Abstract: A substrate for an electronic device comprises a base, an adhesion film stacked on the base, and a conductor film stacked on the adhesion film. The adhesion film is a non-epitaxial film including a crystal having a wurtzite crystal structure. The electronic device comprises the substrate and a functional film having a specific function and disposed on the substrate.

Abstract: A film bulk acoustic wave resonator of the invention includes a substrate; a resonant structure provided on the substrate constituted by a lower electrode, a piezoelectric film and an upper electrode; and an acoustic multilayer of a plurality of reflective films provided between the substrate and the resonant structure. At least one of the reflective films of the acoustic multilayer has a specified crystal plane orientation, and an X-ray rocking curve full width at half maximum that is preferably not greater than 10 degrees, and more preferably is not greater than 3 degrees. This makes it possible to obtain better resonance characteristics than in the case of the prior art, by increasing the efficiency with which bulk waves propagating towards the substrate are reflected.

Abstract: A piezoelectric resonator according to an embodiment of the present invention has a first transducer connected to a first signal terminal, and a second transducer connected to a second signal terminal. The first transducer and the second transducer are stacked in a predetermined direction. At least one of the first transducer and the second transducer has a first piezoelectric film sandwiched between a pair of electrode films on both sides, and a second piezoelectric film comprised of a film type different from that of the first piezoelectric film and sandwiched between a pair of electrode films on both sides.

Abstract: The present invention provides an electronic device with improved characteristics and a method of making the electronic device. In a method of making an electronic device (piezoelectric device) 74 according to the present invention, an outer edge R1 of a piezoelectric film 52A formed on an electrode film 46A of a laminate 60 is located inside an outer edge R2 of the electrode film 46A. For this reason, in removal of a monocrystalline Si substrate 14 from a multilayer board 61, where an etching solution permeates between polyimide 72 and laminate 60, the etching solution circumvents the electrode film 46A before it reaches the piezoelectric film 52A. Namely, a route A of the etching solution to the piezoelectric film 52A is significantly extended by the electrode film 46A. In the method of making the electronic device 74, therefore, the etching solution is less likely to reach the piezoelectric film 52A.

Abstract: The electronic device includes a substrate, a lower conductive film provided on the substrate, a functional film provided on the lower conductive film, and a crystallinity barrier film provided between the lower conductive film and the functional film. The present invention prevents the crystallinity of the functional film being affected by the crystallinity or the material selection of the lower conductive film, so it becomes possible to use a low-cost metal such as aluminum (Al) for the lower conductive film, and to use a low-cost method for forming the film, thereby making it possible to improve the crystallinity of the functional film without using a costly film-formation method such as epitaxial growth. For the crystallinity barrier film, there can be used a material having an amorphous structure.

Abstract: A piezoelectric resonator according to an embodiment of the present invention is a piezoelectric resonator for obtaining a signal of a predetermined resonance frequency from a bulk acoustic wave propagating inside a piezoelectric film. This piezoelectric resonator has a plurality of transducers stacked in a predetermined direction, and a propagation area of the bulk acoustic wave varies in a propagation direction of the bulk acoustic wave.

Abstract: An electronic device includes a substrate, a lower conductive film formed on the substrate and a functional film formed on the lower conductive film. In the present invention, an adhesion of the lower conductive film on the side of the substrate is greater than or equal to 0.1 N/cm. The electronic device according to this invention exhibits high mechanical strength that makes it very reliable. This is because the invention prevents the physical exfoliation of the lower conductive film that is apt to occur during or after fabrication of the electronic device when the adhesion of the lower conductive film is lower than 0.1 N/cm.

Abstract: A piezoelectric resonant filter includes a group of series resonators and a group of parallel resonators for forming a ladder-type filter circuit. Each of the resonators has a piezoelectric thin film having piezoelectric characteristic, and lower and upper electrodes disposed on opposite surfaces of the piezoelectric thin film for applying an excitation voltage to the piezoelectric thin film. The group of the parallel resonators exhibits a low frequency side attenuation extremum in the filter whereas the group of the series resonators exhibits a high frequency side attenuation extremum in the filter. At least one of the group of the series resonators and the group of the parallel resonators has a temperature compensating layer for bringing the temperature coefficient of the resonant frequency close to zero.

Abstract: A piezoelectric resonator according to an embodiment of the present invention has a first transducer connected to a first signal terminal, and a second transducer connected to a second signal terminal. The first transducer and the second transducer are stacked in a predetermined direction. At least one of the first transducer and the second transducer has a first piezoelectric film sandwiched between a pair of electrode films on both sides, and a second piezoelectric film comprised of a film type different from that of the first piezoelectric film and sandwiched between a pair of electrode films on both sides.

Abstract: Provided is a thin-film piezoelectric element which reduces the influence of an oxide film left on the electrode film on the degradation of element characteristics, and a method of making the thin-film piezoelectric element. The thin-film piezoelectric element has ZrO2 as the main component of the outermost layer of the oxide film which covers the laminate. Young's modulus of the ZrO2 is 190 GPa, giving a significantly low value compared with Young's modulus of MgO, 245 GPa. Consequently, the influence of the oxide film on the reduction in the displacement magnitude of the piezoelectric film is smaller than the influence of the MgO thin film left in the conventional thin-film piezoelectric element. As a result, the thin-film piezoelectric element decreases the influence of the oxide film on the degradation of element characteristics compared with the conventional thin-film piezoelectric element.

Abstract: A piezoelectric resonator according to an embodiment of the present invention is a piezoelectric resonator for obtaining a signal of a predetermined resonance frequency from a bulk acoustic wave propagating inside a piezoelectric film. This piezoelectric resonator has a plurality of transducers stacked in a predetermined direction, and a propagation area of the bulk acoustic wave varies in a propagation direction of the bulk acoustic wave.

