Hughes Aircraft Company

Other

Zaher Bardai

Robert T Longo

Arthur E Manoly

Ralph Forman

Randy K Rolph

Marko Sokolich

Mario A Barillas

Arlene E Lamb

A field emission device employs an anode in the form of an air bridge spanning the tip of a field emission cathode. The anode is supported only at its opposite ends, leaving the area under the air bridge open. An array of cathode emitters employ a series of parallel, laterally spaced anode air bridges, with each air bridge spanning a line of cathodes. The lateral spacing between the air bridges facilitates both the removal of underlying photo-resist during fabrication, and the establishment of a uniform vacuum if desired. The clearance between the anode and cathode is substantially less than previously obtainable, resulting in a significant reduction in both size and in the anode's operating voltage level. Fabrication of the air bridge anodes can be integrtaed with the remainder of an integrated circuit.

Method of making microelectronic field emission device with air bridge

A field emission device employs an anode in the form of an air bridge spanning the tip of a field emission cathode. The anode is supported only at its opposite ends, leaving the area under the air bridge open. An array of cathode emitters employ a series of parallel, laterally spaced anode air bridges, with each air bridge scanning a line of cathodes. The lateral spacing between the air bridges facilitates both the removal of underlying photoresist during fabrication, and the establishment of a uniform vacuum if desired. The clearance between the anode and cathode is substantially less than previously obtainable, resulting in a significant reduction in both size and in the anode's operating voltage level. Fabrication of the air bridge anodes can be integrated with the remainder of an integrated circuit.

Microelectronic field emission device with air bridge anode

Outgassed materials liberated in spaces between pointed field emitter tips and an electrode structure during electrical operation of a field emitter device are vented through passageways to a pump or gettering material provided in a separate space. The passageways may include channels formed through an insulating layer between a base for the field emitters, and the electrode structure, with the channels interconnecting adjacent spaces in a row direction. Where the electrode structure includes a gate electrode layer and an anode layer, similar channels may be formed through an insulator layer provided therebetween. The field emitters may be formed in an arrangement of rows and columns, with the spacing between the columns smaller than the spacing between the rows. Holes are formed by anisotropic etching through the anode, gate electrode, and insulator layers down to the base. Subsequent isotropic etching of the insulator layers through the holes in the anode and gate electrode layers is controlled to cause sufficient undercutting in the insulator layers that adjacent holes merge together only in the row direction to form the channels.

Field emitter structure and fabrication process providing passageways

Outgassed materials liberated in spaces between pointed field emitter tips and an electrode structure during electrical operation of a field emitter device are vented through passageways to a pump of gettering material provided in a separate space. The passageways may include channels formed through an insulating layer between a base for the field emitters, and the electrode structure, with the channels interconnecting adjacent spaces in a row direction. Where the electrode structure includes a gate electrode layer and an anode layer, similar channels may be formed through an insulator layer provided therebetween. The field emitters may be formed in an arrangement of rows and columns, with the spacing between the columns smaller than the spacing between the rows.

Field emitter structure providing passageways for venting of outgassed

A plurality of field emitters in the form of hollow, upstanding pointed cones or pyramids formed by a molding process extend from a surface of an electrically conductive layer. An electrically conductive mesh is adhered to an opposite surface of the conductive layer by a high temperature brazing process in electrical connection with the conductive layer. The mesh provides a strong metal base with good thermal conductivity for mounting. Additional elements such as a gate and anode structure may be formed on the conductive layer in alignment with the field emitters to form a field emitting triode array or the like.

Field emitter structure and fabrication process

Conical field emitter elements are formed on a surface of a substrate after which a layer of metal is deposited on top of the substrate surface and over the field emitter elements. A layer of oxide is then deposited over the metal layer. Another layer of metal is deposited over the layer of oxide to form a gate metal layer. A layer of photoresist is then deposited over the gate metal layer. The layer of photoresist is then plasma etched in an oxygen atmosphere to cause portions of the photoresist above respective field emitter elements to be removed and provide self-aligned holes in the photoresist over each of the field emitter elements. The size of the holes may be controlled by appropriately controlling process parameter, including plasma etching time and power and/or initial photoresist thickness. The exposed gate metal layer is etched using the layer of photoresist as a mask. The photoresist layer is removed, and the layer of oxide is etched to expose the field emitter elements. Another oxide layer and an anode metal layer also may be formed over the gate metal layer to produce a self-aligned triode structure.

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Torrance, CA, United States of America

Zaher Bardai