ACOUSTIC BANDGAP STRUCTURES FOR INTEGRATION OF MEMS RESONATORS
First Claim
1. An acoustic bandgap device formed using a semiconductor fabrication tool, the semiconductor fabrication tool having a minimal feature thickness and an allowable via width based on a design rule check of the semiconductor fabrication tool, the device comprising:
- a substrate lying in an x-y plane defining an x-direction and a y-direction;
an acoustic resonant cavity disposed over the substrate;
a phononic crystal disposed over the acoustic resonant cavity, the phononic crystal comprising a plurality of unit cells disposed in a periodic arrangement, each unit cell comprising;
(i) at least one higher acoustic impedance structure having a longitudinal axis oriented in the y-direction and a thickness in the x-direction greater than or about equal to the minimal feature thickness of the semiconductor fabrication tool, the at least one higher acoustic impedance structure comprising at least one of;
at least one via structure, each via structure having a width in the x-direction about equal to the allowable via width of the semiconductor fabrication tool; and
at least one longitudinal bar, each longitudinal bar having a width in the x-direction greater than the width of the at least one via structure; and
(ii) at least one lower acoustic impedance material bordering at least a portion of the at least one higher acoustic impedance structure and forming at least a portion of a remainder of the respective unit cell;
wherein a ratio of an acoustic impedance of the higher acoustic impedance structure to an acoustic impedance of the lower acoustic impedance material is greater than 1.0; and
wherein the phononic crystal suppresses phononic excitations in at least one frequency band, thereby providing at least one phononic bandgap.
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Accused Products
Abstract
Example acoustic bandgap devices provided that can be fabricated in a semiconductor fabrication tool based on design check rules. An example device includes a substrate lying in an x-y plane and defining an x-direction and a y-direction, an acoustic resonant cavity over the substrate, and a phononic crystal disposed over the acoustic resonant cavity by generating the phononic crystal as a plurality of unit cells disposed in a periodic arrangement. Each unit cell include: (a) at least one higher acoustic impedance structure having a longitudinal axis oriented in the y-direction and a thickness in the x-direction greater than or about equal to a minimal feature thickness of the semiconductor fabrication tool, and (b) at least one lower acoustic impedance material bordering at least a portion of the at least one higher acoustic impedance structure and forming at least a portion of a remainder of the respective unit cell.
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Citations
31 Claims
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1. An acoustic bandgap device formed using a semiconductor fabrication tool, the semiconductor fabrication tool having a minimal feature thickness and an allowable via width based on a design rule check of the semiconductor fabrication tool, the device comprising:
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a substrate lying in an x-y plane defining an x-direction and a y-direction; an acoustic resonant cavity disposed over the substrate; a phononic crystal disposed over the acoustic resonant cavity, the phononic crystal comprising a plurality of unit cells disposed in a periodic arrangement, each unit cell comprising; (i) at least one higher acoustic impedance structure having a longitudinal axis oriented in the y-direction and a thickness in the x-direction greater than or about equal to the minimal feature thickness of the semiconductor fabrication tool, the at least one higher acoustic impedance structure comprising at least one of; at least one via structure, each via structure having a width in the x-direction about equal to the allowable via width of the semiconductor fabrication tool; and at least one longitudinal bar, each longitudinal bar having a width in the x-direction greater than the width of the at least one via structure; and (ii) at least one lower acoustic impedance material bordering at least a portion of the at least one higher acoustic impedance structure and forming at least a portion of a remainder of the respective unit cell; wherein a ratio of an acoustic impedance of the higher acoustic impedance structure to an acoustic impedance of the lower acoustic impedance material is greater than 1.0; and wherein the phononic crystal suppresses phononic excitations in at least one frequency band, thereby providing at least one phononic bandgap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of producing an acoustic bandgap device formed using a semiconductor fabrication tool, the semiconductor fabrication tool having a minimal feature thickness and an allowable via width based on a design rule check of the semiconductor fabrication tool, the method comprising:
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fabricating an acoustic resonant cavity over a substrate lying in an x-y plane defining an x-direction and a y-direction; fabricating a phononic crystal over the acoustic resonant cavity using a method comprising; (i) generating the phononic crystal as a plurality of unit cells disposed in a periodic arrangement, each unit cell comprising; a) at least one higher acoustic impedance structure having a longitudinal axis oriented in the y-direction and a thickness in the x-direction greater than or about equal to a minimal feature thickness of the semiconductor fabrication tool, the at least one higher acoustic impedance structure comprising at least one of; at least one via structure, each via structure having a width in the x-direction about equal to an allowable via width of the semiconductor fabrication tool; and at least one longitudinal bar, each longitudinal bar having a width in the x-direction greater than the width of the at least one via structure; and b) at least one lower acoustic impedance material bordering at least a portion of the at least one higher acoustic impedance structure and forming at least a portion of a remainder of the respective unit cell; wherein a ratio of an acoustic impedance of the higher acoustic impedance structure to an acoustic impedance of the lower acoustic impedance material is greater than 1.0; and wherein the phononic crystal suppresses phononic excitations in at least one frequency band, thereby providing at least one phononic bandgap. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification