Multiple layer acoustical structures for thin-film resonator based circuits and systems

Claim 2

A thin film resonator device, comprising: a thin film resonator; a substrate underlying and mechanically supporting the resonator, and an acoustical isolator disposed between and joining the resonator and the substrate and comprising layers of non-lossless material having characteristic impedances and thicknesses selected to present a nominal impedance to the thin film resonator such as would be found if the thin film resonator were coupled to air.

Claim 3

A stacked thin film device structure grown on a substrate, comprising; a thin film device comprising at least one piezoelectric crystal layer sandwiched between electrodes, and constructed to have an acoustic response and a given frequency range; an acoustical stack disposed between and joining the thin film device and the substrate and comprising multiple layers of material, each layer having a characteristic thickness and impedance and being composed of a non-lossless material, the characteristic thickness and impedances of the layers being adjusted to determine the input impedance presented to the thin film device, and thereby determining the acoustical coupling between the thin film device and the substrate; and wherein the acoustical stack is an acoustical isolator presenting a nominal input impedance to the thin film device mimicking an acoustical short circuit such as would be found if said thin film resonator were coupled to air, the isolator comprising a sufficient number of layers having characteristic thicknesses and impedances adjusted to cause the isolator to present an iterative impedance to the thin film device which meets an isolation condition in the given frequency range, thereby isolating the thin film device from the substrate.

Claim 4

A stacked thin film device structure grown on a substrate, comprising; a thin film device comprising at least one piezoelectric crystal layer sandwiched between electrodes, and constructed to have an acoustic response and a given frequency range; an acoustical stack disposed between and joining the thin film device and the substrate and comprising multiple layers of material, each layer having a characteristic thickness and impedance and being composed of a non-lossless material, the characteristic thickness and impedances of the layers being adjusted to determine the input impedance presented to the thin film device, and thereby determining the acoustical coupling between the thin film device and the substrate; and wherein the acoustical stack is an acoustical isolator presenting a nominal input impedance to the thin film device mimicking an acoustical short circuit such as would be found if said thin film resonator were coupled to air, the isolator comprising a sufficient number of layers having characteristic thicknesses and impedances adjusted to cause the isolator to present an iterative impedance to the thin film device which meets an isolation condition in the given frequency range, thereby isolating the thin film device from the substrate.

Claim 5

The stacked thin film device structure according to claim 2, wherein the sufficient number is at least six.

Claim 6

The stacked thin film device structure according to claim 2, wherein the acoustical isolator is a cascaded stack of stack pairs, each stack pair constituent having a thickness equal to one quarter the wavelength of an acoustical wave in the given frequency range of the thin film device.

Claim 7

The stacked thin film device structure according to claim 4, wherein each stack pair is comprised of a first constituent having a relatively higher characteristic impedance, and a second constituent having a relatively lower characteristic impedance.

Claim 8

The stacked thin film device structure according to claim 5, wherein the first stack pair constituent is chromium, and the second stack pair constituent is aluminum.

Claim 9

The stacked thin film device structure according to claim 5, wherein the first stack pair constituent is copper, and the second stack pair constituent is aluminum.

Claim 10

The stacked thin film device structure according to claim 5, wherein three or more stacked pairs are cascaded to form the acoustical isolator.

Claim 11

The stacked thin film device structure according to claim 5, wherein the acoustical stack includes an uppermost stack pair, the top constituent of the uppermost stack pair also forming a bottom electrode for the thin film device.

Claim 12

The stacked thin film device of claim 4, wherein each stack pair is composed of different materials.

Claim 13

The stacked thin film device structure according to claim 2, wherein the thin film device is a thin film resonator.

Claim 14

The stacked thin film device structure according to claim 2, wherein the constituent material of the layers is selected to provide temperature compensation to the thin film device.

Claim 15

A thin film resonator device, comprising: a thin film resonator; a substrate underlying and mechanically supporting the resonator, and an acoustical isolator disposed between and joining the resonator and the substrate and comprising at least six layers of non-lossless material having characteristic impedances and thicknesses adjusted to present a nominal input impedance to the resonator which acoustically isolates the resonator and substrate.

Claim 16

A thin film resonator device, comprising: a thin film resonator; a substrate underlying and mechanically supporting the resonator, and an acoustical isolator disposed between and joining the resonator and the substrate and comprising at least six layers of non-lossless material having characteristic impedances and thicknesses adjusted to present a nominal input impedance to the resonator which acoustically isolates the resonator and substrate.