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US 7,280,007 B2Granted
Thin film bulk acoustic resonator with a mass loaded perimeter
AssigneeAvago Technologies General IP (Singapore) Pte. Ltd.
InventorsHongjun Feng, R. Shane Fazzio, Richard Ruby, Paul Bradley
Life of this patent
Estimating the term…
Abstract
A resonator structure (FBAR) made of electrodes sandwich a piezoelectric material. The intersection of the two conducting electrodes defines the active area of the acoustic resonator. The active area is divided into two concentric areas; a perimeter or frame, and a central region. An annulus is added to one of the two conducting electrodes to improve the electrical performance (in terms of Q).
Claims19
A device for trapping mechanical energy comprising:
- a first electrode;
- a second electrode positioned proximate and above the first electrode;
- the overlap of the first and the second electrodes defining an active area;
- a dielectric sheet of a type II piezoelectric material interposing the first and the second electrodes;
- a raised annulus positioned on a surface of one of the first and second electrodes;
- wherein the area within the raised annulus has a first acoustic impedance, the raised annulus has a second acoustic impedance, and the region external to the raised annulus has a third acoustic impedance;
- and
- the second acoustic impedance being greater than the first and the third acoustic impedances to improve the Q factor of the device near a parallel resonant frequency (fp) of the device.
5 more elements
A method for trapping mechanical energy, comprising:
- providing a first electrode;
- providing a second electrode positioned proximate and above the first electrode;
- the overlap of the first and the second electrodes defining an active area;
- providing a dielectric sheet of a type II piezoelectric material interposing the first and the second electrodes;
- providing a raised annulus positioned on a surface of one of the first and second electrodes;
- wherein the area within the raised annulus has a first acoustic impedance, the raised annulus has a second acoustic impedance, and the region external to the raised annulus has a third acoustic impedance;
- and
- the second acoustic impedance being greater than the first and the third acoustic impedances to improve a Q factor near a parallel resonant frequency (fp).
5 more elements
Dependencies are inferred from the claim text.