Avago Technologies General IP (singapore) Pte. Ltd.

Avago Technologies International Sales Pte. Limited

Avago Technologies Wireless IP (singapore) Pte. Ltd.

Chris Feng

John Choy

Phil Nikkel

Kevin J Grannen

Dariusz Burak

Tina L Lamers

Alexandre Shirakawa

Stefan Bader

Qiang Zou

Tangshiun Yeh

Paul D Bradley

Ivan Ionash

John Dwight Larson, Iii

Kristina Lamers

Steve Gilbert

Sook Ching Chang

Tom Yeh

An acoustic resonator is disclosed. The acoustic resonator comprises a substrate, a first electrode, a second electrode and a piezoelectric layer positioned between the first electrode and the second electrode. An acoustic reflector is positioned between the first electrode and the substrate. An active area comprises a region of contacting overlap of the acoustic reflector, the first electrode, the piezoelectric layer and the second electrode. A gap region extends around the active area.

Acoustic resonator structure having an electrode with a cantilevered portion

A bulk acoustic wave (BAW) resonator includes: a substrate; an acoustic reflector disposed in the substrate; a first electrode disposed over the acoustic reflector; a second electrode; and a piezoelectric layer between the first and second electrodes. The second electrode is not disposed between the first electrode and the acoustic reflector. The BAW resonator further includes a block disposed over the substrate and beneath the piezoelectric layer. A contacting overlap of the acoustic reflector, the first electrode, the second electrode and the piezoelectric layer defines an active area of the BAW resonator.

Bulk acoustic wave resonator

An acoustic resonator device includes a composite first electrode disposed over a substrate; a piezoelectric layer disposed on the composite first electrode, the piezoelectric layer including a piezoelectric material doped with scandium for improving piezoelectric properties; and a second electrode disposed on the piezoelectric layer. The composite first electrode includes a base electrode layer disposed over the substrate; a temperature compensation layer disposed on the base electrode layer; a seed interlayer disposed on the temperature compensation layer, the seed interlayer having a thickness between about 5&#x212b; and about 150&#x212b;; and a conductive interposer layer disposed on at least the seed interlayer, at least a portion of the conductive interposer layer contacting the base electrode layer. The piezoelectric layer has a negative temperature coefficient and the temperature compensation layer has a positive temperature coefficient at least partially offsetting the negative temperature coefficient.

Temperature compensated acoustic resonator device having thin seed interlayer

An acoustic resonator comprises a first electrode and second electrode comprising a plurality of sides. At least one of the sides of the second electrode comprises a cantilevered portion. A piezoelectric layer is disposed between the first and second electrodes. A bridge disposed adjacent to one of the sides of the second electrode.

A method is provided for forming a piezoelectric layer during a corresponding deposition sequence. The method includes sputtering aluminum nitride onto a sputtering substrate inside a reaction chamber having a gas atmosphere, the gas atmosphere initially including nitrogen gas and an inert gas, causing growth of the piezoelectric layer with a polarity in a negative direction. The method further includes adding a predetermined amount of oxygen containing gas to the gas atmosphere over a predetermined period of time, while continuing the sputtering of the aluminum nitride onto the sputtering substrate during a remainder of the deposition sequence, such that the piezoelectric layer is monolithic. The predetermined amount of oxygen containing gas causes the polarity of the aluminum nitride piezoelectric layer to invert from the negative direction to a positive direction, opposite the negative direction.

Acoustic resonator including monolithic piezoelectric layer having opposite polarities

A bulk acoustic wave (BAW) resonator having a first electrode, a second electrode, and a piezoelectric layer between the first electrode and the second electrode. The first electrode is of a first electrode material. The second electrode is of a second electrode material. The piezoelectric layer is of a piezoelectric material doped with at least one rare earth element. The BAW resonator has a resonant frequency dependent at least in part on respective thicknesses and materials of the first electrode, the second electrode and the piezoelectric layer. The resonant frequency has a temperature coefficient. At least one of the first electrode and the second electrode includes a niobium alloy electrode material that, relative to molybdenum as the electrode material, reduces the temperature coefficient of the resonant frequency of the BAW resonator.

Bulk acoustic wave devices with temperature-compensating niobium alloy electrodes

An acoustic resonator comprises a first electrode, a second electrode and a piezoelectric layer disposed between the first electrode and the second electrode, and comprising a C-axis having an orientation. A polarization-determining seed layer (PDSL) is disposed beneath the piezoelectric layer, the seed layer comprising a metal-nonmetal compound. A method of fabricating a piezoelectric layer over a substrate comprises forming a first layer of a polarization determining seed layer (PDSL) over the substrate. The method further comprises forming a second layer of the PDSL over the first layer. The method further comprises forming a first layer of a piezoelectric material over the second layer of the PDSL; and forming a second layer of the piezoelectric material over the first layer of the piezoelectric material. The piezoelectric material comprises a compression axis (C-axis) oriented along a first direction.

