US3675140A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic wave amplifier having a coupled semiconductor layer
Assignee: International Business Machines Corp
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Filing: 1970-06-30
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Granted: 1972-07-04
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Expires: 1990-06-30
Abstract
Abstract An amplifier for Rayleigh surface acoustic waves in which an additional control is provided. A region of variable conductivity is located in close proximity to the surface on which the acoustic wave travels. Examples of this region are an inversion layer whose conductivity is controlled by electrical bias, and a bulk region whose conductivity is controlled by a variable width depletion region. The electric field produced by moving charge carriers in the variable conductivity region interacts with the piezoelectric field produced by the acoustic wave to transfer energy to the acoustic wave, or extract energy from this wave.
Inventors
- 👤 Frank F Fang
- 👤 Eric G Lean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:33
CPC Classifications
H; H03; H03F; H03F13/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
134 words
A device for surface acoustic waves comprising: a piezoelectric medium capable of supporting a surface acoustic wave; means for generating said acoustic wave in said piezoelectric medium; a region in which charge carriers exist, said region being sufficiently close to said piezoelectric medium that the electric field associated with said charge carriers interacts with the electric field associated with said acoustic wave, said interaction causing amplification of said acoustic wave depending on the relative velocity of said charge carriers and said acoustic wave; means for accelerating said charge carriers in said region for adjustment of said relative veloCity to produce amplification of said acoustic wave; means for varying the number of charge carriers in said region to vary said amplification; and means for detecting said acoustic wave after said interaction with said charge carriers.
Claim 2
Independent Claim
134 words
A device for surface acoustic waves comprising: a piezoelectric medium capable of supporting a surface acoustic wave; means for generating said acoustic wave in said piezoelectric medium; a region in which charge carriers exist, said region being sufficiently close to said piezoelectric medium that the electric field associated with said charge carriers interacts with the electric field associated with said acoustic wave, said interaction causing amplification of said acoustic wave depending on the relative velocity of said charge carriers and said acoustic wave; means for accelerating said charge carriers in said region for adjustment of said relative veloCity to produce amplification of said acoustic wave; means for varying the number of charge carriers in said region to vary said amplification; and means for detecting said acoustic wave after said interaction with said charge carriers.
Claim 3
Dependent Claim
13 words
The device of claim 1, where said region comprises a Schottky barrier diode.
Claim 4
Dependent Claim
28 words
The device of claim 1, where said region comprises a semiconductor having a layer close to said piezoelectric medium in which the number of charge carriers is variable.
Claim 5
Dependent Claim
16 words
The device of claim 3, where said layer includes an inversion layer whose conductivity is variable.
Claim 6
Dependent Claim
36 words
The device of claim 3, where said layer includes a p-n junction having a depletion layer associated therewith, the width of said depletion layer being dependent on said means for varying the number of charge carriers.
Claim 7
Dependent Claim
19 words
The device of claim 1, where said means for varying the number of charge carriers is an electrical means.
Claim 8
Dependent Claim
14 words
The device of claim 6, where said electrical means is a variable AC source.
Claim 9
Dependent Claim
13 words
The device of claim 1, where said region comprises a metal-semiconductor rectifying contact.
Claim 10
Dependent Claim
12 words
The device of claim 1, where said piezoelectric medium is a semiconductor.
Claim 11
Independent Claim
134 words
A device for surface acoustic waves, comprising: a piezoelectric medium capable of supporting a surface acoustic wave on one surface thereof; means for generating said surface acoustic wave on said piezoelectric medium and for detecting said surface acoustic waves; a second medium adjacent said surface, said second medium having a region therein which is in close proximity to said surface; means for accelerating charge carriers in said region, said accelerating carriers interacting with said surface acoustic wave to provide amplification of said acoustic wave when the velocity of said carriers is greater than the velocity of said acoustic wave; means for changing the number of charge carriers in said region to vary said amplification of acoustic waves in said device; and means for detecting said surface acoustic waves after interaction with said charge carriers.
Claim 12
Independent Claim
134 words
A device for surface acoustic waves, comprising: a piezoelectric medium capable of supporting a surface acoustic wave on one surface thereof; means for generating said surface acoustic wave on said piezoelectric medium and for detecting said surface acoustic waves; a second medium adjacent said surface, said second medium having a region therein which is in close proximity to said surface; means for accelerating charge carriers in said region, said accelerating carriers interacting with said surface acoustic wave to provide amplification of said acoustic wave when the velocity of said carriers is greater than the velocity of said acoustic wave; means for changing the number of charge carriers in said region to vary said amplification of acoustic waves in said device; and means for detecting said surface acoustic waves after interaction with said charge carriers.
Claim 13
Dependent Claim
37 words
The device of claim 10, wherein said piezoelectric medium and said second medium are comprised of semiconductors, said piezoelectric medium and said second medium being in physical contact at the surface on which said acoustic wave travels.
Claim 14
Dependent Claim
12 words
The device of claim 10, where said region is an inversion layer.
Claim 15
Dependent Claim
28 words
The device of claim 10, where said region includes a semiconductor layer having a P-N junction therein, the depletion layer associated with said junction being variable in width.
Claim 16
Dependent Claim
32 words
The device of claim 10, where said second medium comprises a metal-semiconductor rectifying contact, said semiconductor being in contact with the surface of said piezoelectric medium on which said acoustic wave travels.
Claim 17
Dependent Claim
13 words
The device of claim 19 where said region comprises a Schottky barrier diode.
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) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |