Patent US4809048A successfully refreshed from Google Patents.
US4809048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Charge-coupled device having channel region with alternately changing potential in a direction perpendicular to charge transfer
Assignee: Mitsubishi Electric Corp
•
Filing: 1987-02-09
•
Granted: 1989-02-28
•
Expires: 2007-02-09
Abstract
Abstract A charge-coupled device comprises a p type silicon substrate (130), a plurality of n type impurity regions (121) of a high impurity concentration, a plurality of n type impurity regions (140) of a low impurity concentration, a silicon oxide film (150) for defining a channel region (10), a gate oxide film (110), a plurality of gate electrodes (21, 31, 41, 51, 22, 32, 42 and 52) and clock bus lines (70, 80, 90 and 100) for applying a clock signal to the respective gate electrodes. The n type impurity regions (121) and (140) are formed alternately in the channel region (10) along a direction perpendicular to the charge transfer direction, whereby the potential in the channel region (10) changes in the above described perpendicular direction. The change of the potential causes a strong electric field in the channel region (10) in the above described perpendicular direction, which serves to prevent carriers from freezing to an impurity level at a low temperature. Thus, the transfer efficiency of carriers is improved.
Inventors
- 👤 Masafumi Kimata
- 👤 Natsuro Tsubouchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:33
CPC Classifications
H; H10; H10D; H10D44/00; H10D44/40; H10D44/45; H10D44/462; H10D44/468; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/335
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
169 words
A charge-coupled device having improved low temperature charge transfer efficiency, comprising: a semiconductor substrate (130) of a first conductivity type, a channel separation insulation layer (150) formed on said semiconductor substrate (130) and having an opening to define a channel region (10) in said substrate for transferring signal charge, said channel region being contiguous and of a second conductivity type opposite said first conductivity type and formed to have, in operation, a first potential that alternates repetitively between a high and a low value throughout said channel region perpendicular to a direction in which signal charge is transferred, said first potential alternating within a range that is deeper than a second potential in said semiconductor substrate below said channel separation layer (150) to reduce charge trapping in said channel region, a gate insulating film (110) formed on said channel region (10), and a plurality of gate electrodes (21, 31 . . . 52) formed at intervals on said gate insulating film (110) in the direction of signal charge transfer.
Claim 2
Dependent Claim
169 words
A charge-coupled device having improved low temperature charge transfer efficiency, comprising: a semiconductor substrate (130) of a first conductivity type, a channel separation insulation layer (150) formed on said semiconductor substrate (130) and having an opening to define a channel region (10) in said substrate for transferring signal charge, said channel region being contiguous and of a second conductivity type opposite said first conductivity type and formed to have, in operation, a first potential that alternates repetitively between a high and a low value throughout said channel region perpendicular to a direction in which signal charge is transferred, said first potential alternating within a range that is deeper than a second potential in said semiconductor substrate below said channel separation layer (150) to reduce charge trapping in said channel region, a gate insulating film (110) formed on said channel region (10), and a plurality of gate electrodes (21, 31 . . . 52) formed at intervals on said gate insulating film (110) in the direction of signal charge transfer.
Claim 3
Dependent Claim
30 words
A charge-coupled device in accordance with claim 1, wherein: the impurity concentration of said channel region changes along a direction perpendicular to the direction in which a charge is transferred.
Claim 4
Dependent Claim
61 words
A charge-coupled device in accordance with claim 2, wherein: the impurity concentration of said channel region changes by steps as a result of forming a plurality of channel regions of a high impurity concentration (121) and a plurality of channel regions of a low impurity concentration formed alternately along the direction perpendicular to the direction in which a charge is transferred.
Claim 5
Dependent Claim
47 words
A charge-coupled device in accordance with claim 3, wherein: said plurality of channel regions of a high impurity concentration and said plurality of channel regions of a low impurity concentration respectively extend parallel to the direction in which a charge is transferred and respectively have uniform widths.
Claim 6
Dependent Claim
30 words
A charge-coupled device in accordance with claim 1, wherein: the thickness of said gate insulating film changes along the direction perpendicular to the direction in which a charge is transferred.
Claim 7
Dependent Claim
54 words
A charge-coupled device in accordance with claim 5, wherein: the thickness of said gate insulating film changes by steps as a result of forming a plurality of thick gate insulating films and a plurality of thin gate insulating films formed alternately along the direction perpendicular to the direction in which a charge is transferred.
