US3767983A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Charge transfer device with improved transfer efficiency
Assignee: AT&T Inc
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Filing: 1972-08-23
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Granted: 1973-10-23
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Expires: 1992-08-23
Abstract
Abstract The transfer efficiency of a bucket-brigade charge transfer device is improved by adapting the transfer regions between successive storage sites such that in each transfer region at least two distinct threshold voltages occur, with the greater threshold voltage being in the trailing portion of the transfer zone with respect to the direction of advance of information. Advantageously, the differences in threshold voltage in each transfer region are realized through differences in oxide thickness or differences in the doping of the transfer region.
Inventors
- 👤 C Berglund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:48
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/18; G11C19/182; G11C19/184; G11C19/186; H; H10; H10D; H10D84/00; H10D84/891; H10D84/895
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
153 words
In a bucket-brigade charge transfer apparatus of the type including: a storage medium having a major surface; a plurality of spaced localized zones of immobile charge disposed in a path along the surface; an insulating layer disposed over the surface and the zones; and a plurality of localized electrodes disposed over the dielectric and registered with the localized zones such that separate ones of said electrodes extend over the space between a separate pair of successive zones and over one zone of said pair more than the other zone of said pair, the improvement which comprises: separate means associated with each space between a pair of successive zones for causing in said space a plurality of different distinct threshold voltages, with said threshold voltages decreasing from the trailing portion to the leading portion of said space, said means including means for causing a substantially abrupt transition between successive ones of said threshold voltages.
Claim 2
Dependent Claim
153 words
In a bucket-brigade charge transfer apparatus of the type including: a storage medium having a major surface; a plurality of spaced localized zones of immobile charge disposed in a path along the surface; an insulating layer disposed over the surface and the zones; and a plurality of localized electrodes disposed over the dielectric and registered with the localized zones such that separate ones of said electrodes extend over the space between a separate pair of successive zones and over one zone of said pair more than the other zone of said pair, the improvement which comprises: separate means associated with each space between a pair of successive zones for causing in said space a plurality of different distinct threshold voltages, with said threshold voltages decreasing from the trailing portion to the leading portion of said space, said means including means for causing a substantially abrupt transition between successive ones of said threshold voltages.
Claim 3
Dependent Claim
24 words
Apparatus as recited in claim 1 wherein said plurality is two, with the greater threshold voltage being in a trailing portion of the space.
Claim 4
Dependent Claim
150 words
In bucket-brigade charge transfer apparatus of the type including: a storage medium having a major surface; a plurality of spaced, localized zones of immobile charge disposed in a path along the surface; an insulating layer disposed over the surface and the zones; and a plurality of localized electrodes disposed over the dielectric and registered with the localized zones such that separate ones of said electrodes extend over the space between a separate pair of successive zones and over one zone of said pair more than the other zone of said pair, the improvement which comprises: means associated with each space between a pair of successive zones for causing in the trailing portion of said space a firsT uniform threshold voltage greater than a second uniform threshold voltage in the leading portion of said space and for further causing a substantially abrupt transition between the two regions of differing threshold voltages.
Claim 5
Dependent Claim
150 words
In bucket-brigade charge transfer apparatus of the type including: a storage medium having a major surface; a plurality of spaced, localized zones of immobile charge disposed in a path along the surface; an insulating layer disposed over the surface and the zones; and a plurality of localized electrodes disposed over the dielectric and registered with the localized zones such that separate ones of said electrodes extend over the space between a separate pair of successive zones and over one zone of said pair more than the other zone of said pair, the improvement which comprises: means associated with each space between a pair of successive zones for causing in the trailing portion of said space a firsT uniform threshold voltage greater than a second uniform threshold voltage in the leading portion of said space and for further causing a substantially abrupt transition between the two regions of differing threshold voltages.
Claim 6
Dependent Claim
37 words
Apparatus as recited in claim 3 wherein the means for causing the differing threshold voltages includes in the trailing portion of said space a thicker insulating portion than is disposed over the leading portion of said space.
Claim 7
Dependent Claim
43 words
Apparatus as recited in claim 3 wherein the means for causing the differing threshold voltages includes in the trailing portion of said space a greater concentration of dopant impurities in the storage medium than are disposed in the leading portion of said space.
Claim 8
Dependent Claim
53 words
Apparatus as recited in claim 3 including means for applying to the plurality of localized electrodes two-phase voltages of magnitude and polarity sufficient for causing advance of information but insufficient for causing a depletion region to extend from a localized zone halfway across the space between said zone and the zone next preceding.
Claim 9
Dependent Claim
49 words
Apparatus as recited in claim 6 wherein the means for applying said voltages includes a pair of conduction paths, every second electrode being connected to a common one of said conduction paths and the remaining electrodes being connected in common to the other of said pair of conduction paths.
Claim 10
Dependent Claim
16 words
Apparatus as recited in claim 7 wherein the two-phase voltages are applied to the conduction paths.
Claim 11
Dependent Claim
22 words
Apparatus as recited in claim 3 wherein the storage medium is a silicon semiconductive material and the insulating layer includes silicon oxide.
References Cited (Backward Citations)
US3651349A
Cited
US3697786A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |