US4725870A
Expired / Lapsed
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Silicon germanium photodetector
Assignee: Nokia Bell Labs
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Filing: 1985-11-18
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Granted: 1988-02-16
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Expires: 2005-11-18
Abstract
Abstract A photodetector, comprising a Ge x Si 1-x superlattice region between two silicon cladding layers in which the Ge x Si 1-x layers absorb light, is described.
Inventors
- 👤 John C. Bean
- 👤 Sergey Luryi
- 👤 Thomas P. Pearsall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:24
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/22; H10F30/222; H10F77/00; H10F77/10; H10F77/14; H10F77/146; H10F77/1465
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
66 words
A photodetector comprising a first cladding layer of silicon having a first conductivity type; an interleaved region comprising alternating layers of Ge x Si 1-x and Ge y Si 1-y , x greater than 0.0 and y and less than or equal to 1.0, y greater than or equal to 0.0 and less than than 1.0; and a second cladding layer having a second conductivity type.
Claim 2
Dependent Claim
66 words
A photodetector comprising a first cladding layer of silicon having a first conductivity type; an interleaved region comprising alternating layers of Ge x Si 1-x and Ge y Si 1-y , x greater than 0.0 and y and less than or equal to 1.0, y greater than or equal to 0.0 and less than than 1.0; and a second cladding layer having a second conductivity type.
Claim 3
Dependent Claim
15 words
A photodetector as recited in claim 1 in which said second cladding layer comprises silicon.
Claim 4
Dependent Claim
14 words
A photodetector as recited in claim 2 in which x and y are constant.
Claim 5
Dependent Claim
15 words
A photodetector as recited in claim 1 in which said first conductivity type is p-type.
Claim 6
Dependent Claim
26 words
A photodetector as recited in claim 4 further comprising a third layer of silicon having intrinsic conductivity and being between said second layer and said superlattice.
Claim 7
Dependent Claim
28 words
A photodetector as recited in claim 5 further comprising a fourth layer of silicon having a first conductivity type and being between said third layer and said superlattice.
Claim 8
Dependent Claim
17 words
A photodetector as recited in claim 1 further comprising a grating on said second layer of silicon.
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) | 1991-02-15 | 1991-08-17 | 1992-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-15 | 1995-08-17 | 1996-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-15 | 1999-08-17 | 2000-02-16 | $7700.00 | Window Closed / Lapsed |