Tdk Corporation

Hisatoshi Saitou

Takao Noguchi

Hidenori Abe

Kenji Inoue

Eiju Komuro

Yoshihiko Yano

Yoshinari Yamashita

Masaaki Imura

A piezoelectric resonator includes; a lower electrodeformed on a substrate; a piezoelectric filmformed on the lower electrode; an upper electrodeformed on the piezoelectric filmand obtaining, in collaboration with the lower electrode, a signal having a predetermined resonance frequency by a propagation of a bulk acoustic wave inside the piezoelectric film; and an acoustic multilayer reflective filmincluding an SiOfilmhaving a predetermined acoustic impedance and an AIN filmhaving an acoustic impedance higher than the SiOfilm, and reflecting the bulk acoustic wave, the SiOfilmand the AIN filmbeing alternately stacked on the upper electrode, and the SiOfilmbeing in contact with the upper electrode

Piezoelectric resonator, filter and electronic component using the same

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.

Method of manufacturing a piezoelectric thin film resonator, manufacturing apparatus for a piezoelectric thin film resonator, piezoelectric thin film resonator, and electronic component

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.

Substrate for electronic device, electronic device and methods of manufacturing same

A filter device is provided which is low in power loss, small in size and operates in wide bands. The filter device includes a first signal-side resonator having an input signal electrode, an output signal electrode, a first piezoelectric film, an input electrode film, and a common electrode film being commonly used by a second signal-side resonator and sandwiching the first piezoelectric film using the input electrode film, a second signal-side resonator having a second piezoelectric film formed in layers on the first piezoelectric film, an output electrode film, a common electrode film sandwiching the second piezoelectric film using the output electrode film and being acoustically coupled to the first signal resonator, and a ground-side resonator connected between the common electrode film and a ground electrode and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to resonant frequencies in which the first and second signal-side resonators operate.

Filter device utilizing stacked resonators and acoustic coupling and branching filter using same

In a filter deviceconstituted by circuit elements formed on a single substrate, the circuit elements includes a first wing sectionformed between an input signal electrodeand an output signal electrode, first resonatorslocated in the first wiring sectionand having a predetermined resonance frequency, second wiring sectionsformed between the first wiring sectionand a ground electrode, second resonatorslocated in the second wiring sectionsand having an anti-resonance frequency forming a pass-band with the predetermined resonance frequency of the first resonators. An effective electric and mechanical coupling factor of the second resonatoris different from those of the other resonators

Filter device capable of obtaining attenuation characteristic of sharpness in narrow band width and branching filter using the same

A thin-film bulk acoustic oscillator comprises: a base; a barrier layer disposed on the base; a lower electrode disposed on the barrier layer; a piezoelectric thin film disposed on the lower electrode; and an upper electrode disposed on the piezoelectric thin film. The piezoelectric thin film includes a columnar crystal that extends in the direction intersecting the film surface. The top surface of the piezoelectric thin film is flattened by polishing so as to have a root mean square roughness of 2 nm or smaller.

Thin-film bulk acoustic oscillator and method of manufacturing same

A method for manufacturing a piezo-resonator including: a first step of forming an upper electrode layeron the piezoelectric film, a second step of coating the upper electrode layerwith a resistand of performing patterning on the resist so as to have a shape of the upper electrode, a third step of masking the patterned resistand removing the upper electrode layerother than masked portions and forming two or more first upper electrodes, a fourth step of removing the resist, a fifth step of coating the first upper electrodeswith a resist and performing patterning on the resist so that the first upper electrodesare partially exposed, a sixth step of etching each of the exposed first upper electrodesby a specified thickness to form a second upper electrode, and a seventh step of removing the resist

Method for manufacturing piezo-resonator

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.

Piezoelectric resonant filter and duplexer

An electronic device substrate structure including a substratea metal thin filmas 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 substrateand a wurtzite type thin filmas a (0001)-oriented film of a wurtzite crystal structure formed on the metal thin filmwherein: 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 filmis a (111)-oriented film, &#x3c;11-20&#x3e; axes in the plane of the wurtzite type thin filmare parallel to &#x3c;1-10&#x3e; axes in the plane of the metal thin filmand when the metal thin filmis a (0001)-oriented film, &#x3c;11-20&#x3e; axes in the plane of the wurtzite type thin filmare parallel to &#x3c;11-20&#x3e; axes in the plane of the metal thin film

Electronic device substrate structure and electronic device

The invention has for its objects to provide a multilayer thin film comprising a ferroelectric thin film preferentially (001) oriented on an Si substrate, its fabrication process, and an electron device. To attain these object, the invention provides a multilayer thin film formed on a substrate by epitaxial growth, which comprises a buffer layer comprising an oxide and a ferroelectric thin film, with a metal thin film and an oxide thin film formed in this order between the buffer layer and the ferroelectric thin film, its fabrication process, and an electron device.

Multilayer thin film and its fabrication process as well as electron device

An object of the invention is to provide a piezoelectric bulk acoustic wave device having a high effective electromechanical coupling constant and allowing a fractional bandwidth to be broadened when applied to a filter and a normalized frequency variable width to be broadened when applied to an oscillator. Another object of the invention is to provide a miniature piezoelectric bulk acoustic wave device capable of operating at a high frequency of several hundreds of megahertz while maintaining a high electromechanical coupling constant. The piezoelectric bulk acoustic wave device includes a piezoelectric substrate constructed of a single crystal or oriented crystal body of potassium niobate and having a pair of major surfaces, and at least one pair of opposed electrodes formed on the major surfaces of the piezoelectric substrate, respectively, wherein the device utilizes thickness vibration propagating along the major surfaces.

Piezoelectric bulk acoustic wave device

A thin film piezoelectric device has an epitaxial metal thin film (,) on a silicon substrate (,) and a PZT thin film (,) on the metal thin film, the PZT thin film (,) having a Ti/(Ti&plus;Zr) atomic ratio between 0.65 and 0.90. A film bulk acoustic resonator having an extremely broad band is realized.

Growing community of inventors

Tokyo, Japan

Hisatoshi Saitou