Activity of piezoelectric material dimension and electrical properties can be changed with an applied stress. These variations are translated to a change in capacitance of the structure. Use of capacitance-voltage measurements for the extraction of double piezoelectric thin film material deposited at the two faces of a flexible steel sheet is described. Piezoelectric thin film materials are deposited using RF sputtering techniques. Gamry analyzer references 3000 is used to collect the capacitance-voltage measurements from both layers. A developed algorithm extracts directly the piezoelectric coefficients knowing film thickness, applied voltage, and capacitance ratio. The capacitance ratio is the ratio between the capacitances of the film when the applied field in antiparallel and parallel to the poling field direction, respectively. Piezoelectric bulk ceramic is used for calibration and validation by comparing the result with the reported values from literature. Extracted values using the current approach match well values extracted by existing methods.

A sensor includes a plurality of piezoresistive elements and a plurality of electrical connection terminals. The plurality of piezoresistive elements are fabricated on a first side of a substrate. A second side of the substrate is configured to be coupled to an object where a physical disturbance is to be detected. A plurality of electrical connection terminals are coupled to the first side of the substrate.

A piezoelectric element 10 includes a lower electrode, constituted of a Pt/Ti laminated film, a PLT seed layer, formed on the lower electrode, a PZT piezoelectric film, formed on the PLT seed layer, and an upper electrode, formed on the PZT piezoelectric film. A curve Q1 is a curve drawn such as to pass through a plurality of plotted points, each expressing a PLT (100) peak intensity with respect to a Pt (111) peak intensity according to a substrate setting temperature during forming of the Pt/Ti laminated film. A relationship of the PLT (100) peak intensity with respect to the Pt (111) peak intensity is within a range in the curve Q1 until the PLT (100) peak intensity decreases by 5% from a peak point P, at which the PLT (100) peak intensity is the maximum, and a (100) orientation rate of PLT constituting the seed layer is not less than 85%.

A piezoelectric element 10 includes a lower electrode, constituted of a Pt/Ti laminated film, a PLT seed layer, formed on the lower electrode, a PZT piezoelectric film, formed on the PLT seed layer, and an upper electrode, formed on the PZT piezoelectric film. A curve Q1 is a curve drawn such as to pass through a plurality of plotted points, each expressing a PLT (100) peak intensity with respect to a Pt (111) peak intensity according to a substrate setting temperature during forming of the Pt/Ti laminated film. A relationship of the PLT (100) peak intensity with respect to the Pt (111) peak intensity is within a range in the curve Q1 until the PLT (100) peak intensity decreases by 5% from a peak point P, at which the PLT (100) peak intensity is the maximum, and a (100) orientation rate of PLT constituting the seed layer is not less than 85%.

There is provided a piezoelectric stack, including: a substrate; an oxide film on the substrate, containing zinc and oxygen as main elements; an electrode film on the oxide film; and a piezoelectric film on the electrode film, being an alkali niobium oxide film containing potassium, sodium, niobium, and oxygen and having a perovskite structure.

There is provided a piezoelectric stack, including: a substrate; an oxide film on the substrate, containing zinc and oxygen as main elements; an electrode film on the oxide film; and a piezoelectric film on the electrode film, being an alkali niobium oxide film containing potassium, sodium, niobium, and oxygen and having a perovskite structure.

A sensor apparatus includes a first of a plurality of layers having a top layer, a bottom layer, and at least one intermediate layer having an electrical conductor layer, each of the top layer, the bottom layer, and the at least one intermediate layer is disposed in direct contact with a respective adjacent layer. A second of the plurality of layers is disposed in direct contact with the first plurality of layers such that the bottom layer of the second plurality of layers is disposed in direct contact with the top layer of the first plurality of layers. The first and second plurality of layers are productive of a piezoelectric voltage absent of an external current producing device and in response to being deformed, and are productive of a change in capacitance in response to being deformed.

A sensor apparatus includes a first of a plurality of layers having a top layer, a bottom layer, and at least one intermediate layer having an electrical conductor layer, each of the top layer, the bottom layer, and the at least one intermediate layer is disposed in direct contact with a respective adjacent layer. A second of the plurality of layers is disposed in direct contact with the first plurality of layers such that the bottom layer of the second plurality of layers is disposed in direct contact with the top layer of the first plurality of layers. The first and second plurality of layers are productive of a piezoelectric voltage absent of an external current producing device and in response to being deformed, and are productive of a change in capacitance in response to being deformed.

Disclosed is a method for manufacturing a piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin film, comprising: forming a stress control layer comprised of a Group III nitride on a silicon substrate by chemical vapor deposition (CVD); and depositing a piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin film on the stress control layer, the thin film being deposited by PVD at 0.3 Tm (Tm is melting temperature of a piezoelectric thin film material) or higher. Further, a method for manufacturing a device in conjunction with piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin films is provided.

A piezoelectric actuator includes a vibration portion, a support portion that is integrally configured with the vibration portion and supports the vibration portion, and a piezoelectric element that is disposed on the vibration portion. The piezoelectric element includes a piezoelectric film including columnar crystal grains extending in a thickness direction. When a thickness of the piezoelectric film is referred to as T [μm] and an average diameter of the crystal grains in the width direction is referred to as D [μm], T/D is within a range of 10 to 100. The thickness T of the piezoelectric film is larger than or equal to 2 μm. A standard deviation of diameters of the crystal grains in the width direction is less than or equal to 1.8 μm.