US5091333A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reducing dislocations in semiconductors utilizing repeated thermal cycling during multistage epitaxial growth
Assignee: Massachusetts Institute of Technology
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Filing: 1988-09-07
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Granted: 1992-02-25
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Expires: 2008-09-07
Abstract
Abstract Dislocation densities are reduced in growing semiconductors from the vapor phase by employing a technique of interrupting growth, cooling the layer so far deposited, and then repeating the process until a high quality active top layer is achieved. The method of interrupted growth, coupled with thermal cycling, permits dislocations to be trapped in the initial stages of epitaxial growth.
Inventors
- 👤 John C. C. Fan
- 👤 Bor-Yeu Tsaur
- 👤 Ronald P. Gale
- 👤 Frances M. Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:02
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/34; H10P14/3402; H10P14/3414; H10P14/3421; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/32; H10P14/3202; H10P14/3204; H10P14/3211; H10P14/3214; H10P14/3221; H10P14/3242; H10P14/3244; H10P14/3248; Y; Y10; Y10S; Y10S148/00; Y10S148/003; Y10S148/025; Y10S148/097; Y10S438/00; Y10S438/938
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
132 words
A method of forming layers of material upon a substrate having a thermal coefficient of expansion different than that of the layers, the method comprising: (a) depositing at least a portion of a layer of the material upon the substrate by deposition at a growth temperature substantially above ambient but below the melting point of the material; (b) reducing the growth temperature to an intermediate temperature to induce a thermal stress therein and thereby trap dislocations in the layer portion formed by lattice mismatch between the layer portion and the substrate; (c) depositing additional layer material on the deposited layer portion at a growth temperature above said intermediate temperature; and (d) repeating the steps of reducing the growth temperature and depositing additional layer material to further trap dislocations in the layer material.
Claim 2
Independent Claim
132 words
A method of forming layers of material upon a substrate having a thermal coefficient of expansion different than that of the layers, the method comprising: (a) depositing at least a portion of a layer of the material upon the substrate by deposition at a growth temperature substantially above ambient but below the melting point of the material; (b) reducing the growth temperature to an intermediate temperature to induce a thermal stress therein and thereby trap dislocations in the layer portion formed by lattice mismatch between the layer portion and the substrate; (c) depositing additional layer material on the deposited layer portion at a growth temperature above said intermediate temperature; and (d) repeating the steps of reducing the growth temperature and depositing additional layer material to further trap dislocations in the layer material.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein the method further comprises first coating the substrate with a coating to insulate the material from the effects of substrate-to-layer lattice mismatch.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein the substrate is silicon and the layer material is comprised of a III-V compound.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein the layer material is comprised of GaAs.
Claim 6
Dependent Claim
22 words
The method of claim 1 wherein the layer material is comprised of a II-VI compound and the substrate is comprised of InP.
Claim 7
Dependent Claim
26 words
The method of claim 1 wherein the layer material is comprised of a semiconductor material taken from the class comprising GaAs, Ge, Si, InP, or GaP.
Claim 8
Independent Claim
127 words
A method of forming layers of material upon a substrate having a thermal coefficient of expansion different than that of the layers, the method comprising: (a) depositing at least a portion of a layer material upon the substrate by deposition at a growth temperature substantially above ambient; (b) increasing the growth temperature to an elevated temperature without melting of the layer to induce a thermal stress therein and thereby trap dislocations in the layer portion formed by lattice mismatch between the layer portion and the substrate; (c) depositing additional layer material on the deposited layer portion at a growth temperature below said elevated temperature; and (d) repeating the steps of increasing the growth temperature and depositing additional layer material to further trap dislocations in the layer material.
Claim 9
Independent Claim
127 words
A method of forming layers of material upon a substrate having a thermal coefficient of expansion different than that of the layers, the method comprising: (a) depositing at least a portion of a layer material upon the substrate by deposition at a growth temperature substantially above ambient; (b) increasing the growth temperature to an elevated temperature without melting of the layer to induce a thermal stress therein and thereby trap dislocations in the layer portion formed by lattice mismatch between the layer portion and the substrate; (c) depositing additional layer material on the deposited layer portion at a growth temperature below said elevated temperature; and (d) repeating the steps of increasing the growth temperature and depositing additional layer material to further trap dislocations in the layer material.
Claim 10
Dependent Claim
28 words
The method of claim 7 wherein the method further comprises first coating the substrate with a coating to insulate the material from the effects of substrate-to-layer lattice mismatch.
Claim 11
Dependent Claim
20 words
The method of claim 7 wherein the substrate is silicon and the layer material is comprised of a III-V compound.
Claim 12
Dependent Claim
13 words
The method of claim 7 wherein the layer material is comprised of GaAs.
Claim 13
Dependent Claim
22 words
The method of claim 7 wherein the layer material is comprised of a II-VI compound and the substrate is comprised of InP.
Claim 14
Dependent Claim
26 words
The method of claim 7 wherein the layer material is comprised of a semiconductor material taken from the class comprising GaAs, Ge, Si, InP, or GaP.
Claim 15
Independent Claim
125 words
A method of forming layer materials upon a substrate wherein the substrate has a thermal coefficient of expansion different than that of the materials, the method comprising: (a) depositing at least a portion of a layer of material upon the substrate by deposition at a growth temperature substantially above ambient; (b) changing the temperature of the deposited material to an intermediate temperature below the melting temperature of the deposited material to induce a thermal stress therein and thereby trap dislocations in the layer portion; (c) depositing additional layer material on the layer portion at a growth temperature different than the intermediate temperature; and (d) repeating the steps of changing the growth temperature and depositing additional layer material to further trap dislocations in the layer materials.
Claim 16
Independent Claim
125 words
A method of forming layer materials upon a substrate wherein the substrate has a thermal coefficient of expansion different than that of the materials, the method comprising: (a) depositing at least a portion of a layer of material upon the substrate by deposition at a growth temperature substantially above ambient; (b) changing the temperature of the deposited material to an intermediate temperature below the melting temperature of the deposited material to induce a thermal stress therein and thereby trap dislocations in the layer portion; (c) depositing additional layer material on the layer portion at a growth temperature different than the intermediate temperature; and (d) repeating the steps of changing the growth temperature and depositing additional layer material to further trap dislocations in the layer materials.
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) | 1995-02-24 | 1995-08-26 | 1996-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-24 | 1999-08-26 | 2000-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-24 | 2003-08-26 | 2004-02-25 | $7700.00 | Window Closed / Lapsed |