US4502932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic resonator and method of making same
Assignee: United States, ENERGY THE, Secretary of, Department of
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Filing: 1983-10-13
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Granted: 1985-03-05
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Expires: 2003-10-13
Abstract
Abstract A method of fabricating an acoustic wave resonator wherein all processing steps are accomplished from a single side of said substrate. The method involves deposition of a multi-layered Al/AlN structure on a GaAs substrate followed by a series of fabrication steps to define a resonator from said composite. The resulting resonator comprises an AlN layer between two Al layers and another layer of AlN on an exterior of one of said Al layers.
Inventors
- 👤 Gerald R. Kline
- 👤 Kenneth M. Lakin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:10
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/15; H03H9/17; H03H9/171; H03H9/172; H03H9/173; H03H3/00; H03H3/007; H03H3/02; H03H3/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
177 words
A method of making an acoustic wave resonator comprising: providing a reactive sputtering system having a chamber; providing an aluminum target and a GaAs substrate in said chamber; providing an atmosphere of N 2 in said chamber and sputtering said target to deposit a first layer comprising AlN on said substrate; providing an atmosphere of Ar in said chamber and sputtering said target to deposit a second layer comprising Al; providing an atmosphere of N 2 in said chamber and sputtering said target to deposit a third layer comprising AlN; providing an atmosphere of Ar in said chamber and sputtering said target to deposit a fourth layer comprising Al, thereby forming a multi-layered composite on the GaAs substrate; defining an electrode in said fourth layer; providing a cavity in said composite to provide access to said GaAs substrate; providing an etchant for GaAs through said cavity to said substrate to etch away a portion of said GaAs substrate opposite said electrode to leave a multilayered composite shelf-like structure supported at its perphery by said remaining GaAs substrate.
Claim 2
Independent Claim
177 words
A method of making an acoustic wave resonator comprising: providing a reactive sputtering system having a chamber; providing an aluminum target and a GaAs substrate in said chamber; providing an atmosphere of N 2 in said chamber and sputtering said target to deposit a first layer comprising AlN on said substrate; providing an atmosphere of Ar in said chamber and sputtering said target to deposit a second layer comprising Al; providing an atmosphere of N 2 in said chamber and sputtering said target to deposit a third layer comprising AlN; providing an atmosphere of Ar in said chamber and sputtering said target to deposit a fourth layer comprising Al, thereby forming a multi-layered composite on the GaAs substrate; defining an electrode in said fourth layer; providing a cavity in said composite to provide access to said GaAs substrate; providing an etchant for GaAs through said cavity to said substrate to etch away a portion of said GaAs substrate opposite said electrode to leave a multilayered composite shelf-like structure supported at its perphery by said remaining GaAs substrate.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said GaAs is a crystal having (100) orientation.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein said etchant for GaAs is 1H 2 SO 4 --8H 2 O 2 --300H 2 O.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein said electrode is defined by etching away part of said fourth layer with an etchant for Al.
Claim 6
Dependent Claim
29 words
The method of claim 4 wherein said etchant for Al is selected from the group consisting of dilute HF and 4H 3 PO 4 --4CH 3 COOH--1HNO 3 solution.
Claim 7
Dependent Claim
21 words
The method of claim 1 wherein said cavity is provided by etching said composite with an etchant for Al and AlN.
Claim 8
Dependent Claim
16 words
The method of claim 6 wherein said etchant for Al and AlN is very dilute NaOH.
Claim 9
Dependent Claim
13 words
The method of claim 7 wherein oxygen is essentially excluded from said chamber.
Claim 10
Dependent Claim
19 words
The method of claim 1 wherein said substrate is maintained at a temperature of about 110° C. or less.
Claim 11
Dependent Claim
45 words
The method of claim 1 wherein an electric field is applied to said chamber during deposition of said AlN layers so that the C-axis of said layer will be substantially inclined with respect to said resonator normal, whereby said resonator will exhibit shear wave resonance.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-04 | 1988-09-03 | 1989-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-04 | 1992-09-03 | 1993-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-04 | 1996-09-03 | 1997-03-05 | $7700.00 | Window Closed / Lapsed |