US4516049A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-layer acoustic surface wave device having minimal delay time temperature coefficient
Assignee: Faurecia Clarion Electronics Co Ltd
•
Filing: 1983-09-28
•
Granted: 1985-05-07
•
Expires: 2003-09-28
Abstract
Abstract An acoustic surface wave device includes a substrate made of an elastic material, a multilayer structure disposed on a surface of the substrate and having a silicon dioxide layer and an aluminum nitride layer superimposed on each other, and electrodes having predetermined configurations formed on the multilayer structure. The main component of the elastic material is a silicon monocrystal, whose temperature coefficient of delay time for acoustic surface waves is positive, and the piezo-electric axis of the aluminum nitride is either perpendicular or parallel to the surface of the substrate, with a negative delay coefficient, counteracting that of the substrate.
Inventors
- 👤 Nobuo Mikoshiba
- 👤 Kazuo Tsubouchi
- 👤 Kazuyoshi Sugai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:29
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02834; H03H9/02543; H03H9/02574
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
156 words
Acoustic surface wave device comprising: a substrate made of an elastic material having a silicon monocrystal, said silicon monocrystal having a temperature coefficient of delay time for acoustic surface waves which is positive; a multilayer structure which is disposed on a surface of said substrate and includes a silicon dioxide layer and an aluminum nitride layer, said aluminum nitride layer being formed on said silicon dioxide layer so that a piezoelectric axis of said aluminum nitride layer has a predetermined orientation, said silicon dioxide layer and said aluminum nitride layer each having a temperature coefficient of delay time for acoustic surface waves which is negative, said negative temperature coefficients being substantially equal to and substantially counteracting the effects of said positive temperature coefficient of said substrate; and first electrode means for generating and second electrode means for detecting acoustic surface waves, said first and second electrode means being formed at predetermined positions on said multilayer structure.
Claim 2
Dependent Claim
156 words
Acoustic surface wave device comprising: a substrate made of an elastic material having a silicon monocrystal, said silicon monocrystal having a temperature coefficient of delay time for acoustic surface waves which is positive; a multilayer structure which is disposed on a surface of said substrate and includes a silicon dioxide layer and an aluminum nitride layer, said aluminum nitride layer being formed on said silicon dioxide layer so that a piezoelectric axis of said aluminum nitride layer has a predetermined orientation, said silicon dioxide layer and said aluminum nitride layer each having a temperature coefficient of delay time for acoustic surface waves which is negative, said negative temperature coefficients being substantially equal to and substantially counteracting the effects of said positive temperature coefficient of said substrate; and first electrode means for generating and second electrode means for detecting acoustic surface waves, said first and second electrode means being formed at predetermined positions on said multilayer structure.
Claim 3
Dependent Claim
19 words
Acoustic surface wave device according to claim 1, wherein said elastic material of said substrate is a silicon monocrystal.
Claim 4
Dependent Claim
70 words
Acoustic surface wave device according to claim 2, wherein said surface of said substrate is a crystallographical surface, said piezoelectric axis of said aluminum nitride layer is perpendicular to said surface, said silicon dioxide layer is disposed on said surface of said silicon monocrystal substrate, and said first electrode means propagates acoustic surface waves in a direction perpendicular to the direction of said piezoelectric axis of said aluminum nitride layer.
Claim 5
Dependent Claim
44 words
Acoustic surface wave device according to claim 3, wherein said crystallographical surface is equivalent to (111), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<3.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 6
Dependent Claim
44 words
Acoustic surface wave device according to claim 3, wherein said crystallographical surface is equivalent to (110), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 7
Dependent Claim
44 words
Acoustic surface wave device according to claim 3, wherein said crystallographical surface is equivalent to (100), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 8
Dependent Claim
70 words
Acoustic surface wave device according to claim 2, wherein said surface of said substrate is a crystallographical surface, said piezoelectric axis of said aluminum nitride layer is perpendicular to said surface, said silicon dioxide layer is disposed on said surface of said silicon monocrystal substrate, and said first electrode means propagates acoustic surface waves in a direction parallel to the direction of said piezoelectric axis of said aluminum nitride layer.
Claim 9
Dependent Claim
44 words
Acoustic surface wave device according to claim 7, wherein said crystallographical surface is equivalent to (111), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<3.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 10
Dependent Claim
44 words
Acoustic surface wave device according to claim 7, wherein said crystallographical surface is equivalent to (110), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 11
Dependent Claim
44 words
Acoustic surface wave device according to claim 7, wherein said crystallographical surface is equivalent to (100), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 12
Dependent Claim
70 words
Acoustic surface wave device according to claim 2, wherein said surface of said substrate is a crystallographical surface, said piezoelectric axis of said aluminum nitride layer is parallel to said surface, said silicon dioxide layer is disposed on said surface of said silicon monocrystal substrate, and said first electrode means propagates acoustic surface waves in a direction perpendicular to the direction of said piezoelectric axis of said aluminum nitride layer.
Claim 13
Dependent Claim
44 words
Acoustic surface wave device according to claim 11, wherein said crystallographical surface is equivalent to (111), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<3.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 14
Dependent Claim
44 words
Acoustic surface wave device according to claim 11, wherein said crystallographical surface is equivalent to (110), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 15
Dependent Claim
44 words
Acoustic surface wave device according to claim 11, wherein said crystallographical surface is equivalent to (100), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 16
Dependent Claim
70 words
Acoustic surface wave device according to claim 2, wherein said surface of said substrate is a crystallographical surface, said piezoelectric axis of said aluminum nitride layer is parallel to said surface, said silicon dioxide layer is disposed on said surface of said silicon monocrystal substrate, and said first electrode means propagates acoustic surface waves in a direction parallel to the direction of said piezoelectric axis of said aluminum nitride layer.
Claim 17
Dependent Claim
44 words
Acoustic surface wave device according to claim 15, wherein said crystallographical surface is equivalent to (111), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<3.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 18
Dependent Claim
44 words
Acoustic surface wave device according to claim 15, wherein said crystallographical surface is equivalent to (110), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 19
Dependent Claim
44 words
Acoustic surface wave device according to claim 15, wherein said crystallographical surface is equivalent to (100), and wherein said aluminum nitride layer has a thickness H which is in a range defined by 2πH/λ<6.0, where λ denotes the wavelength of the acoustic surface waves.
Claim 20
Dependent Claim
25 words
Acoustic surface wave device according to claim 1, wherein said first and second electrode means are provided between said silicon dioxide and aluminum nitride layers.
Claim 21
Dependent Claim
38 words
Acoustic surface wave device according to claim 19, including first and second shielding electrodes which are provided on a side of said aluminum nitride layer opposite from and are respectively aligned with said first and second electrode means.
Claim 22
Dependent Claim
31 words
Acoustic surface wave device according to claim 1, wherein said first and second electrode means are provided on a side of said aluminum nitride layer remote from said silicon dioxide layer.
Claim 23
Dependent Claim
33 words
Acoustic surface wave device according to claim 21, including first and second shielding electrodes provided between said aluminum nitride and silicon dioxide layers and respectively aligned with said first and second electrode means.
References Cited (Backward Citations)
GB1363519A
Cited
US3956647A
Cited
US3965444A
Cited
US4038615A
Cited
US4037176A
Cited
US4194171A
Cited
US4393321A
Cited
US4358745A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-06 | 1988-11-05 | 1989-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-06 | 1992-11-05 | 1993-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-06 | 1996-11-05 | 1997-05-07 | $7700.00 | Window Closed / Lapsed |