Polarity determining seed layer and method of fabricating piezoelectric materials with specific C-axis

A solid mount bulk acoustic wave resonator, comprises a first electrode; a second electrode; a piezoelectric layer disposed between the first and second electrodes; and an acoustic reflector comprising a plurality of layers and disposed beneath the first electrode, the second electrode and the piezoelectric layer. An overlap of the acoustic reflector, the first electrode, the second electrode and the piezoelectric layer defines an active area of the acoustic resonator, and the piezoelectric layer extends over an edge of the first electrode. The acoustic resonator also comprises a bridge adjacent to a termination of the active area of the acoustic resonator. The bridge overlaps a portion of the first electrode.

Solid mount bulk acoustic wave resonator structure comprising a bridge

A method of forming an acoustic resonator includes forming a seed layer on a first electrode layer, forming a piezoelectric layer directly on a surface of the seed layer, and forming a second electrode layer on the piezoelectric layer. The piezoelectric layer includes multiple crystals of piezoelectric material, and the seed layer causes crystal axis orientations of the crystals to be substantially perpendicular to the surface of the seed layer.

Method of forming acoustic resonator using intervening seed layer

An acoustic resonator structure comprises a first electrode disposed on a substrate, a piezoelectric layer disposed on the first electrode and comprising aluminum scandium nitride, a second electrode disposed on the piezoelectric layer, and a temperature compensation feature having a temperature coefficient offsetting at least a portion of a temperature coefficient of the piezoelectric layer, the first electrode, and the second electrode.

Acoustic resonator comprising aluminum scandium nitride and temperature compensation feature

An acoustic resonator device includes a bottom electrode disposed on a substrate over an acoustic reflecting feature, a piezoelectric layer disposed on the bottom electrode and a top electrode disposed on the piezoelectric layer, where an overlap between the top electrode, the piezoelectric layer and the bottom electrode over the acoustic reflecting feature define an active region of the acoustic resonator device. The acoustic resonator device further includes at least one of a wing having an outer edge extending beyond at least a portion of an outer edge of the top electrode, and a first frame formed in one of an outer region or a center region of the top electrode. The at least one of the wing and the first frame has an apodized shape, such that no edges are parallel to one another, the apodized shape of the at least one of the wing and the first frame being different from an electrode shape defined by an outer edge of the top electrode.

Acoustic resonator device with structures having different apodized shapes

A bulk acoustic wave (BAW) resonator includes a first electrode; a second electrode; and a piezoelectric layer disposed between the first and second electrodes. The piezoelectric layer includes a piezoelectric material doped with at least one rare earth element. In an embodiment, the BAW resonator includes a recessed frame element disposed over a surface of at least one of the first and second electrodes. In another embodiment, the BAW resonator includes a raised frame element disposed over a surface of at least one of the first and second electrodes. In yet another embodiment, the BAW resonator includes both the raised and recessed frame elements.

Bulk acoustic wave resonators having doped piezoelectric material and frame elements

In accordance with a representative embodiment, a bulk acoustic wave (BAW) resonator comprises: a first electrode having a first electrode thickness; a second electrode having a second electrode thickness; and a piezoelectric layer having a piezoelectric layer thickness and being disposed between the first and second electrodes, the piezoelectric layer comprising a piezoelectric material doped with at least one rare earth element. For a particular acoustic coupling coefficient (kt) value and a series resonance frequency (F) of the BAW resonator, the first electrode thickness and the second electrode thickness are each greater than a thickness of a first electrode and a thickness of a second electrode of a BAW resonator comprising an undoped piezoelectric layer.

Bulk acoustic wave resonator having doped piezoelectric layer

A bulk acoustic wave (BAW) resonator, comprises: a first electrode; a second electrode comprising a plurality of sides. At least one of the sides comprises a cantilevered portion. The bulk acoustic wave (BAW) resonator also comprises a piezoelectric layer disposed between the first and second electrodes. The piezoelectric layer comprises an undoped piezoelectric material and a doped piezoelectric material, and the cantilevered portion extends above the piezoelectric layer. The bulk acoustic wave (BAW) resonator comprises a gap between the cantilevered portion and the piezoelectric layer.

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Fort Collins, CO, United States of America

Chris Feng