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US5075243A
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Fabrication of nanometer single crystal metallic CoSi2 structures on Si
Assignee: National Aeronautics and Space Administration
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Filing: 1991-03-27
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Granted: 1991-12-24
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Expires: 2011-03-27
Abstract
Abstract Amorphous Co:Si (1:2 ratio) films (12) are electron gun-evaporated on clean Si(111) substrates (10), such as in a molecular beam epitaxy system. These layers are then crystallized selectively with a focused electron beam (14) to form very small crystalline CoSi 2 regions (12') in an amorphous matrix. Finally, the amorphous regions are etched away selectively using plasma or chemical techniques.
Inventors
- 👤 Kai-Wei Nieh
- 👤 True-Lon Lin
- 👤 Robert W. Fathauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:16
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/0042; H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01318; H10D64/0132; H10P; H10P76/00; H10P76/40; H10P76/405; Y; Y10; Y10S; Y10S148/00; Y10S148/046; Y10S148/048; Y10S148/154
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
108 words
Method for forming features on a substrate, said features having sub-micrometer lateral dimensions comprising: (a) forming an amorphous coating on said substrate, said amorphous coating comprising a material capable of controlled crystallization; (b) exposing a portion of said material to a focussed electron beam for a period of time and with sufficient electron energy and dose to crystallize said portion, said electron energy ranging from about 20 to 300 keV, while maintaining said coating at a temperature ranging from room temperature to 150° C., the lower temperatures being associated with the higher electron energies; and (c) removing all amorphous coating remaining, leaving said crystallized portion on said substrate.
Claim 2
Dependent Claim
108 words
Method for forming features on a substrate, said features having sub-micrometer lateral dimensions comprising: (a) forming an amorphous coating on said substrate, said amorphous coating comprising a material capable of controlled crystallization; (b) exposing a portion of said material to a focussed electron beam for a period of time and with sufficient electron energy and dose to crystallize said portion, said electron energy ranging from about 20 to 300 keV, while maintaining said coating at a temperature ranging from room temperature to 150° C., the lower temperatures being associated with the higher electron energies; and (c) removing all amorphous coating remaining, leaving said crystallized portion on said substrate.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein said substrate comprises a material selected from the group consisting of silicon, silicon dioxide, and CaF 2 .
Claim 4
Dependent Claim
21 words
The method of claim 2 wherein said amorphous coating comprises a material selected from the group consisting of cobalt:silicon and iridium:silicon.
Claim 5
Dependent Claim
21 words
The method of claim 3 wherein said amorphous coating consists essentially of cobalt:silicon in an atomic ratio of Co:Si of 1:2.
Claim 6
Dependent Claim
13 words
The method of claim 4 wherein said crystallized portion comprises CoSi 2 .
Claim 7
Dependent Claim
24 words
The method of claim 1 said electron energy ranges from about 200 to 300 keV and said coating is maintained at about room temperature.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein said electron energy ranges from about 20 to 50 keV and wherein said elevated temperature is about 150° C.
Claim 9
Dependent Claim
19 words
The method of claim 1 wherein said dose is at least about 10 21 cm -1 min -1 .
Claim 10
Dependent Claim
30 words
The method of claim 1 wherein said substrate comprises silicon, said amorphous coating comprises Co:Si, deposited in a stoichiometric ratio of 1:2, and said crystallized portion comprises CoSi 2 .
Claim 11
Independent Claim
114 words
A method for fabricating field effect transistors having submicrometer gate lengths comprising: (a) forming a polycrystalline coating on a layer of silicon dioxide, said polycrystalline coating comprising a material capable of controlled crystallization; (b) exposing a portion of said material to a focussed electron beam for a period of time and with sufficient electron energy and dose to convert said portion to a single crystal portion, said electron energy ranging from about 20 to 300 keV, while maintaining said coating at a temperature ranging from room temperature to 150° C., the lower temperatures being associated with the higher electron energies; and (c) removing all polycrystalline coating remaining, leaving said single-crystal portion on said substrate.
Claim 12
Independent Claim
114 words
A method for fabricating field effect transistors having submicrometer gate lengths comprising: (a) forming a polycrystalline coating on a layer of silicon dioxide, said polycrystalline coating comprising a material capable of controlled crystallization; (b) exposing a portion of said material to a focussed electron beam for a period of time and with sufficient electron energy and dose to convert said portion to a single crystal portion, said electron energy ranging from about 20 to 300 keV, while maintaining said coating at a temperature ranging from room temperature to 150° C., the lower temperatures being associated with the higher electron energies; and (c) removing all polycrystalline coating remaining, leaving said single-crystal portion on said substrate.
Claim 13
Dependent Claim
11 words
The method of claim 10 wherein said polycrystalline coating comprises cobalt:silicon.
Claim 14
Dependent Claim
21 words
The method of claim 11 wherein said polycrystalline coating consists essentially of cobalt:silicon in an atomic ratio of Co:Si of 1:2.
Claim 15
Dependent Claim
13 words
The method of claim 12 wherein said single-crystal portion comprises CoSi 2 .
Claim 16
Dependent Claim
27 words
The method of claim 10 said electron energy ranges from about 200 to 300 keV and said coating is maintained at a temperature of about 150° C.
Claim 17
Dependent Claim
25 words
The method of claim 10 wherein said electron energy ranges from about 20 to 50 keV and wherein said elevated temperature is about 150° C.
Claim 18
Dependent Claim
19 words
The method of claim 10 wherein said dose is at least about 10 21 cm -1 min -1 .
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