Piezoelectric thin film element including upper and lower electrodes, and an actuator and a sensor fabricated by using the same

摘要

A piezoelectric thin film element includes a substrate, a lower electrode, a piezoelectric thin film, and an upper electrode. The lower electrode, the piezoelectric thin film and the upper electrode are formed on the substrate. The piezoelectric thin film includes a polycrystal thin film including crystal grains, an alkali niobium oxide based perovskite structure represented by a general formula: (K_1-xNa_x)NbO₃ (0.4x0.7), a film thickness of not less than 1 μm and not more than 10 μm, a columnar structure configured by the crystal grains, a majority of the crystal grains including a shape in a cross-section direction thereof longer than in a plane direction of the substrate, and an average crystal grain size of not less than 0.1 μm and not more than 1.0 μm in the plane direction of the substrate.