Patent US5532177A successfully refreshed from Google Patents.
US5532177A
Expired / Lapsed
US
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Method for forming electron emitters
Assignee: Micron Technology Inc
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Filing: 1993-07-07
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Granted: 1996-07-02
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Expires: 2013-07-07
Abstract
Abstract Electron emitters and a method of fabricating emitters which have a concentration gradient of impurities, such that the highest concentration of impurities is at the apex of the emitters, and decreases toward the base of the emitters. The method comprises the steps of doping, patterning, etching, and oxidizing the substrate, thereby forming the emitters having impurity gradients.
Inventors
- 👤 David A. Cathey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:50
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/30; H01J1/304; H01J1/3042; H01J1/3044; H01J9/00; H01J9/02; H01J9/022; H01J9/025; H01J2201/00; H01J2201/30; H01J2201/304; H01J2201/30403; Y; Y10; Y10S; Y10S148/00; Y10S148/116; Y10S148/172; Y10S438/00; Y10S438/978
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
72 words
A process for fabricating emitters, said process comprising the following steps of: forming a dopant concentration gradient of a dopant in a substrate, wherein said substrate has a surface and said dopant substantially covers said surface; patterning said substrate; selectively removing portions of said substrate, thereby defining emitters; and sharpening said emitters, wherein said sharpening comprises oxidation, said emitters oxidize at a rate which is a function of said dopant concentration gradient.
Claim 2
Dependent Claim
72 words
A process for fabricating emitters, said process comprising the following steps of: forming a dopant concentration gradient of a dopant in a substrate, wherein said substrate has a surface and said dopant substantially covers said surface; patterning said substrate; selectively removing portions of said substrate, thereby defining emitters; and sharpening said emitters, wherein said sharpening comprises oxidation, said emitters oxidize at a rate which is a function of said dopant concentration gradient.
Claim 3
Dependent Claim
15 words
The process according to claim 1, wherein said patterning employs a photoresist/silicon nitride/silicon oxide sandwich.
Claim 4
Dependent Claim
17 words
The process according to claim 2, wherein said dopant concentration gradient decreases with depth into said substrate.
Claim 5
Dependent Claim
17 words
The process according to claim 2, wherein said dopant concentration gradient increases with depth into said substrate.
Claim 6
Independent Claim
103 words
A method for manufacturing emitters, said method comprising the following steps of: selectively removing portions of a substrate, thereby forming emitters, said substrate comprising a surface and a dopant comprising at least one of arsenic, phosphorous, and boron, said dopant substantially covers said surface and forms a concentration gradient in said substrate, said selective removal comprising etching, wherein said gradient decreases with depth into said substrate, said etching having a rate which decreases as the gradient decreases; patterning said substrate, said pattern being formed with a mask, said mask comprising a photoresist/silicon nitride/silicon oxide sandwich; and oxidizing said substrate, said substrate comprising silicon.
Claim 7
Independent Claim
103 words
A method for manufacturing emitters, said method comprising the following steps of: selectively removing portions of a substrate, thereby forming emitters, said substrate comprising a surface and a dopant comprising at least one of arsenic, phosphorous, and boron, said dopant substantially covers said surface and forms a concentration gradient in said substrate, said selective removal comprising etching, wherein said gradient decreases with depth into said substrate, said etching having a rate which decreases as the gradient decreases; patterning said substrate, said pattern being formed with a mask, said mask comprising a photoresist/silicon nitride/silicon oxide sandwich; and oxidizing said substrate, said substrate comprising silicon.
Claim 8
Dependent Claim
16 words
The method according to claim 5, wherein said emitters are incorporated in an electron emission device.
Claim 9
Dependent Claim
163 words
A process for fabricating an emitter, said process comprising the following steps of: providing a substrate having a substantially continuous face and a depth extending away from said face; applying a dopant substantially continuously across said face to form a dopant concentration gradient within said substrate progressively extending away from said face along said depth; patterning said substrate by positioning a mask over said face, thereby partitioning said face into an unmasked portion and a masked portion; selectively removing said substrate underlying said unmasked portion of said face, thereby retaining a substrate protuberance underlying said masked portion of said face, wherein said substrate protuberance has a base and an apex of substantially the same width, said width corresponding to the width of said mask; and sharpening said apex of said protuberance into a point or an edge by removing a portion of said apex, thereby defining an emitter, wherein said sharpening comprises oxidizing a portion of said protuberance and removing said oxidized portion.
Claim 10
Dependent Claim
163 words
A process for fabricating an emitter, said process comprising the following steps of: providing a substrate having a substantially continuous face and a depth extending away from said face; applying a dopant substantially continuously across said face to form a dopant concentration gradient within said substrate progressively extending away from said face along said depth; patterning said substrate by positioning a mask over said face, thereby partitioning said face into an unmasked portion and a masked portion; selectively removing said substrate underlying said unmasked portion of said face, thereby retaining a substrate protuberance underlying said masked portion of said face, wherein said substrate protuberance has a base and an apex of substantially the same width, said width corresponding to the width of said mask; and sharpening said apex of said protuberance into a point or an edge by removing a portion of said apex, thereby defining an emitter, wherein said sharpening comprises oxidizing a portion of said protuberance and removing said oxidized portion.
Claim 11
Dependent Claim
15 words
The process according to claim 7, wherein said masks comprises a photoresist/silicon nitride/silicon oxide sandwich.
References Cited (Backward Citations)
US3755704A
Cited
US3665241A
Cited
US3812559A
Cited
US3894332A
Cited
US3875442A
Cited
US3970887A
Cited
US5090932A
Cited
US4874981A
Cited
US4968382A
Cited
US4964946A
Cited
US5201992A
Cited
US5378658A
Cited
US5358908A
Cited
US5372973A
Cited
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