US4539501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Epitaxial structure with increased piezoelectric effect and a surface acoustic wave electronic device comprising such a structure
Assignee: Thales SA
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Filing: 1983-12-19
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Granted: 1985-09-03
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Expires: 2003-12-19
Abstract
Abstract An epitaxial structure in which a constraint imposed by forced epitaxy causes an increase in the piezoelectric effect of a group of layers. The structure which provides this effect utilizes a semi-insulating substrate made from a first material on which is deposited by forced epitaxy a layer of a second material, the two materials are in crystalline mesh parameter disharmony, which creates in said layer a constraint increasing its piezoelectricity. On the constrained layer are deposited two groups of alternated "deforming" and "deformed" layers of the two materials. The thickness of the structure is sufficient to allow propagation of the surface waves. The advantage of this structure is that it allows two transducers such as transistors to be integrated on or at the side of this structure.
Inventors
- 👤 Linh N. Trong
- 👤 Jean Chevrier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:45
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/05; H03H9/0538; H03H9/0542; H03H9/02535; H03H9/02543; H03H9/02574; H10; H10N; H10N30/00; H10N30/80; H10N30/85; H10N30/853; H10N39/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
111 words
In an epitaxial structure with piezoelectric effect, comprising, supported by a semi-insulating substrate, a plurality of epitaxied layers, said epitaxied layers form two groups of layers, formed from two regularly alternated materials, the first material of the first group of layers having a crystalline mesh parameter equal to that of the substrate, the second material of the second group of layers having a crystalline mesh parameter different from that of the substrate and being more piezoelectric, the disharmony of the crystalline parameter between the substrate and the layers of the first group imposing on the layers of said second group a constraint deforming the crystalline network which increases the piezoelectric effect.
Claim 2
Dependent Claim
111 words
In an epitaxial structure with piezoelectric effect, comprising, supported by a semi-insulating substrate, a plurality of epitaxied layers, said epitaxied layers form two groups of layers, formed from two regularly alternated materials, the first material of the first group of layers having a crystalline mesh parameter equal to that of the substrate, the second material of the second group of layers having a crystalline mesh parameter different from that of the substrate and being more piezoelectric, the disharmony of the crystalline parameter between the substrate and the layers of the first group imposing on the layers of said second group a constraint deforming the crystalline network which increases the piezoelectric effect.
Claim 3
Dependent Claim
40 words
The epitaxial structure as claimed in claim 1, wherein the thickness of the layers under constraint of the second group is smaller than the thickness at which the crystalline network dislocations appear for a given disharmony of the mesh parameter.
Claim 4
Dependent Claim
34 words
The epitaxial structure as claimed in claim 1, wherein the thickness of the layers of said first group is at least equal to the thickness of the layers of said second group under constraint.
Claim 5
Dependent Claim
27 words
The epitaxial structure as claimed in claim 1, wherein the total thickness of the epitaxied layers is sufficient (1μ) to allow propagation of the surface acoustic waves.
Claim 6
Dependent Claim
51 words
The epitaxial structure as claimed in claim 1, wherein the pair of materials used for the substrate and the layers of said first group, on the one hand, and for the layers of said second group, on the other hand, is chosen from the compounds of the family III-V (Ga, In,As,P,Sb).
Claim 7
Dependent Claim
49 words
The epitaxial structure as claimed in claim 1, wherein the pair of materials used for the substrate and the layers of said first group, on the one hand, and for the layers of said second group on the other is chosen from the compounds of the family II-VI (Cd--Te,S).
Claim 8
Dependent Claim
49 words
The epitaxial structure as claimed in claim 1, wherein the pair of materials used for the substrate and the layers of said first group, on the one hand, and for the layers of said second group on the other, is chosen from the compounds of the family IV-VI (Pb,Te).
Claim 9
Dependent Claim
55 words
The epitaxial structure as claimed in claim 1, where it further integrates on the same substrate, in monolithic fashion, at least one electronic device formed in at least one islet of semi-conductor material deposited on the free surface of the piezoelectric structure, the electronic device being in electric contact with said structure through a metalization.
Claim 10
Dependent Claim
61 words
The epitaxial structure as claimed in claim 1, wherein it further integrates on the same substrate, in monolithic fashion, at least one electronic device formed in at least one islet of semi-conductor material deposited on the free surface of the substrate at the side of the piezoelectric structure, the electronic device being in electric contact with said structure through a metalization.
Claim 11
Dependent Claim
27 words
A surface wave acoustic electronic device, comprising at least one monolithic epitaxial structure, with increased piezoelectric effect, as claimed in any one of claims 1 to 9.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-02 | 1989-03-04 | 1989-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-02 | 1993-03-04 | 1993-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-02 | 1997-03-04 | 1997-09-03 | $7700.00 | Window Closed / Lapsed |