US4959694A
Expired / Lapsed
US
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Semiconductor heterostructures with SiGe material
Assignee: British Telecommunications PLC
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Filing: 1988-12-23
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Granted: 1990-09-25
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Expires: 2008-12-23
Abstract
Abstract A semiconductor device comprises a short-period superlattice of alternating monolayers of silicon and germanium grown on a 100 oriented SiGe substrate including 60-95% Ge. The silicon layers are M monolayers thick, and the germanium layers are N monolayers thick, where M=2(2m+1) for mδ0, 1 or 2 (preferably 0) and N=2(2n+1), n=1,2,3,4,5,6 etc. "Inhomogeneous" superlattices in which successive Ge layers have thicknesses N1, N2, N3 etc. (selected from the above N values) are disclosed.
Inventors
- 👤 Michael A. Gell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:44
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8162; H10D62/8164
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
61 words
A semiconductor device comprising a short-period superlattice of alternating layers of first and second materials of different compositions within the Si/Ge system grown epitaxially on an (100) oriented substrate, the first material layers containing substantially more silicon than the second, the first material layers being M monolayers thick, the second material layers being N monolayers thick, M being smaller than N.
Claim 2
Dependent Claim
61 words
A semiconductor device comprising a short-period superlattice of alternating layers of first and second materials of different compositions within the Si/Ge system grown epitaxially on an (100) oriented substrate, the first material layers containing substantially more silicon than the second, the first material layers being M monolayers thick, the second material layers being N monolayers thick, M being smaller than N.
Claim 3
Dependent Claim
19 words
A semiconductor device according to claim 1, wherein the first material is Silicon and the second material is Germanium.
Claim 4
Dependent Claim
29 words
A device according to claim 1 or claim 2, in which M=2(2 m+1)+x, and N=2(2 n+1)-x where x=0 or 1, m=0, 1 or 2 and n is an integer.
Claim 5
Dependent Claim
10 words
A semiconductor device as clamed in claim 3, wherein M=2.
Claim 6
Dependent Claim
12 words
A device according to claim 1 or claim 2, in which N=6.
Claim 7
Dependent Claim
10 words
A semiconductor device as claimed in claim 3 wherein 0<n<6.
Claim 8
Dependent Claim
10 words
A semiconductor device as claimed in claim 6, wherein 0<n<5.
Claim 9
Dependent Claim
19 words
A semiconductor device as claimed in claim 3, wherein n lies in the range of from 6 to 10.
Claim 10
Dependent Claim
20 words
A device according to claim 3, in which M=3 and N=(4 n+1), where n is an integer greater than 1.
Claim 11
Dependent Claim
25 words
A semiconductor device according to claim 1 further comprising a buffer layer epitaxially formed on the device substrate on which said alternating layers are grown.
Claim 12
Dependent Claim
18 words
A semiconductor device according to claim 1 or claim 10, in which the substrate consists essentially of GaAs.
Claim 13
Dependent Claim
23 words
A semiconductor device according to claims 1 or 10, in which the substrate consists essentially of Si 1-X Ge X , where 0.5<x<1.
Claim 14
Dependent Claim
9 words
A semiconductor device according to claim 12, wherein 0.6≦x<1.
Claim 15
Dependent Claim
22 words
A semiconductor device according to claim 13, wherein the ratio of M:N approximate the ratio of Silicon to Germanium in the substrate.
Claim 16
Dependent Claim
25 words
A semiconductor device according to claim 1 or claim 2, in which N values of at least some successive second material layers are not equal.
Claim 17
Dependent Claim
14 words
A semiconductor device as in claims 1 or 2 which is quasi-direct bandgap device.
Claim 18
Dependent Claim
13 words
A semiconductor device as in claim 16 which is a light emmitting device.
Claim 19
Dependent Claim
19 words
A light emitting device according to claim 17, capable of emitting light in a direction coplanar with the layers.
Claim 20
Dependent Claim
19 words
A semiconductor device as claimed in any one of claim 1 or claim 2, configured as an optical detector.
Claim 21
Dependent Claim
11 words
A semiconductor device as in claim 1 or 2 wherein M=2.
Claim 22
Dependent Claim
13 words
A semiconductor device as in claim 12 which is a quasi-direct bandgap device.
Claim 23
Dependent Claim
13 words
A semiconductor device as in claim 13 which is a quasi-direct bandgap device.
Claim 24
Dependent Claim
13 words
A semiconductor device as in claim 14 which is a quasi-direct bandgap device.
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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) | 1993-09-24 | 1994-03-26 | 1994-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-24 | 1998-03-26 | 1998-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-24 | 2002-03-26 | 2002-09-25 | $7700.00 | Window Closed / Lapsed |