EP0508737A1
Expired / Lapsed
EP
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Method of producing metallic microscale cold cathodes
Assignee: Fujitsu Ltd
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Filing: 1992-04-08
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Granted: —
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Expires: 2012-04-08
Abstract
Abstract Microscale cold cathodes comprising a metallic emitter tip (21) with a very sharp end are manufactured by a method comprising forming a cone (20) of metal on a substrate (1) [Fig. 1C], oxidizing the surface of the cone [Fig. 1D], and removing the oxidized film (3) from the cone surface to produce an emitter tip [Fig. 1F].
Inventors
- 👤 Shinya Fukuta
- 👤 Keiichi Betsui
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 07:26
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J9/025; H01J2209/00; H01J2209/02; H01J2209/022; H01J2209/0223; H01J2209/0226
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
129 words
A method of producing a metallic microscale cold cathode comprising a metallic emitter tip (21) formed on a substrate (1), the emitter tip (21) being located inside an aperture formed in a gate electrode (80) of a metallic film provided on an insulating film (7) surrounding the emitter tip (21), characterized in that the method comprises forming a metallic emitter tip by a process comprising steps of: (i) forming a cone (20) consisting of a metallic material (2) for the emitter tip on a substrate (1), (ii) oxidizing the surface of the cone of metal to thereby form an oxidized film (3), and (iii) forming an emitter tip (21) having a reduced radius of curvature by removing the oxidized film (3) from the surface of the metal cone (20).
Claim 2
Dependent Claim
21 words
The method of claim 1, characterized in that the oxidization of the surface of the cone (20) is effected by anodizing.
Claim 3
Dependent Claim
33 words
The method of claim 1 or 2, characterized in that the oxidized film (3) is removed by an electrically protecting treatment using the unoxidized metal material for the emitter tip as a cathode.
Claim 4
Independent Claim
42 words
The method of any of claims 1 to 3, characterized in that the cone (20) is formed from a film of a metallic material formed on another material as the substrate (1), or the cone (20) is formed from a metallic substrate.
Claim 5
Independent Claim
23 words
The method of any of claims 1 to 4, characterized in that the cone (20) is made of tantalum, molybdenum, titanium or niobium.
Claim 6
Independent Claim
251 words
A method of producing a metallic microscale cold cathode comprising a metallic emitter tip (21) formed on a substrate (1), the emitter tip (21) being located inside an aperture formed in a gate electrode (80) of metallic film provided on an insulating film (7) surrounding the emitter tip (21), characterized in that the method comprises steps of: (a) forming an insulation film (3) on a metallic material (2) to be formed into an emitter tip, (b) patterning the insulation film (3) to form a mask (5′) of the insulation film, (c) etching the metallic material (2) using the mask (5′) to thereby form a cone (20) of the metal beneath the mask (5′), (d) oxidizing the surface of the remaining metallic material (2) to form an oxidized metal film (3), thereby forming an emitter tip (21) of the unoxidized metal material inside the oxidized film (3), (e) successively forming over the substrate (1) an insulating film (7) and a metallic film (8) to make a gate electrode, (f) removing the oxidized film (3) under the mask (5′), which has been uncovered by the insulating film (7) and metallic film (8) in the step (e), to thus lift off the mask (5′) and expose the emitter tip (21) while forming an aperture, by which the emitter tip (21) and the gate electrode (80) are separated from each other, and (g) patterning the metallic film (8) on the insulating film (7) formed in the step (e) to thereby form a gate electrode (80).
Claim 7
Dependent Claim
21 words
The method of claim 6, characterized in that the oxidization of the surface of the cone (20) is effected by anodizing.
Claim 8
Dependent Claim
33 words
The method of claim 6 or 7, characterized in that the oxidized film (3) is removed by an electrically protecting treatment using the unoxidized metal material for the emitter tip as a cathode.
Claim 9
Independent Claim
41 words
The method of any of claims 6 to 8, characterized in that the cone (20) is formed from a film of a metallic material formed on another material as the substrate, or the cone (20) is formed from a metallic substrate.
Claim 10
Independent Claim
23 words
The method of any of claims 6 to 9, characterized in that the cone (20) is made of tantalum, molybdenum, titanium or niobium.
References Cited (Backward Citations)
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