An electric controlled bi-directional bending actuator with deformability and stiffness tunable capacity is disclosed. The electric controlled bi-directional bending actuator with deformability and stiffness tunable capacity comprises three kinds of functional layers that are electro-deformable layers, electro-variable stiffness layers and flexible electrodes. From up to bottom, they are the first flexible electrodes layer, the first electro-deformable layer, the second flexible electrodes layer, the electro-variable stiffness layer, the third flexible electrode layer, the second electro-deformable layer and the fourth flexible electrode layer. The adjacent layers are glued together. The electro-deformable layer is made from dielectric elastomers. The electro-variable stiffness layer is made from electro-rheological materials, including electro-rheological fluids, electro-rheological gels or electro-rheological elastomers. Compared with the present pneumatic actuators with deformability and stiffness tunable capacity, the invention has such merits as simple structure, precise regulation, quick response, convenient control and insensitive to environmental.

An acoustic wave device fabrication method includes: forming on a piezoelectric substrate a comb-shaped electrode and a wiring layer coupled to the comb-shaped electrode; forming on the piezoelectric substrate a first dielectric film having a film thickness greater than those of the comb-shaped electrode and the wiring layer, covering the comb-shaped electrode and the wiring layer, and being made of silicon oxide doped with an element or undoped silicon oxide; forming on the first dielectric film a second dielectric film having an aperture above the wiring layer; removing the first dielectric film exposed by the aperture of the second dielectric film by wet etching using an etching liquid causing an etching rate of the second dielectric film to be less than that of the first dielectric film so that the first dielectric film is left so as to cover an end face of the wiring layer and the comb-shaped electrode.

In a MEMS device in which a first electrode layer, a piezoelectric layer, and a second electrode layer are stacked in this order from a first surface side of a substrate, a first wiring layer is stacked on a second surface on a side opposite to a first surface of the substrate and the first electrode layer and the first wiring layer are connected to each other via a through wiring passing through the substrate.

A piezoelectric element includes, on a base, an underlying layer for controlling crystallinity of a piezoelectric layer, and the piezoelectric layer. The piezoelectric layer includes a crystal with an ABO.sub.3-type structure having at least Pb at A sites. In the underlying layer, an interface-with-the-base side is configured including at least Pb and another substance with a different composition rate from that of the piezoelectric layer at the A sites, and a substance with a different composition ratio from that of the piezoelectric layer at B sites. In a layer above the interface-with-the-base side in the underlying layer, the composition rate of the other substance included at the A sites of the underlying layer progressively changes and also the composition ratio of the substance included at the B sites progressively changes, from the interface-with-the-base side toward the interface-with-the-piezoelectric-layer side to approach the composition of the piezoelectric layer.

According to one aspect of the invention, there is proposed a capacitive radiofrequency MicroElectroMechanical System or capacitive RF MEMS comprising a metallic membrane suspended above an RF transmission line and resting on ground planes, and exhibiting a lower face, an upper face opposite to the lower face and a first layer comprising a refractory metallic material at least partially covering the upper face of the membrane so as to prevent the heating of the membrane.

An acoustic wave device includes: a piezoelectric thin film resonator that is connected between a first node and a second node; and a resonant circuit that is connected in parallel with the piezoelectric thin film resonator between the first node and the second node, and has a resonant frequency f0 that meets a condition of 2×fa×0.92≦f0 where fa represents an antiresonant frequency of the piezoelectric thin film resonator.

Switchable and/or tunable filters, methods of manufacture and design structures are disclosed herein. The method of forming the filters includes forming at least one piezoelectric filter structure comprising a plurality of electrodes formed on a piezoelectric substrate. The method further includes forming a fixed electrode with a plurality of fingers on the piezoelectric substrate. The method further includes forming a moveable electrode with a plurality of fingers over the piezoelectric substrate. The method further includes forming actuators aligned with one or more of the plurality of fingers of the moveable electrode.

Disclosed is a piezoelectric element wherein a lower electrode made of Pt, a buffer layer made of PLT, and a piezoelectric thin film to be a perovskite ferroelectric thin film are formed in this order on a substrate. The average crystal grain size of Pt forming the lower electrode is not smaller than 50 nm and not larger than 150 nm.

A piezoelectric actuator includes a piezoelectric element that includes a piezoelectric unit including a ferroelectric, which has an asymmetric bipolar P-E curve, a capacitor connected to the piezoelectric unit in series, and a resistor connected to the capacitor in series and connected to the ferroelectric in parallel; and a drive unit that inputs a drive waveform Vd, which includes a DC offset component of which polarity is opposite to polarization of the ferroelectric, to the piezoelectric element to drive the piezoelectric element. A value of a coercive electric field Ec.sub.1, a value of a coercive electric field Ec.sub.2, the capacitance C.sub.s of the capacitor, the capacitance C.sub.pz of the ferroelectric, combined resistance R.sub.p of the resistance of the resistor and the resistance of the ferroelectric, and a fundamental angular frequency ω of the drive waveform satisfy Expressions I to III, wherein

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An aspect of the present invention relates to a vibration element comprising: a substrate; a ceramic layer containing glass and provided on the substrate; and a piezoelectric element comprising an electrode layer fixed to the substrate with the ceramic layer therebetween and a piezoelectric layer, wherein the piezoelectric layer, the electrode layer, the substrate, and the ceramic layer are integrated by the piezoelectric layer, the electrode layer, the substrate, and the ceramic layer being sintered together at a sintering temperature of from 800° C. or higher to 940° C. or lower.