Patent EP0260075A2 successfully refreshed from Google Patents.
EP0260075A2
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EP
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Vacuum devices
Assignee: The General Electric Company PLC
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Filing: 1987-09-04
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Granted: —
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Expires: 2007-09-04
Abstract
Abstract A vacuum valve device comprises a substrate (1) on which is formed an undoped silicon layer (3) from which a silicon dioxide layer (5) is grown. First, second and third electrode structures (7, 9, 11) are formed on the silicon dioxide layer by depositing a metallic layer and etching away unwanted portions of the layer. The first electrode structure (7) has a pointed end (8) and/or a sharp edge and/or is formed of low work function material so that, when a suitable voltage is applied between the first and third electrode structures, electrons are emitted from the first electrode structure due to a field emission process. Electrons therefore flow from the first to the third electrode structure substantially parallel to the substrate. The third electrode structure acts as a control electrode.
Inventors
- 👤 Rosemary Ann Lee
- 👤 Neil Alexander Cade
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 09:16
CPC Classifications
H; H01; H01J; H01J21/00; H01J21/02; H01J21/06; H01J21/10; H01J21/105
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
43 words
A vacuum device, characterised by a substrate (1); and at least first and second electrode structures (7,9,11) of substantially co-planar construction formed on the substrate for electron flow from the first electrode structure to the second electrode structure substantially parallel to the substrate.
Claim 2
Dependent Claim
43 words
A vacuum device, characterised by a substrate (1); and at least first and second electrode structures (7,9,11) of substantially co-planar construction formed on the substrate for electron flow from the first electrode structure to the second electrode structure substantially parallel to the substrate.
Claim 3
Dependent Claim
30 words
A device as claimed in Claim 1, characterised in that, in use of the device, electrons are emitted from the first electrode structure (7) by an electric field induced process.
Claim 4
Dependent Claim
39 words
A device as claimed in Claim 1 or Claim 2, characterised in that the first electrode structure (7) has a lower work function than the second electrode structure (11), whereby electrons are preferentially emitted from the first electrode structure.
Claim 5
Dependent Claim
39 words
A device as claimed in Claim 1 or Claim 2, characterised in that the first electrode structure (7) has a thin edge (12) facing the second electrode structure (11) for enhancement of electron emission from the first electrode structure.
Claim 6
Independent Claim
36 words
A device as claimed in any preceding claim, characterised in that the first electrode structure (7) tapers in a direction towards the second electrode structure (11) for enhancement of electron emission from the first electrode structure.
Claim 7
Dependent Claim
32 words
A device as claimed in Claim 1 or Claim 2, characterised in that the first electrode structure (7) includes an implanted dopant for enhancement of electron emission from the first electrode structure.
Claim 8
Independent Claim
30 words
A device as claimed in any preceding claim, characterised in that the first electrode structure (7) has a surface coating for enhancement of electron emission from the first electrode structure.
Claim 9
Independent Claim
36 words
A device according to any preceding claim, characterised by a third electrode structure (9) which in use of the device regulates the electron flow from the first electrode structure (7) to the second electrode structure (11).
Claim 10
Dependent Claim
96 words
A device according to Claim 8, characterised by a channel (23) formed in the substrate (26); a first conductive layer (28) deposited over the channel and opposing areas of the substrate on the sides of the channel; and a second conductive layer (29) formed over the first conductive layer, the first layer being of a material of lower work function than that of the second layer, the first layer in said opposing areas constituting parts of the first and second electrode structures, and the second layer within the channel constituting part of the third electrode structure.
Claim 11
Dependent Claim
45 words
A process for forming a vacuum device, characterised by forming on a common substrate (1) at least first and second electrode structures (7,9,11) of substantially co-planar construction for electron flow from the first electrode structure to the second electrode structure substantially parallel to the substrate.
Claim 12
Dependent Claim
45 words
A process for forming a vacuum device, characterised by forming on a common substrate (1) at least first and second electrode structures (7,9,11) of substantially co-planar construction for electron flow from the first electrode structure to the second electrode structure substantially parallel to the substrate.
Claim 13
Dependent Claim
56 words
A process as claimed in Claim 10, characterised by forming an insulating layer (5) on the substrate (1); forming a conductive layer over the insulating layer; and etching away one or more portions of the conductive layer to leave areas of the conductive layer forming the first and second electrode structures (7,11) spaced from one another.
Claim 14
Dependent Claim
28 words
A process as claimed in Claim 11, characterised by forming a third electrode structure (9) from a further area of the conductive layer for controlling the electron flow.
Claim 15
Dependent Claim
36 words
A process as claimed in Claim 11, characterised in that an undoped silicon layer (3) is deposited on the substrate (1) and a silicon dioxide layer is thermally grown therefrom to form the insulating layer (5).
Claim 16
Dependent Claim
45 words
A process as claimed in any one of Claims 11 to 13, characterised in that the conductive layer is formed by vacuum evaporation or sputtering of refractory metal, such as tungsten, molybdenum, or a material or combination of materials giving a low work function surface.
Claim 17
Dependent Claim
25 words
A process as claimed in any one of Claims 11 to 13, characterised in that a dopant is implanted into the first electron structure (7).
Claim 18
Dependent Claim
36 words
A process as claimed in Claim 12, characterised in that portions of the insulating layer (5) between the first and third electrode structures (7,9) and between the third and second electrode structures (9,11) are etched away.
Claim 19
Dependent Claim
38 words
A process as claimed in Claim 16, characterised in that following the etching away of the portions of the insulating layer (5), the insulating layer beneath the facing edges of the electrode structures is undercut by isotropic etching.
Claim 20
Dependent Claim
120 words
A process as claimed in Claim 10, characterised by forming an insulating layer (26) on the substrate; etching a channel (23) into the insulating layer; depositing a first layer (28) of a low work function material over the insulating layer; and depositing a second layer (29) of a high work function material over the first layer; wherein the depth of the channel is sufficient such that the portion of the first and second layers within the channel is separated from the portions of either side of the channel, whereby said first and second electrode structures (30,31) are formed on either side of the channel, and a separate third electrode structure for controlling the electron flow is formed within the channel.
References Cited (Backward Citations)
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