Massively parallel array cathode

• US 5,363,021 A
• Filed: 07/12/1993
• Issued: 11/08/1994
• Est. Priority Date: 07/12/1993
• Status: Expired due to Term

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: MacDonald, Noel C.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US08/089,821
• Time in Patent Office: 484 Days
• Field of Search: 315/366, 315/304, 315/309, 315/351, 313/422, 313/336
• US Class Current: 315/366
• CPC Class Codes: H01J 3/022 with microengineered cathode, e.g. Spindt-type
• CPC Class Codes: H01J 31/127 using large area or array sources, i.e. essentially a source for each pixel group
• CPC Class Codes: H01J 9/025 of field emission cathodes

Abstract

A massively parallel electron beam array for controllably imaging a target includes a multiplicity of emitter cathodes, each incorporating one or more micron-sized emitter tips. Each tip is controlled by a control electrode to produce an electron stream, and its deflection is controlled by a multielement deflection electrode to permit scanning of a corresponding target region.

Claims

1. A massively parallel electron beam array, comprising:

a substrate;

a multiplicity of submicron emitter tips fabricated from said substrate for producing corresponding electron emission streams, said tips being separated into a plurality of groups of one or more, each group being electrically isolated from all remaining groups, said groups comprising a plurality of cathodes;

an emitter control electrode for each of said multiplicity of emitter tips for controlling corresponding emitter electron emission streams;

a cathode control electrode for each of said plurality of cathodes for producing from the electron emission streams of each cathode a corresponding single cathode beam, said plurality of cathodes producing an array of beams;

a target for receiving said array of beams, each beam striking a corresponding target region whereby each target region is illuminated by a corresponding beam; and

a deflector for said cathode array for deflecting all of said beams of said array simultaneously with respect to said target.

2. The array of claim 1, wherein each said emitter tip is fabricated from a single crystal silicon substrate the tip comprising a post which is integral with and extends upwardly from the substrate, the top of the post being tapered to form a tip having a diameter less than 20 nm.

3. The array of claim 2, wherein each said post has a resistance of about 5 Mohm.

4. The array of claim 1, wherein the spacing between each of said multiplicity of tips is about 80 μ

m.

5. The array of claim 1, wherein each said tip is coated with a low work function material.

6. The array of claim 1, wherein said deflector includes said substrate mounted for mechanical motion in an xy plane.

7. The array of claim 1, wherein said deflector includes reduction optics for said array of beams.

8. The array of claim 7, wherein said cathode control electrodes are located to permit scanning of each said cathode beam with respect to its corresponding target region.

9. The array of claim 1, wherein said emitter control electrode for each of said tips comprises focusing means for each said stream.

10. The array of claim 1, wherein said emitter control electrode for each of said tips comprises means for scanning each of said emission streams.

11. The array of claim 1, wherein said deflector for scanning said array of beams simultaneously includes means for mechanically moving said cathodes in a plane defined by said cathodes.

12. The array of claim 1, wherein said emitter control electrode comprises a first metal layer surrounding said emitter tips.

13. The array of claim 12, wherein said cathode control electrode comprises a second metal layer surrounding said emitter tips and spaced from said first layer.

14. The array of claim 12, wherein said deflector comprises a plurality of metal electrodes surrounding each said emitter tip and spaced above said first tip.

15. The array of claim 14 further including control means for selectively energizing said control electrode and said deflector electrodes for each emitter tip for controlling the electron stream produced by each said tip.