US5455196A
Expired / Lapsed
US
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Method of forming an array of electron emitters
Assignee: Texas Instruments Inc
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Filing: 1994-03-17
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Granted: 1995-10-03
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Expires: 2014-03-17
Abstract
Abstract A method of forming an array of electron field emitters at a face of a semiconductor layer is disclosed. The method includes the steps of: providing a semiconductor workpiece having a plurality of field emitter sites on a face thereof; for each site, forming a conductive column having a base coupled to the site and an upstanding end opposed to the base; for each conductive column, forming a metallic column on the upstanding end of the conductive column; depositing an electrically conductive polymer layer over the workpiece; etching the electrically conductive polymer layer to selectively expose the metallic columns; placing the workpiece in an electrolytic etchant solution capable of etching the metallic columns; applying an electric potential between the conductive polymer layer and an anode electrode in the etchant to etch the metallic columns into a respective plurality of sharp emitter tips; and removing the conductive polymer layer. Where the metallic column is tungsten, an aqueous solution of potassium hydroxide is disclosed as an etchant. Where the metallic column is a platinum-iridium alloy, an aqueous solution of calcium chloride and hydrochloric acid is disclosed as an etchant.
Inventors
- 👤 Gary A. Frazier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:12
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/04; H01J1/00; H01J1/02; H01J1/30; H01J1/304; H01J1/3042; H01J31/00; H01J31/08; H01J31/10; H01J31/20; H01J31/201; H01J31/203; H01J9/00; H01J9/02; H01J9/022; H01J9/025; H01J2201/00; H01J2201/30; H01J2201/319; Y; Y10; Y10S; Y10S148/00; Y10S148/172
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
148 words
A method of forming an array of electron field emitters at a face of a semiconductor layer, comprising the steps of: providing a semiconductor workpiece having a face and including a plurality of field emitter sites on the face; for each site, forming a conductive column having a base coupled to the site and an upstanding end opposed to the base; for each conductive column, forming a metallic column on the upstanding end of the conductive column; depositing an electrically conductive polymer layer over the workpiece; etching the electrically conductive polymer layer to selectively expose the metallic columns; placing the workpiece in an electrolytic etchant solution capable of etching the metallic columns; applying an electric potential between the conductive polymer layer and a counterelectrode in said electrolytic etchant solution to etch the metallic columns into a respective plurality of sharp emitter tips; and removing the conductive polymer layer.
Claim 2
Independent Claim
148 words
A method of forming an array of electron field emitters at a face of a semiconductor layer, comprising the steps of: providing a semiconductor workpiece having a face and including a plurality of field emitter sites on the face; for each site, forming a conductive column having a base coupled to the site and an upstanding end opposed to the base; for each conductive column, forming a metallic column on the upstanding end of the conductive column; depositing an electrically conductive polymer layer over the workpiece; etching the electrically conductive polymer layer to selectively expose the metallic columns; placing the workpiece in an electrolytic etchant solution capable of etching the metallic columns; applying an electric potential between the conductive polymer layer and a counterelectrode in said electrolytic etchant solution to etch the metallic columns into a respective plurality of sharp emitter tips; and removing the conductive polymer layer.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein said metallic columns are formed of tungsten, said electrolytic etchant solution comprising an aqueous solution of potassium hydroxide.
Claim 4
Dependent Claim
17 words
The method of claim 2, wherein said aqueous solution comprises about 5 percent by weight potassium hydroxide.
Claim 5
Dependent Claim
24 words
The method of claim 3, wherein said aqueous solution comprises about 60 percent by weight calcium chloride and 4 percent by weight hydrochloric acid.
Claim 6
Dependent Claim
29 words
The method of claim 1, wherein said metallic columns are formed of a platinum-iridium alloy, said electrolytic etchant solution comprising an aqueous solution of calcium chloride and hydrochloric acid.
Claim 7
Dependent Claim
14 words
The method of claim 1, wherein said conductive polymer layer comprises a doped polyamide.
Claim 8
Dependent Claim
28 words
The method of claim 1, wherein the potential applied between the conductive polymer layer and the counterelectrode is in the range of 5 to 15 volts AC, inclusive.
