conductive oxide film of the uppermost layer of the lower electrode is 30 nm or greater and 35 nm or less, and the first piezoelectric thin film is formed on the uppermost layer of the lower electrode, and
wherein the intermediate electrode includes a plurality of layers, a lowermost layer and an uppermost layer of the intermediate electrode among the plurality of layers of the intermediate electrode are formed of a conductive oxide film, an average grain size of the conductive oxide film of the uppermost layer of the intermediate electrode is 30 nm or greater and 35 nm or less, the second piezoelectric thin film is formed on the uppermost layer of the intermediate electrode, and the lowermost layer of the intermediate electrode is formed on the first piezoelectric thin film.
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