Patent US5646583A successfully refreshed from Google Patents.
US5646583A
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US
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Acoustic isolator having a high impedance layer of hafnium oxide
Assignee: Teledyne Scientific and Imaging LLC
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Filing: 1996-01-04
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Granted: 1997-07-08
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Expires: 2016-01-04
Abstract
Abstract A resonant acoustic isolator supports a thin film acoustic resonator comprising a layer of piezoelectric material having top and bottom electrical contacts. The resonant acoustic isolator comprises at least one pair of layers of materials having different acoustic impedances. The isolator materials are deposited in alternating layers of high and low impedance material, with each layer having a thickness of 1/4 acoustic wavelength at resonant frequency. Silicon dioxide (SiO 2 ) is preferred for the low impedance material because it is ubiquitous in the semiconductor industry, it has relatively low acoustic impedance with very low intrinsic acoustic loss, and it can be deposited using a variety of convenient methods. Hafnium oxide (HfO 2 ) is preferred for the high acoustic impedance material because it can be deposited by evaporation to form a hard, dense dielectric having a relatively high acoustic impedance. Deposition of an entire stack of alternating SiO 2 and HfO 2 layers can be performed in the same chamber using electron beam deposition techniques for low cost production.
Inventors
- 👤 Charles W. Seabury
- 👤 Paul H. Kobrin
- 👤 Jeffrey F. DeNatale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:46
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/15; H03H9/17; H03H9/171; H03H9/172; H03H9/175
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
53 words
A resonant acoustic isolator, comprising: a substrate; a pair of layers deposited on said substrate; said pair of layers comprising a first layer of material having a high acoustic impedance and a second layer of material having a low acoustic impedance; and said first layer of high acoustic impedance material comprising hafnium oxide.
Claim 2
Dependent Claim
53 words
A resonant acoustic isolator, comprising: a substrate; a pair of layers deposited on said substrate; said pair of layers comprising a first layer of material having a high acoustic impedance and a second layer of material having a low acoustic impedance; and said first layer of high acoustic impedance material comprising hafnium oxide.
Claim 3
Dependent Claim
19 words
The resonant acoustic isolator of claim 1, wherein said second layer of low acoustic impedance material comprises silicon dioxide.
Claim 4
Dependent Claim
33 words
The resonant acoustic isolator of claim 1, further comprising a plurality of pairs of said first and second layers forming a stack of alternating layers of said high and low acoustic impedance materials.
Claim 5
Dependent Claim
24 words
The resonant acoustic isolator of claim 1, further comprising a thin film acoustic resonator formed atop said second layer of low acoustic impedance material.
Claim 6
Dependent Claim
30 words
The resonant acoustic isolator of claim 4, wherein each of said first and second layers has a thickness of 1/4 acoustic wavelength at a resonant frequency of said acoustic resonator.
Claim 7
Dependent Claim
24 words
The resonant acoustic isolator of claim 1, wherein said first layer of hafnium oxide is deposited by electron beam evaporation with concurrent ion bombardment.
Claim 8
Dependent Claim
18 words
The resonant acoustic isolator of claim 1, wherein said first layer of hafnium oxide is deposited by sputtering.
Claim 9
Dependent Claim
56 words
A resonant acoustic isolator for a thin film acoustic resonator, comprising: a substrate; a pair of layers formed on said substrate, said pair of layers including a first layer of high acoustic impedance hafnium oxide and a second layer of low acoustic impedance material; and the thin film acoustic resonator formed atop said pair of layers.
Claim 10
Dependent Claim
56 words
A resonant acoustic isolator for a thin film acoustic resonator, comprising: a substrate; a pair of layers formed on said substrate, said pair of layers including a first layer of high acoustic impedance hafnium oxide and a second layer of low acoustic impedance material; and the thin film acoustic resonator formed atop said pair of layers.
Claim 11
Dependent Claim
19 words
The resonant acoustic isolator of claim 8, wherein said second layer of low acoustic impedance material comprises silicon dioxide.
Claim 12
Dependent Claim
36 words
The resonant acoustic isolator of claim 8, further comprising a plurality of pairs of said first and second layers forming a stack of alternating layers of said high and low acoustic impedance materials on said substrate.
Claim 13
Dependent Claim
27 words
The resonant acoustic isolator of claim 8, wherein each of said layers has a thickness of 1/4 acoustic wavelength at a resonant frequency of the acoustic resonator.
Claim 14
Dependent Claim
24 words
The resonant acoustic isolator of claim 8, wherein said first layer of hafnium oxide is deposited by electron beam evaporation with concurrent ion bombardment.
Claim 15
Dependent Claim
18 words
The resonant acoustic isolator of claim 8, wherein said first layer of hafnium oxide is deposited by sputtering.
Claim 16
Dependent Claim
86 words
A thin film acoustic resonator having a resonant acoustic isolator, comprising: a substrate; at least one pair of alternating layers deposited on said substrate to form the resonant acoustic isolator; each of said at least one pair of alternating layers including a first layer of high acoustic impedance hafnium oxide and a second layer of low acoustic impedance material; and the thin film resonator comprising a layer of piezoelectric material with top and bottom electrical contacts formed on said at least one pair of alternating layers.
Claim 17
Dependent Claim
86 words
A thin film acoustic resonator having a resonant acoustic isolator, comprising: a substrate; at least one pair of alternating layers deposited on said substrate to form the resonant acoustic isolator; each of said at least one pair of alternating layers including a first layer of high acoustic impedance hafnium oxide and a second layer of low acoustic impedance material; and the thin film resonator comprising a layer of piezoelectric material with top and bottom electrical contacts formed on said at least one pair of alternating layers.
Claim 18
Dependent Claim
20 words
The thin film acoustic resonator of claim 14, wherein said second layer of low acoustic impedance material comprises silicon dioxide.
Claim 19
Dependent Claim
33 words
The thin film acoustic resonator of claim 14, wherein said at least one pair of layers comprises a stack of alternating layers of said high and low acoustic impedance materials on said substrate.
Claim 20
Dependent Claim
37 words
The thin film acoustic resonator of claim 16, wherein each of said alternating layers of said high and low acoustic impedance materials has a thickness of 1/4 acoustic wavelength at a resonant frequency of the acoustic resonator.
Claim 21
Dependent Claim
27 words
The thin film acoustic resonator of claim 16, wherein each of said first layers of hafnium oxide is deposited by electron beam evaporation with concurrent ion bombardment.
Claim 22
Dependent Claim
21 words
The thin film acoustic resonator of claim 16, wherein each of said first layers of hafnium oxide is deposited by sputtering.
References Cited (Backward Citations)
US3767579A
Cited
US5373268A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-07 | 2001-01-06 | 2001-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-07 | 2005-01-06 | 2005-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-07 | 2009-01-06 | 2009-07-08 | $7700.00 | Window Closed / Lapsed |