Field emission device
AssigneeThomson-CSF
InventorsPierre Legagneux, Didier Pribat
Life of this patent
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Abstract
A field-emission device includes at least one plane cathode made of conductive material with a low electron affinity located on a face of a substrate carrying a layer of a dielectric material, which layer has at least one cavity in which the cathode is located. A gate made of conductive material is located on the dielectric layer and has an aperture centered with respect to the cavity. The conductive material with a low electron affinity is a material deposited in amorphous form. Such a device may find particular application to electron guns or display devices.
Claims16
Field-emission device comprising:
- at least one planar cathode made of a conductive material, the at least one planar cathode including,
- a central region having a first surface material with a low electron affinity, and
- a flanking region located about said central region and having a second surface material with a higher electron affinity than the first surface material,
- wherein the conductive material is a material deposited in an amorphous form.
Process for producing a field-emission device, comprising:
- producing on a planar substrate the following successive layers including,
- an amorphous layer made of a first surface material having a low electron affinity,
- a dielectric layer, and
- a conducting layer;
- producing a mask on an assembly of the successive layers so as to mask a central region and a peripheral region of the successive layers and to leave an intermediate region of the successive layers free of the mask;
- etching the successive layers in the intermediate region;
- removing the mask;
- forming a planar cathode from the amorphous layer by removing in the central region the conducting layer and the dielectric layer to expose said first surface material;
- and
- forming a flanking region about said central region, said flanking region formed by converting an outer part of the exposed first surface material into a second surface material having a higher electron affinity than the first surface material.
Process for producing a field-emission device, comprising:
- producing on a planar substrate the following successive layers,
- an amorphous layer having a first surface material with a low electron affinity,
- a high electron affinity layer including a second surface material having an electron affinity higher than the first surface material,
- a dielectric layer, and
- a conducting layer;
- producing a mask on the successive layers so as to leave a masked region, corresponding to an area of a planar cathode to be produced, free of the mask;
- and
- forming the planar cathode from the amorphous layer by etching a part of the successive layers in the masked region, except for the amorphous layer, thereby forming on the planar cathode a flanking region including the higher electron affinity layer.
Dependencies are inferred from the claim text.