US4843439A
Expired / Lapsed
US
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Tailorable infrared sensing device with strain layer superlattice structure
Assignee: National Aeronautics and Space Administration
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Filing: 1987-11-25
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Granted: 1989-06-27
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Expires: 2007-11-25
Abstract
Abstract An infrared photodetector is formed of a heavily doped p-type Ge x Si 1-x /Si superlattice in which x is pre-established during manufacture in the range 0 to 100 percent. A custom tailored photodetector that can differentiate among close wavelengths in the range of 2.7 to 50 microns is fabricated by appropriate selection of the alloy constituency value, x, to establish a specific wavelength at which photodetection cut-off will occur.
Inventors
- 👤 Li-Jen Cheng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:30
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F39/00; H10F39/10; H10F39/103; H10F77/00; H10F77/10; H10F77/14; H10F77/146; H10F77/1465
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
46 words
An infrared photodetector comprising; a silicon substrate; a Ge x Si 1-x /Si first supperlattice formed on said silicon substrate, where 0<x≦1.00, Ge x Si 1-x layers of the first superlattice are doped with a p-type impurity, and Si layers of the first superlattice are intrinsic.
Claim 2
Dependent Claim
46 words
An infrared photodetector comprising; a silicon substrate; a Ge x Si 1-x /Si first supperlattice formed on said silicon substrate, where 0<x≦1.00, Ge x Si 1-x layers of the first superlattice are doped with a p-type impurity, and Si layers of the first superlattice are intrinsic.
Claim 3
Dependent Claim
16 words
An infrared photodetector according to claim 1 wherein x is in the range 0 to 0.50.
Claim 4
Dependent Claim
25 words
An infrared photodetector according to claim 1 further comprising signal processing means formed on said silicon substrate for processing photodetection signals developed by said superlattice.
Claim 5
Dependent Claim
26 words
An infrared photodetector according to claim 1 wherein a portion of the silicon substrate, underlying the first superlattice, is doped to have a p-type conductivity characteristic.
Claim 6
Dependent Claim
56 words
An infrared photodetector according to claim 4 further comprising a radiation window layer disposed above the first superlattice so as to sandwich the first superlattice between the radiation window layer and the substrate, where the radiation window layer is thicker than at least one of the layers of the first superlattice and includes a p-type semiconductor.
Claim 7
Dependent Claim
52 words
An infrared photodetector according to claim 1 further comprising a Ge x' Si 1-x' /Si second superlattice formed on the substrate, where 0<x'≦1.00, x' is different from x, Ge x' Si 1-x' layers of the second superlattice are doped with a p-type impurity, and Si layers of the second superlattice are intrinsic.
Claim 8
Dependent Claim
20 words
An infrared photodetector according to claim 6 wherein the first superlattice is sandwiched between the substrate and the second superlattice.
Claim 9
Dependent Claim
25 words
An infrared photodetector according to claim 6 wherein the first and second superlattices are positioned side by side next to one another on the substrate.
Claim 10
Dependent Claim
30 words
An infrared photodetector according to claim 6 further comprising current flow detection means, coupled to the first and second superlattices for detecting current flow through the first and second superlattices.
Claim 11
Dependent Claim
27 words
An infrared photodetector according to claim 1 further comprising current flow detection means, coupled to the first and superlattice for detecting current flow through the first superlattice.
Claim 12
Dependent Claim
91 words
A photodetector circuit comprising: a semiconductor substrate; a superlattice, grown on said substrate, including a herterojunction layer composed of a p-doped semiconductive alloy of the general ternary form (A x B 1-x ) y C 1-y , where A x B 1-x is a binary semiconductive alloy, C is a band gap altering material for altering the band gap of the binary alloy A x B 1-x , y is equal to or greater than 0.95, and C is substantially soluble in the binary allow A x B 1-x for y≧0.95.
Claim 13
Dependent Claim
91 words
A photodetector circuit comprising: a semiconductor substrate; a superlattice, grown on said substrate, including a herterojunction layer composed of a p-doped semiconductive alloy of the general ternary form (A x B 1-x ) y C 1-y , where A x B 1-x is a binary semiconductive alloy, C is a band gap altering material for altering the band gap of the binary alloy A x B 1-x , y is equal to or greater than 0.95, and C is substantially soluble in the binary allow A x B 1-x for y≧0.95.
Claim 14
Dependent Claim
17 words
A photodetector according to claim 11 wherein A is germanium, B is silicon and C is tin.
Claim 15
Dependent Claim
38 words
A photodetector comprising: a first superlattice having one or more Ge x Si 1-x /Si heterojunctions wherein the Ge x Si 1-x side of each heterojunction is doped with a p-type impurity and the Si side is intrinsic.
Claim 16
Dependent Claim
38 words
A photodetector comprising: a first superlattice having one or more Ge x Si 1-x /Si heterojunctions wherein the Ge x Si 1-x side of each heterojunction is doped with a p-type impurity and the Si side is intrinsic.
Claim 17
Dependent Claim
27 words
A photodetector according to claim 13 further including A second superlattice having one or more Ge x' Si 1-x' /Si heterojunctions wherein x' is different from x.
Claim 18
Dependent Claim
46 words
A photodetector comprising: a superlattice having one or more (Ge x Si 1-x ) y Sn 1-y /Si heterojunctions wherein y≧0.95, the (Ge x Si 1-x ) y Sn 1-y side of each heterojunction is doped with a p-type impurity, and the Si side is intrinsic.
Claim 19
Dependent Claim
46 words
A photodetector comprising: a superlattice having one or more (Ge x Si 1-x ) y Sn 1-y /Si heterojunctions wherein y≧0.95, the (Ge x Si 1-x ) y Sn 1-y side of each heterojunction is doped with a p-type impurity, and the Si side is intrinsic.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |