1659 results about "Piezoelectric thin films" patented technology

Surface acoustic wave device having a high k<2>, and a frequency filter, oscillator, electronic circuit and electronic device employing this surface acoustic wave device is provided, wherein a first oxide thin film layer comprising SrO or MgO and a second oxide thin film layer comprising SrTiO3 are sequentially formed on top of a (110) Si substrate, or a first oxide thin film layer comprising CeO2, ZrO2 or yttrium-stabilized zirconia and a second oxide thin film layer comprising SrTiO3 are sequentially formed on top of a (100) Si substrate, a KNbO3 piezoelectric thin film being then formed on top of either of these second oxide thin film layers, and then, a protective film comprising oxide or nitride is formed on top of the KNbO3 piezoelectric thin film, finally, at least one electrode is formed on top of this protective film, to form a surface acoustic wave device, which surface acoustic wave device is employed to form a frequency filter, oscillator, electronic circuit, or electronic device.

A piezoelectric thin film sensor array is used to scan and capture biometric data, for example, a fingerprint image. In one embodiment, a multi-layer structure includes a PVDF layer in between two conductor grids arranged orthogonally to one another. Urethane can be added to one side where a finger is placed. A foam substrate can be used as a support. In one feature, the PVDF, and grids can be peeled off like a label for easy replacement. Multiplexers are switched to scan the sensor. A single pixel or a group of pixels can be detected and output to an image memory. The presence of a fingerprint ridge is detected by virtue of a ring-down oscillation that arises from reflection when an electric field is applied to the piezoelectric thin film sensor array at a pixel in contact with the fingerprint ridge. For example, such a ring-down value associated with a fingerprint ridge can be detected at about 150 ns. (or 5 cycles at 30 MHZ). Other reflections indicative of additional biometrics (e.g. from tissue, blood, bone, fingernail, etc.) can also be detected. A Doppler effect due to reflections from circulating blood can also be detected. Such a Doppler effect can provide further information about direction and speed of blood circulation. An instantaneous pyroelectric effect can also be detected to indicate a live finger presence.

A piezoelectric resonator that achieves stable quality and improved resonance characteristics includes an acoustic reflector portion disposed between a substrate and a vibration portion, which includes a piezoelectric thin film sandwiched between a pair of electrodes, and a plurality of low acoustic impedance layers made of a material having relatively low acoustic impedance and a plurality of high acoustic impedance layers formed made of a material having relatively high acoustic impedance, the acoustic impedance layers being disposed alternately, and adjustment layers, which are disposed between the high acoustic impedance layers and the low acoustic impedance layers on the substrate sides of the high acoustic impedance layers and which have an acoustic impedance value intermediate between that of the high acoustic impedance layers and that of the low acoustic impedance layers. The low acoustic impedance layers and the high acoustic impedance layers have compressive stresses and the adjustment layers have a tensile stress.

A piezoelectric thin-film resonator includes a supporting substrate. A piezoelectric thin-film is formed on the supporting substrate. A lower electrode and an upper electrode are formed with the piezoelectric thin-film therebetween. The stiffness of at least one of the lower and upper electrodes is higher than that of the piezoelectric thin-film.

A piezoelectric thin film resonator has a substrate and a piezoelectric layered structure including a lower electrode, piezoelectric aluminum nitride thin film with c-axis orientation and upper electrode formed on the substrate in this order. The lower electrode are made of a metal thin film including a layer containing ruthenium as a major component having a full-width half maximum (FWHM) of a rocking curve of a (0002) diffraction peak of ruthenium of 3.0° or less. The piezoelectric aluminum nitride thin film formed on the lower electrode has a full-width half maximum (FWHM) of a rocking curve of a (0002) diffraction peak of 2.0° or less.