Abstract: There is provided a piezoelectric film-attached substrate, including a piezoelectric film having a specific thickness, wherein a reflection spectrum shows a relation between a light obtained in such a way that the surface of the piezoelectric film is irradiated with an irradiation light having a specific wavelength and the irradiation light is reflected on the surface of the piezoelectric film, and a light obtained in such a way that the irradiation light is transmitted through the piezoelectric film and is reflected on the surface of the lower electrode, which is the reflection spectrum at least at one point on a center part and an outer peripheral part of the piezoelectric film, and such a reflection spectrum has at least one of the maximum value and the minimum value respectively, wherein the reflectance at least in one maximum value is 0.4 or more.

Abstract: There is provided a piezoelectric thin film element, comprising: a substrate 1; and a piezoelectric thin film 3 having an alkali niobium oxide-based perovskite structure represented by a composition formula (K1-xNax)yNbO3 provided on the substrate 1, wherein a carbon concentration of the piezoelectric thin film 3 is 2×1019/cm3 or less, or a hydrogen concentration of the piezoelectric thin film 3 is 4×1019/cm3 or less.

Abstract: To provide a piezoelectric film element, including: a substrate; and a piezoelectric film having an alkali niobium oxide-based perovskite structure represented by a composition formula (K1-xNax)yNbO3 (0<x<1) provided on the substrate, wherein the alkali niobium oxide-based composition falls within a range of 0.40?x?0.70 and 0.77?y?0.90, and further a ratio of an out-of-plane lattice constant (c) to an in-plane lattice constant (a) of the (K1-xNax)yNbO3 film is set in a range of 0.985?c/a?1.008.

Abstract: A manufacturing method of a piezoelectric film element includes forming a piezoelectric film including a lead-free alkali niobate based compound having a perovskite structure represented by a compositional formula of (K1-xNax)NbO3 on a substrate, and dry-etching the piezoelectric film by using a low-pressure plasma including a fluorine system reactive gas.

Abstract: There is provided a piezoelectric film having an alkali niobate-based perovskite structure expressed by a general formula (NaxKyLiz)NbO3(0?x?1, 0?y?1, 0?z?0.2, x+y+z=1), wherein the alkali niobate has a crystal structure of a pseudo-cubic crystal, a tetragonal crystal, an orthorhombic crystal, a monoclinic crystal, a rhombohedral crystal, or has a crystal structure of coexistence of them, and when total of K—O bonding and K-Metal bonding is set as 100% in a binding state around K-atom of the alkali niobate, a K—O bonding ratio is 46.5% or more and a K-Metal bonding ratio is 53.5% or less, wherein the Metal indicates a metal atom included in the piezoelectric film.

Abstract: There is provided a piezoelectric thin film element, comprising: a substrate 1; and a piezoelectric thin film 3 having an alkali niobium oxide-based perovskite structure represented by a composition formula (K1-xNax)yNbO3 provided on the substrate 1, wherein a carbon concentration of the piezoelectric thin film 3 is 2×1019/cm3 or less, or a hydrogen concentration of the piezoelectric thin film 3 is 4×1019/cm3 or less.

Abstract: A manufacturing method of a piezoelectric film element includes forming a lower electrode on a substrate, forming a piezoelectric film including a lead-free alkali niobate based compound having a perovskite structure on the lower electrode, forming a mask pattern on the piezoelectric film, dry-etching the piezoelectric film via the mask pattern, removing the mask pattern after the dry etching, and heat-treating the piezoelectric film in an oxidizing atmosphere. A manufacturing method of a piezoelectric device includes forming an upper electrode on the piezoelectric film of the piezoelectric film element formed by the manufacturing method of the piezoelectric film element, and connecting an electric voltage applying means or an electric voltage detecting means to the lower electrode and the upper electrode.

Abstract: A method for manufacturing a piezoelectric film wafer includes an etching step for carrying out a dry etching on a piezoelectric film formed on a substrate by using a gas containing Ar, and a step of changing a rate of the dry etching by detecting a change in an emission peak intensity of Na in emitted ion plasma the piezoelectric film. The piezoelectric film is made of an alkali niobate-based perovskite structure expressed in a composition formula (K1-xNax)NbO3 (0.4?x?0.7).

Abstract: A method for manufacturing a piezoelectric film wafer includes a first processing step for carrying out an ion etching on a KNN piezoelectric film formed on a substrate by using a gas containing Ar, and a second processing step for carrying out a reactive ion etching by using a mixed etching gas containing a fluorine-based reactive gas and Ar after the first processing step.