Method of making microelectronic field emission device with air bridge anode

• US 5,181,874 A
• Filed: 04/08/1992
• Issued: 01/26/1993
• Est. Priority Date: 03/26/1991
• Status: Expired due to Fees

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Bardai, Zaher, Sokolich, Marko
• Primary Examiner(s): Ramsey, Kenneth J.
• Application Number:
  US07/865,384
• Time in Patent Office: 293 Days
• Field of Search: 445/24, 445/25, 445/50, 445/, 156/656, 156/661.1
• US Class Current: 445/24
• 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 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.

Claims

1. A method of making a field emission device, the field emission device comprising a substrate, an array of field emission tips on the substrate and a plurality of rows of conductive air bridges spanning the array of field emission tips, wherein the air bridges are formed by the process comprising the steps of:

depositing a first layer of photoresist over the substrate covering the field emission tips;

forming openings in the first layer, the openings having the shape and spacing of the air bridges;

forming a metallic membrane over the openings to form a plating base for the air bridges;

forming a second layer of photoresist over the substrate covering the metallic membrane and exposed portions of the first layer;

forming second openings in the second layer, the second openings having the shape and spacing of the air bridges and exposing portions of the metallic membrane;

forming a metal layer over the second openings; and

removing the remaining portions of the first and second layers.