US4973378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making electronic devices
Assignee: The General Electric Company PLC
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Filing: 1990-02-27
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Granted: 1990-11-27
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Expires: 2010-02-27
Abstract
Abstract A field emission device which may be used, for example, as a surge arrester, comprises two electrode structures each comprising a substrate from which project tapered electrically-conductive emitter bodies. The structures are bonded together, face-to-face, so that the emitters all project into a sealed space formed between the substrates. The space may be evacuated or gas-filled. The emitters are formed by depositing a conductive layer on each substrate, forming masking pads on the layer at the required emitter positions, and etching the conductive layer to leave a tapered body beneath each pad. The dimensions of the emitter bodies and the spacing between the substrates are preferably of the order of a few microns.
Inventors
- 👤 Rosemary A. Lee
- 👤 William M. Lovell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:53
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J9/025; H01T; H01T4/00; H01T4/10; H01T4/12
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
86 words
A method of forming an electron emission device, the method comprising providing a first electrode structure comprising a first substrate with at least one tapered electrically-conductive body projecting therefrom; providing a second electrode structure comprising a second substrate with at least one tapered electrically-conductive body projecting therefrom; inverting said second electrode structure relative to said first electrode structure; and bonding the two electrode structures together with a space defined between the substrates and with the or each tapered body of each structure projecting into the space.
Claim 2
Independent Claim
86 words
A method of forming an electron emission device, the method comprising providing a first electrode structure comprising a first substrate with at least one tapered electrically-conductive body projecting therefrom; providing a second electrode structure comprising a second substrate with at least one tapered electrically-conductive body projecting therefrom; inverting said second electrode structure relative to said first electrode structure; and bonding the two electrode structures together with a space defined between the substrates and with the or each tapered body of each structure projecting into the space.
Claim 3
Dependent Claim
25 words
A method as claimed in claim 1, wherein each said electrically-conductive body is formed from a layer of electrically-conductive material provided on the respective substrate.
Claim 4
Dependent Claim
50 words
A method as claimed in claim 2, wherein each said electrically-conductive body is formed from said layer of electrically-conductive material by depositing a masking pad on said layer in the required position for the or each electrically-conductive body; and etching the layer to form said tapered body beneath the pad.
Claim 5
Dependent Claim
27 words
A method as claimed in claim 3, wherein the etching of the layer to form the or each electrically-conductive body is effected by a wet etching process.
Claim 6
Dependent Claim
27 words
A method as claimed in claim 3, wherein the etching of the layer to form the or each electrically-conductive body is effected by a dry etching process.
Claim 7
Dependent Claim
33 words
A method as claimed in claim 3, wherein the etching of the layer to form the or each electrically-conductive body is effected by a wet etching process followed by a dry etching process.
Claim 8
Dependent Claim
27 words
A method as claimed in claim 5, wherein the dry etching is effected by plasma etching, reactive ion etching, ion beam milling, or reactive ion beam milling.
Claim 9
Dependent Claim
28 words
A method as claimed in claim 7, wherein the dry etching is effected by a plasma etching process carried out in SF 6 /Cl 2 /O 2 .
Claim 10
Dependent Claim
27 words
A method as claimed in claim 7, wherein the dry etching is effected by a reactive ion etching process carried out in SF 6 /N 2 .
Claim 11
Dependent Claim
21 words
A method as claimed in claim 2, wherein the layer is formed of a semiconductor, a metal or a metal compound.
Claim 12
Dependent Claim
21 words
A method as claimed in claim 10, wherein the layer is formed of niobium, silicon, rhodium, molybdenum, gold, nickel or tungsten.
Claim 13
Dependent Claim
19 words
A method as claimed in claim 11, wherein the layer is formed of single crystal nickel, tungsten or rhodium.
Claim 14
Dependent Claim
38 words
A method as claimed in claim 1, further comprising the step of forming a frame of dielectric material round the periphery of at least one of the electrode structures to act as a spacer between the electrode structures.
Claim 15
Dependent Claim
26 words
A method as claimed in claim 13, wherein the or each frame of dielectric material has a metal layer thereon for use in the bonding step.
Claim 16
Dependent Claim
20 words
A method as claimed in claim 14, wherein the metal layer of the or each frame is formed of aluminium.
Claim 17
Dependent Claim
32 words
A method as claimed in claim 1, wherein the or each tapered body of the first electrode structure is substantially axially aligned with a respective tapered body of the second electrode structure.
Claim 18
Dependent Claim
28 words
A method as claimed in claim 1, wherein the or each tapered body of each electrode structure points towards a substantially planar region of the other electrode structure.
Claim 19
Dependent Claim
16 words
A method as claimed in claim 1, wherein said space defined between the substrates is evacuated.
Claim 20
Dependent Claim
16 words
A method as claimed in claim 1, wherein said space defined between the substrates is gas-filled.
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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) | 1993-11-26 | 1994-05-28 | 1994-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-26 | 1998-05-28 | 1998-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-26 | 2002-05-28 | 2002-11-27 | $7700.00 | Window Closed / Lapsed |