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Patent US3601668A successfully refreshed from Google Patents.
US3601668A
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US
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Surface depletion layer photodevice
Assignee: Fairchild Semiconductor Corp
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Filing: 1969-11-07
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Granted: 1971-08-24
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Expires: 1989-11-07
Abstract
Abstract A semiconductor photodevice sensitive to blue light is produced by placing an oxide layer containing a selected surface state charge density over one surface of the device. The fixed surface state charge density creates a surface depletion region in the semiconductor material immediately underlying the oxide. Blue light incident on the device, which is normally absorbed before reaching the depletion region associated with a PN junction strikes the surface depletion layer and produces photocurrent therein.
Inventors
- 👤 Gary G Slaten
- 👤 Edward H Snow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:50
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/28; H10F30/282; H10F30/2823; H10F99/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
182 words
A photodevice comprising a semiconductor substrate of a first conductivity type containing a semiconductor layer of the same conductivity type formed on one surface thereof; at least one region of opposite conductivity type formed in said semiconductor layer and extending to the top surface thereof; an insulation layer overlying selected areas of said semiconductor layer, said insulation layer containing a selected fixed surface state charge Qss; wherein said insulation layer is an oxide of silicon and said fixed surface state charge density is in the range between 10 and 1013 per cm.2 and a surface depletion layer in portions of said semiconductor layer, said depletion layer being located directly under, and within 1 micron of the interface between said insulation layer and said semiconductor layer, and contacting said at least one region. metal contact layers attached to said underlying semiconductor substrate and to said at least one region of opposite conductivity, and means for reverse biasing the PN junction between said semiconductor layer, on the one hand, and said surface depletion layer and said at least one region on the other hand.
Claim 2
Dependent Claim
182 words
A photodevice comprising a semiconductor substrate of a first conductivity type containing a semiconductor layer of the same conductivity type formed on one surface thereof; at least one region of opposite conductivity type formed in said semiconductor layer and extending to the top surface thereof; an insulation layer overlying selected areas of said semiconductor layer, said insulation layer containing a selected fixed surface state charge Qss; wherein said insulation layer is an oxide of silicon and said fixed surface state charge density is in the range between 10 and 1013 per cm.2 and a surface depletion layer in portions of said semiconductor layer, said depletion layer being located directly under, and within 1 micron of the interface between said insulation layer and said semiconductor layer, and contacting said at least one region. metal contact layers attached to said underlying semiconductor substrate and to said at least one region of opposite conductivity, and means for reverse biasing the PN junction between said semiconductor layer, on the one hand, and said surface depletion layer and said at least one region on the other hand.
Claim 3
Dependent Claim
31 words
Structure as in claim 1 in which said substrate is P-type silicon, said epitaxial layer is P-type silicon, and said at least one region of opposite conductivity type comprises N-type silicon.
Claim 4
Dependent Claim
30 words
Structure as in claim 2 in which said insulation layer is an oxide of silicon and said fixed surface state charge density is at least 5 X 1012 per cm2.
Claim 5
Dependent Claim
37 words
Structure as in claim 2 including in said P-type epitaxial layer a guard ring diffused from the top surface, said guard ring containing said first type impurity to a concentration of at least 1017 atoms per cm3.
Claim 6
Dependent Claim
13 words
Structure as in claim 4 including metal contacts attached to said guard ring.
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) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |