Microelectronic field emission device with air bridge anode

• US 5,136,205 A
• Filed: 03/26/1991
• Issued: 08/04/1992
• Est. Priority Date: 03/26/1991
• Status: Expired due to Term

• Current Assignee: Microelectronics Technology Inc (MTI Laboratory Inc)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Sokolich, Marko, Bardai, Zaher
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Patel, Ashok
• Application Number:
  US07/675,590
• Time in Patent Office: 497 Days
• Field of Search: 313/309, 313/308, 313/310, 313/336, 313/351
• US Class Current: 313/309
• CPC Class Codes: H01J 21/105 with microengineered cathode and control electrodes, e.g. Spindt-type
• CPC Class Codes: H01J 3/022 with microengineered cathode, e.g. Spindt-type
• CPC Class Codes: H01J 9/025 of field emission cathodes

Abstract

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.

Claims

1. A vacuum field emission device, comprising:

a substrate;

an array of field emission tips on said substrate;

a plurality of rows of conductive air bridges spanning the array of field emission tips and spaced therefrom, the air bridges being laterally spaced from each other and having sufficient clearance above the field emission tips to enable establishment of a uniform vacuum during operation of the vacuum field emission device; and

conductor means connected to the field emission tips and conductive air bridges for conducting respective voltage differentials between the air bridges and the field emission tips sufficient to induce a current flow between them;

wherein the air ridges are spaced about 2-5 microns above the field emission tips.

2. The field emission device of claim 1 wherein the air bridges are each about 5-15 microns wide, about 100 microns long and adjacent air bridges are laterally spaced from each other by about 2-10 microns.