Abstract: The electronic device includes a substrate, a lower conductive film provided on the substrate, a functional film provided on the lower conductive film, and a crystallinity barrier film provided between the lower conductive film and the functional film. The present invention prevents the crystallinity of the functional film being affected by the crystallinity or the material selection of the lower conductive film, so it becomes possible to use a low-cost metal such as aluminum (Al) for the lower conductive film, and to use a low-cost method for forming the film, thereby making it possible to improve the crystallinity of the functional film without using a costly film-formation method such as epitaxial growth. For the crystallinity barrier film, there can be used a material having an amorphous structure.

Abstract: A film bulk acoustic wave resonator of the invention includes a substrate; a resonant structure provided on the substrate constituted by a lower electrode, a piezoelectric film and an upper electrode; and an acoustic multilayer of a plurality of reflective films provided between the substrate and the resonant structure. At least one of the reflective films of the acoustic multilayer has a specified crystal plane orientation, and an X-ray rocking curve full width at half maximum that is preferably not greater than 10 degrees, and more preferably is not greater than 3 degrees. This makes it possible to obtain better resonance characteristics than in the case of the prior art, by increasing the efficiency with which bulk waves propagating towards the substrate are reflected.

Abstract: A component for fabricating the electronic device comprises a substrate and a conductive film provided on the substrate, in which the adhesion of the conductive film to the substrate is not greater than 0.1 N/cm. The adhesion of the conductive film to the substrate is weak enough to enable the conductive film to be readily peeled from the substrate. This makes it possible to form a component on a substrate other than the substrate used during film formation, thereby greatly increasing the degree of product configuration freedom. If the adhesion of a lower conductive film on the substrate side is made to be not greater than 0.04 N/cm, it becomes very easy to peel the conductive film from the substrate.

Abstract: An electronic device includes a substrate, a lower conductive film formed on the substrate and a functional film formed on the lower conductive film. In the present invention, an adhesion of the lower conductive film on the side of the substrate is greater than or equal to 0.1 N/cm. The electronic device according to this invention exhibits high mechanical strength that makes it very reliable. This is because the invention prevents the physical exfoliation of the lower conductive film that is apt to occur during or after fabrication of the electronic device when the adhesion of the lower conductive film is lower than 0.1 N/cm.

Abstract: An electronic device substrate structure including a substrate 2, a metal thin film 4 as a (111)-oriented film of a face-centered cubic structure or as a (0001)-oriented film of a hexagonal closest packed structure formed on the substrate 2, and a wurtzite type thin film 5 as a (0001)-oriented film of a wurtzite crystal structure formed on the metal thin film 4, wherein: each of the two thin films is a polycrystalline film containing at least two kinds of crystal grains different in direction of crystal orientation in the plane; when the metal thin film 4 is a (111)-oriented film, <11-20> axes in the plane of the wurtzite type thin film 5 are parallel to <1-10> axes in the plane of the metal thin film 4; and when the metal thin film 4 is a (0001)-oriented film, <11-20> axes in the plane of the wurtzite type thin film 5 are parallel to <11-20> axes in the plane of the metal thin film 4.

Abstract: A substrate for an electronic device comprises a base, an adhesion film stacked on the base, and a conductor film stacked on the adhesion film. The adhesion film is a non-epitaxial film including a crystal having a wurtzite crystal structure. The electronic device comprises the substrate and a functional film having a specific function and disposed on the substrate.

Abstract: A method of manufacturing a piezoelectric thin film resonator forms, after forming a piezoelectric film on a substrate so as to cover a lower electrode formed on the substrate, an electrode material layer for forming an upper electrode above the piezoelectric film, forms a mask of a predetermined form on the electrode material layer, and then etches the electrode material layer to form the upper electrode. Before a step of forming the electrode material layer, a protective layer for protecting the piezoelectric film during etching of the electrode material layer is formed so as to cover at least a part of the piezoelectric film where the upper electrode is not formed, and the electrode material layer is then formed so as to cover the protective layer.

Abstract: A piezoelectric resonant filter includes a group of series resonators and a group of parallel resonators for forming a ladder-type filter circuit. Each of the resonators has a piezoelectric thin film 15 having piezoelectric characteristic, and lower and upper electrodes 14 and 16 disposed on opposite surfaces of the piezoelectric thin film 15 for applying an excitation voltage to the piezoelectric thin film 15. The group of the parallel resonators exhibits a low frequency side attenuation extremum in the filter whereas the group of the series resonators exhibits a high frequency side attenuation extremum in the filter. At least one of the group of the series resonators and the group of the parallel resonators has a temperature compensating layer 20 for bringing the temperature coefficient of the resonant frequency close to zero.

Abstract: An electronic device substrate structure including a substrate 2, a metal thin film 4 as a (111)-oriented film of a face-centered cubic structure or as a (0001)-oriented film of a hexagonal closest packed structure formed on the substrate 2, and a wurtzite type thin film 5 as a (0001)-oriented film of a wurtzite crystal structure formed on the metal thin film 4, wherein: each of the two thin films is a polycrystalline film containing at least two kinds of crystal grains different in direction of crystal orientation in the plane; when the metal thin film 4 is a (111)-oriented film, <11-20> axes in the plane of the wurtzite type thin film 5 are parallel to <1-10> axes in the plane of the metal thin film 4; and when the metal thin film 4 is a (0001)-oriented film, <11-20> axes in the plane of the wurtzite type thin film 5 are parallel to <11-20> axes in the plane of the metal thin film 4.