Claim 9
Independent Claim
103 words
A method of forming an electron field emitter at a face of a semiconductor layer, comprising the steps of: forming a conductive body having a base coupled to said face and having a metallic portion on the end of said conductive body opposite said face; forming an electrically conductive polymer layer over said face so as to expose said metallic portion; immersing said metallic portion and said conductive polymer layer in an electrolytic etchant solution; applying an electric potential between said conductive polymer layer and a counterelectrode in said electrolytic etchant solution to thereby etch said metallic portion into a sharp emitter tip.
Claim 10
Independent Claim
103 words
A method of forming an electron field emitter at a face of a semiconductor layer, comprising the steps of: forming a conductive body having a base coupled to said face and having a metallic portion on the end of said conductive body opposite said face; forming an electrically conductive polymer layer over said face so as to expose said metallic portion; immersing said metallic portion and said conductive polymer layer in an electrolytic etchant solution; applying an electric potential between said conductive polymer layer and a counterelectrode in said electrolytic etchant solution to thereby etch said metallic portion into a sharp emitter tip.
Claim 11
Dependent Claim
26 words
The method in accordance with claim 8, wherein said metallic portion is formed of tungsten, said electrolytic etchant solution comprising an aqueous solution of potassium hydroxide.
Claim 12
Dependent Claim
19 words
The method in accordance with claim 9, wherein said aqueous solution comprises about 5 percent by weight potassium hydroxide.
Claim 13
Dependent Claim
31 words
The method in accordance with claim 8, wherein said metallic portion is formed of a platinum-iridium alloy, said electrolytic etchant solution comprising an aqueous solution of calcium chloride and hydrochloric acid.
Claim 14
Dependent Claim
26 words
The method in accordance with claim 11, wherein said aqueous solution comprises about 60 percent by weight calcium chloride and 4 percent by weight hydrochloric acid.
Claim 15
Dependent Claim
16 words
The method in accordance with claim 8, wherein said conductive polymer layer comprises a doped polyamide.
Claim 16
Dependent Claim
29 words
The method in accordance with claim 8, wherein the potential applied between said conductive polymer layer and said counterelectrode is in the range of 5 to 15 volts AC.
Claim 17
Dependent Claim
40 words
The method in accordance with claim 8, wherein said step of forming an electrically conductive polymer layer comprises: depositing an electrically conductive polymer layer over said face; and etching said electrically conductive polymer layer to selectively expose said metallic portion.
Claim 18
Dependent Claim
21 words
The method in accordance with claim 8, further including a final step of removing said conductive polymer layer from said face.
Claim 19
Independent Claim
112 words
A method of forming an array of electron field emitters at a face of a semiconductor layer, comprising the steps of: providing a semiconductor workpiece having face; forming a plurality of conductive columns on said face, said columns having their respective bases coupled to said face, each column having a metallic portion on the end thereof opposite said base; forming an electrically conductive polymer layer over said face so as to expose said metallic portions; immersing said semiconductor workpiece in an electrolytic etchant solution; and applying an electric potential between said conductive polymer layer and a counterelectrode in said electrolytic etchant solution to thereby etch said metallic portions into sharp emitter tips.
Claim 20
Independent Claim
112 words
A method of forming an array of electron field emitters at a face of a semiconductor layer, comprising the steps of: providing a semiconductor workpiece having face; forming a plurality of conductive columns on said face, said columns having their respective bases coupled to said face, each column having a metallic portion on the end thereof opposite said base; forming an electrically conductive polymer layer over said face so as to expose said metallic portions; immersing said semiconductor workpiece in an electrolytic etchant solution; and applying an electric potential between said conductive polymer layer and a counterelectrode in said electrolytic etchant solution to thereby etch said metallic portions into sharp emitter tips.
Claim 21
Dependent Claim
40 words
The method in accordance with claim 17, wherein said step of forming an electrically conductive polymer layer comprises: depositing an electrically conductive polymer layer over said face; and etching said electrically conductive polymer layer to selectively expose said metallic portions.
Claim 22
Dependent Claim
21 words
The method in accordance with claim 17, further including a final step of removing said conductive polymer layer from said face.
Claim 23
Dependent Claim
29 words
The method in accordance with claim 17, wherein the potential applied between said conductive polymer layer and said counterelectrode is in the range of 5 to 15 volts AC.
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