US5221413A
Expired / Lapsed
US
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Method for making low defect density semiconductor heterostructure and devices made thereby
Assignee: Nokia Bell Labs
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Filing: 1991-04-24
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Granted: 1993-06-22
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Expires: 2011-04-24
Abstract
Abstract The present invention is predicated upon the discovery by applicants that by growing germanium-silicon alloy at high temperatures in excess of about 850° C. and increasing the germanium content at a gradient of less than about 25% per micrometer, one can grow on silicon large area heterostructures of graded Ge x Si 1-x alloy having a low level of threading dislocation defects. With low concentrations of germanium 0.10≦×≦0.50), the heterolayer can be used as a substrate for growing strained layer silicon devices such as MODFETS. With high concentrations of Ge (0.65≦×≦1.00) the heterolayer can be used on silicon substrates as a buffer layer for indium gallium phosphide devices such as light emitting diodes and lasers. At concentrations of pure germanium (X=1.00), the heterolayer can be used for GaAs or GaAs/AlGaAs devices.
Inventors
- 👤 Daniel Brasen
- 👤 Eugene A. Fitzgerald, Jr.
- 👤 Martin L. Green
- 👤 Ya-Hong Xie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:56
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/01; H10H20/011; H10H20/013; H10H20/0133; H10D; H10D30/00; H10D30/01; H10D30/015; H10D84/00; H10D84/01; H10D84/02; H10D84/08; H10H29/00; H10H29/10; H10P; H10P14/00; H10P14/20; H10P14/22; H10P14/24; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/32; H10P14/3202; H10P14/3204; H10P14/3211; H10P14/3242; H10P14/3244; H10P14/3254; H10P14/34; H10P14/3402; H10P14/3414; H10P14/3418; H10P14/3421; H10D62/00; H10D62/80; H10D62/82; H10D62/822; H10H20/80; H10H20/83; H10H20/831; H10H20/8314; Y; Y10; Y10S; Y10S438/00; Y10S438/938
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
78 words
A method for making a semiconductor device comprising the steps of: providing a monocrystalline silicon substrate; epitaxially growing on said silicon substrate at a temperature in excess of 850° C. a graded layer of Ge x Si l-x with increasing germanium content at a gradient of less than about 25% per micrometer to a final composition in the range 0.1≦x≦1.0; and epitaxially growing a layer of semiconductor material above said graded layer of Ge x Si l-x .
Claim 2
Independent Claim
78 words
A method for making a semiconductor device comprising the steps of: providing a monocrystalline silicon substrate; epitaxially growing on said silicon substrate at a temperature in excess of 850° C. a graded layer of Ge x Si l-x with increasing germanium content at a gradient of less than about 25% per micrometer to a final composition in the range 0.1≦x≦1.0; and epitaxially growing a layer of semiconductor material above said graded layer of Ge x Si l-x .
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein said layer of semiconductor material comprises a cap layer of Ge--Si alloy having the same composition as the surface of the graded layer and a thickness in excess of 100 angstroms.
Claim 4
Dependent Claim
30 words
The method of claim 1 wherein said graded layer of Ge x Si l-x has a final composition in the range 0.1≦x≦0.5 and said layer of semiconductor material comprises silicon.
Claim 5
Dependent Claim
32 words
The method of claim 1 wherein said graded layer of Ge x Si l-x has a final composition in the range (0.65≦x≦1.0) and said layer of semiconductor material comprises indium gallium phosphide.
Claim 6
Dependent Claim
34 words
The method of claim 1 wherein said graded layer of Ge x Si l-x has a final composition of pure germanium and said layer of semiconductor material comprises gallium arsenide or aluminum gallium arsenide.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein said epitaxial layers are grown by molecular beam epitaxy.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein said epitaxial layers are grown by chemical vapor deposition.
Claim 9
Dependent Claim
42 words
The method of claim 1 further comprising the step of providing said silicon substrate with a recessed to tub having a depth equal to the sum of the thickness of the graded layer of Ge x Si l-x and the cap layer.
Claim 10
Dependent Claim
34 words
The method of claim 1 wherein the temperature of growth of said graded layer of Ge x Si l-x is scaled in proportion to the melting temperature of the Ge x Si l-x .
Claim 11
Dependent Claim
20 words
The method of claim 1 wherein the area of said graded Ge x Si l-x layer exceeds 12,000 square microns.
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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) | 1996-06-21 | 1996-12-21 | 1997-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-21 | 2000-12-21 | 2001-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-21 | 2004-12-21 | 2005-06-22 | $7700.00 | Window Closed / Lapsed |