Claim 8
Dependent Claim
41 words
A charge-coupled device in accordance with claim 6, wherein: said plurality of thick gate insulating films and said plurality of thin gate insulating films respectively extend parallel to the direction in which a charge is transferred and respectively have uniform widths.
Claim 9
Dependent Claim
19 words
A charge-coupled device in accordance with claim 1, wherein: said plurality of gate electrodes are driven by four phases.
Claim 10
Dependent Claim
36 words
A charge-coupled device in accordance with claim 1, wherein: the impurity concentration of said semiconductor region of the second conductive type is higher than the impurity concentration of said semiconductor substrate of the first conductive type.
Claim 11
Dependent Claim
176 words
A charge coupled device having improved low temperature charge transfer efficiency, comprising: a semiconductor substrate (130) of a first conductivity type; a channel separation insulation layer (150) formed on said semiconductor substrate and having an opening to define a channel region in said substrate for transferring signal charge, said channel region being contiguous and of a second conductivity type opposite said first conductivity type, wherein the impurity concentration of said channel region changes along a direction perpendicular to the direction of signal charge transfer so that the channel region has, in operation, a first potential that alternates repetitively between a high and a low value throughout said channel region perpendicular to said signal charge transfer direction, said first potential alternating within a range that is deeper than a second potential in said semiconductor substrate below said channel separation layer; a gate insulating film (110) formed on said channel region; and a plurality of gate electrodes (21), (31) . . . (52) formed at intervals on said gate insulating film in the direction of signal charge transfer.
Claim 12
Dependent Claim
176 words
A charge coupled device having improved low temperature charge transfer efficiency, comprising: a semiconductor substrate (130) of a first conductivity type; a channel separation insulation layer (150) formed on said semiconductor substrate and having an opening to define a channel region in said substrate for transferring signal charge, said channel region being contiguous and of a second conductivity type opposite said first conductivity type, wherein the impurity concentration of said channel region changes along a direction perpendicular to the direction of signal charge transfer so that the channel region has, in operation, a first potential that alternates repetitively between a high and a low value throughout said channel region perpendicular to said signal charge transfer direction, said first potential alternating within a range that is deeper than a second potential in said semiconductor substrate below said channel separation layer; a gate insulating film (110) formed on said channel region; and a plurality of gate electrodes (21), (31) . . . (52) formed at intervals on said gate insulating film in the direction of signal charge transfer.
Claim 13
Dependent Claim
168 words
A charge-coupled device having improved low temperature charge transfer efficiency, comprising: a semiconductor substrate (130) of a first conductivity type; a channel separation insulation layer (150) formed on said semiconductor substrate and having an opening to define a channel region (10) in said substrate for transferring signal charge, said channel region being contiguous and of a second conductivity type opposite said first conductivity type and formed to have, in operation, a first potential that alternates repetitively between a high and a low value throughout said channel region perpendicular to the direction of signal charge transfer, said first potential alternating within a range that is deeper than a second potential in said semiconductor substrate below said channel separation layer; a gate insulating film (110) having a thickness less than the thickness of said channel separation insulating layer formed on said channel region; and a plurality of gate electrodes (21), (31) . . . (52) formed at intervals on said gate insulating film in the direction of signal charge transfer.
Claim 14
Dependent Claim
168 words
A charge-coupled device having improved low temperature charge transfer efficiency, comprising: a semiconductor substrate (130) of a first conductivity type; a channel separation insulation layer (150) formed on said semiconductor substrate and having an opening to define a channel region (10) in said substrate for transferring signal charge, said channel region being contiguous and of a second conductivity type opposite said first conductivity type and formed to have, in operation, a first potential that alternates repetitively between a high and a low value throughout said channel region perpendicular to the direction of signal charge transfer, said first potential alternating within a range that is deeper than a second potential in said semiconductor substrate below said channel separation layer; a gate insulating film (110) having a thickness less than the thickness of said channel separation insulating layer formed on said channel region; and a plurality of gate electrodes (21), (31) . . . (52) formed at intervals on said gate insulating film in the direction of signal charge transfer.
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) | 1992-02-28 | 1992-08-29 | 1993-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-28 | 1996-08-29 | 1997-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-28 | 2000-08-29 | 2001-02-28 | $7700.00 | Window Closed / Lapsed |