US4547230A
Expired / Lapsed
US
⏱️ 0.0 years remaining
LPE Semiconductor material transfer method
Assignee: United States Department of the Air Force
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Filing: 1984-07-30
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Granted: 1985-10-15
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Expires: 2004-07-30
Abstract
Abstract A method for liquid phase epitaxy maskless deposition of a III-V compound on a substrate in a pre-determined pattern includes the steps of contacting a growth wafer having a patterned mask thereon to a growth solution in equilibrium and then increasing the temperature of the growth solution and wafer thereby locally melting the exposed portions of the wafer surface and locally changing the equilibrium properties of the growth solution. The substrate upon which the material is to be deposited is then contacted with the growth solution and the temperature lowered. Because of the locally varying equilibrium conditions the constituents of the growth solution will be preferentially deposited on those portions of the substrate corresponding to the unmasked portions of the growth wafer.
Inventors
- 👤 Frank Z. Hawrylo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:55
CPC Classifications
C; C30; C30B; C30B19/00; C30B19/12; Y; Y10; Y10S; Y10S438/00; Y10S438/955
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
212 words
A method of transferring semiconductor material to form predetermined patterns by liquid phase epitaxy, said method comprising the steps of: (1) preparing a top surface of a growth wafer for photolithography; (2) placing a mask on said wafer, said mask having areas removed whereby said top surface of said growth wafer has selected exposed areas; (3) preparing a liquid growth solution in a well of furnace boat, said growth solution having elemental constituents the same as said growth wafer; (4) heating said growth solution for a period of time so that an equilibrium is established in said growth solution; (5) placing said growth wafer in contact with said growth solution; (6) raising the temperature of said growth solution a predetermined amount based upon the amount of semiconductor material to be transferred and the length of time exposed to said growth wafer at an elevated temperature; (7) removing said growth wafer from said growth solution; (8) lowering the temperature of said growth solution in a controlled manner; (9) selectively placing a seed wafer under said growth solution at about equilibrium; (10) lowering the temperature a predetermined amount so that non-equilibrium conditions cause epitaxial deposition of said material; and (11) removing said seed wafer from said growth solution after epitaxial deposition of said patterns.
Claim 2
Independent Claim
212 words
A method of transferring semiconductor material to form predetermined patterns by liquid phase epitaxy, said method comprising the steps of: (1) preparing a top surface of a growth wafer for photolithography; (2) placing a mask on said wafer, said mask having areas removed whereby said top surface of said growth wafer has selected exposed areas; (3) preparing a liquid growth solution in a well of furnace boat, said growth solution having elemental constituents the same as said growth wafer; (4) heating said growth solution for a period of time so that an equilibrium is established in said growth solution; (5) placing said growth wafer in contact with said growth solution; (6) raising the temperature of said growth solution a predetermined amount based upon the amount of semiconductor material to be transferred and the length of time exposed to said growth wafer at an elevated temperature; (7) removing said growth wafer from said growth solution; (8) lowering the temperature of said growth solution in a controlled manner; (9) selectively placing a seed wafer under said growth solution at about equilibrium; (10) lowering the temperature a predetermined amount so that non-equilibrium conditions cause epitaxial deposition of said material; and (11) removing said seed wafer from said growth solution after epitaxial deposition of said patterns.
Claim 3
Dependent Claim
16 words
A method as defined in claim 1 wherein said growth wafer is composed of III-V elements.
Claim 4
Dependent Claim
23 words
A method as defined in claim 2 wherein said III-V elements are selected from the group consisting of InP, GaAs, InGaAsP and AlGaAs.
Claim 5
Dependent Claim
31 words
A method as defined in claim 1 wherein steps 5 and 6 are reversed whereby the temperature is raised after said growth wafer is placed in contact with said growth solution.
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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) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |