US5059847A
Expired / Lapsed
US
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Surface acoustic wave device
Assignee: Sanyo Electric Co Ltd
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Filing: 1990-04-10
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Granted: 1991-10-22
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Expires: 2010-04-10
Abstract
Abstract A surface acoustic wave device comprising a single crystal silicon substrate and a piezoelectric thin film of single crystal or C-axis-oriented polycrystalline aluminum nitride formed on the surface of the substrate. The C-axis of the piezoelectric thin film is set in a direction in which the projection vector of the C-axis on a plane containing the axis of propagation direction of a surface acoustic wave and a normal axis of the substrate makes an inclination angle θ of up to 60 degrees with the axis of propagation direction, whereby the device is given a coupling coefficient of at least 2% is given as maximum coupling coefficient of the device.
Inventors
- 👤 Toshiharu Tanaka
- 👤 Kenichi Shibata
- 👤 Kousuke Takeuchi
- 👤 Masakazu Sakata
- 👤 Hiroshi Okano
- 👤 Kazuhiko Kuroki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:04
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/25; H03H9/02; H03H9/02535; H03H9/02543; H03H9/02574
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
134 words
A surface acoustic wave device comprising a single crystal silicon substrate and piezoelectric thin film of single crystal or C-axis-oriented polycrystalline aluminum nitride formed on the surface of the substrate, the device being characterized in that the C-axis of the piezoelectric thin film is set in a direction in which the projection vector of the C-axis on a plane containing the axis of propagation direction of a surface acoustic wave and a normal axis of the single crystal silicon substrate makes a predetermined angle of inclination θ with respect to the axis of propagation direction, the inclination angle θ is in the range of 0 degree <θ≦60 degrees, and the piezoelectric aluminum nitride thin film has a thickness h satisfying the relationship of 1.8≦2πh/λ≦20 wherein λ is the wavelength of the surface acoustic wave.
Claim 2
Dependent Claim
134 words
A surface acoustic wave device comprising a single crystal silicon substrate and piezoelectric thin film of single crystal or C-axis-oriented polycrystalline aluminum nitride formed on the surface of the substrate, the device being characterized in that the C-axis of the piezoelectric thin film is set in a direction in which the projection vector of the C-axis on a plane containing the axis of propagation direction of a surface acoustic wave and a normal axis of the single crystal silicon substrate makes a predetermined angle of inclination θ with respect to the axis of propagation direction, the inclination angle θ is in the range of 0 degree <θ≦60 degrees, and the piezoelectric aluminum nitride thin film has a thickness h satisfying the relationship of 1.8≦2πh/λ≦20 wherein λ is the wavelength of the surface acoustic wave.
Claim 3
Dependent Claim
33 words
A surface acoustic wave device as defined in claim 1 wherein the piezoelectric thin film forming surface of the single crystal silicon substrate is the (001) crystal plane or a plane equivalent thereto.
Claim 4
Dependent Claim
26 words
A surface acoustic wave device as defined in claim 2 wherein the C-axis of the piezoelectric aluminum nitride thin film is set in the projection plane.
Claim 5
Dependent Claim
28 words
A surface acoustic wave device as defined in claim 3 wherein the axis of propagation direction is set to the [100] axis of the single crystal silicon substrate.
Claim 6
Dependent Claim
33 words
A surface acoustic wave device as defined in claim 1 wherein the piezoelectric thin film forming surface of the single crystal silicon substrate is the (110) crystal plane or a plane equivalent thereto.
Claim 7
Dependent Claim
26 words
A surface acoustic wave device as defined in claim 5 wherein the C-axis of the piezoelectric aluminum nitride thin film is set in the projection plane.
Claim 8
Dependent Claim
28 words
A surface acoustic wave device as defined in claim 6 wherein the axis of propagation direction is set to the [001] axis of the single crystal silicon substrate.
Claim 9
Dependent Claim
33 words
A surface acoustic wave device as defined in claim 1 wherein the piezoelectric thin film forming surface of the single crystal silicon substrate is the (111) crystal plane or a plane equivalent thereto.
Claim 10
Dependent Claim
65 words
A surface acoustic wave device as defined in claim 8 wherein the C-axis of the piezoelectric aluminum nitride thin film is set in the projection plane, and the inclination angle θ is in the range of 20 degrees ≦θ≦60 degrees, the piezoelectric aluminum nitride thin film having a thickness h satisfying the relationship of 2.5≦2πh/λ≦20 wherein λ is the wavelength of the surface acoustic wave.
Claim 11
Dependent Claim
28 words
A surface acoustic wave device as defined in claim 9 wherein the axis of propagation direction is set to the [112] axis of the single crystal silicon substrate.
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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) | 1994-10-21 | 1995-04-22 | 1995-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-21 | 1999-04-22 | 1999-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-21 | 2003-04-22 | 2003-10-22 | $7700.00 | Window Closed / Lapsed |