Individually switched field emission arrays

Patent metadata

Field	Value
Publication number	US-9748071-B2
Application number	US-201414765759-A
Country	US
Kind code	B2
Filing date	Feb 5, 2014
Priority date	Feb 5, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

An electron beam apparatus is disclosed that includes a plurality of current source elements disposed in at least one field emitter array. Each current source element can be a gated vertical transistor, an ungated vertical transistor, or a current controlled channel that is proximate to an optically-modulated current source. The electron beam apparatus includes a plurality of field emitter tips, each field emitter tip of the plurality of field emitter tips being coupled to a current source element of the plurality of current source elements. The electron beam apparatus is configured to allow selective activation of one or more of the current source elements.

First claim

What is claimed is:

1. An electron beam apparatus comprising:
a substrate;
a plurality of field emitter elements disposed over the substrate in at least one array, each field emitter element of the plurality of field emitter elements comprising:
a current channel region disposed at a first end of the field emitter element proximate to the substrate;
a donor-doped region or an acceptor-doped region disposed at a second end of the field emitter element that is different from the first end; and
a field emitter tip disposed proximate to the second end of the field emitter element;

and
at least one extraction gate electrode disposed proximate to the plurality of field emitter elements, to apply a potential difference proximate to at least one field emitter tip of the plurality of field emitter elements, thereby accelerating the electrons emitted from the at least one field emitter tip in a direction away from the at least one field emitter tip,
wherein each field emitter element of the plurality of field emitter elements further comprises a conductive material surrounding at least a portion of a side of the respective field emitter element.

2. The apparatus of claim 1 , wherein each field emitter element of the plurality of field emitter elements has an aspect ratio of height to lateral dimension of about 5:1, about 10:1, about 50:1, about 100:1, about 200:1, about 500:1 about 800:1, about 1000:1, or about 5,000:1.

3. The apparatus of claim 1 , wherein the plurality of field emitter elements are disposed at a pitch of about 45 microns, about 40 microns, about 30 microns, about 20 microns, about 15 microns, about 10 microns, about 5 microns, about 2 microns, or about 1 micron.

4. The apparatus of claim 1 , wherein the array is a one-dimensional array, a two-dimensional array, or a staggered three-dimensional array.

5. The apparatus of claim 1 , wherein each field emitter tip has a radius of about 1 nm, about 2 nm, about 3 nm, about 5 nm, about 8 nm, about 10 nm, about 12 nm, about 15 nm, or about 20 nm.

6. The apparatus of claim 1 , wherein the emitted electrons from the plurality of field emitter elements produce an electron beam of brightness about 1×10 6 A/cm 2 /sr, 5 ×10 6 A/cm 2 /sr, 1×10 7 A/cm 2 /sr, 5×10 7 A/cm 2 /sr, 1×10 8 A/cm 2 /sr, about 5×10 8 A/cm 2 /sr, about 1×10 9 A/cm 2 /sr, or about 5×10 9 A/cm 2 /sr.

7. The apparatus of claim 1 , wherein each field emitter element comprises silicon, aluminum, copper, silver, gold, platinum, zinc, nickel, titanium, chromium, palladium, tungsten, molybdenum , diamond, carbon nanofiber, graphene, indium-tin-oxide, or gallium arsenide.

8. The apparatus of claim 1 , wherein each field emitter tip comprises an electrically conductive material.

9. The apparatus of claim 8 , wherein each field emitter tip comprises a refractory metal, a noble metal, a semiconductor, a semimetal, or a semimetal.

10. The apparatus of claim 1 , wherein each field emitter element has a pillar structure, and wherein the pillar structure has a length of about 10 microns and a lateral dimension of about 100 nm.

11. The apparatus of claim 1 , wherein a donor-doped region is disposed at the second end of the field emitter element, and wherein a voltage can be applied to the conductive material to regulate an amount of a current flowing through the channel region to the donor-doped region of the respective field emitter element.

12. The apparatus of claim 1 , wherein the at least one extraction gate electrode is a plurality of extraction gate electrodes, and wherein each extraction gate electrode of the plurality of extraction gate electrodes is disposed proximate to a respective one or more field emitter elements of the plurality of field emitter elements to apply the potential difference proximate to the respective one or more field emitter elements of the plurality of field emitter elements.

13. The apparatus of claim 12 , wherein each extraction gate electrode of the plurality of extraction gate electrodes is formed as a conductive material layer including a hollow opening that is disposed proximate to the one or more field emitter tips of the respective one or more field emitter elements.

14. The apparatus of claim 13 , wherein the conductive material layer is disposed proximate to the respective one or more field emitter elements such that the hollow opening is substantially concentric with a portion of at least one field emitter tip of the respective one or more field emitter elements of the plurality of field emitter elements.

15. The apparatus of claim 13 , wherein the hollow opening is substantially circular, substantially oval, or substantially polygonal in shape.

16. The apparatus of claim 12 , further comprising at least one electrostatic electrode disposed proximate to the plurality of extraction gate electrodes, to shape the electrons accelerated by the at least one extraction gate electrode into at least one focused electron beam.

17. The apparatus of claim 16 wherein the at least one electrostatic electrode comprises a plurality of electrostatic electrodes, and wherein each electrostatic electrode of the plurality of electrostatic electrodes is disposed proximate to a respective extraction gate electrode of the plurality of extraction gate electrodes.

18. The apparatus of claim 16 , wherein the at least one electrostatic electrode is at least one of: an electron focusing lens assembly, an additional extraction gate electrode, an Einzel lens, an acceleration grid, and a stigmation corrector.

19. The apparatus of claim 1 , wherein the substrate comprises at least one electrically conductive contact region, and wherein the plurality of field emitter elements are in electrical communication with the at least one electrically conductive contact region of the substrate.

20. The apparatus of claim 1 , wherein the substrate comprises at least one logic chip, and wherein the plurality of field emitter elements are in electrical communication with the at least one logic chip.

21. The apparatus of claim 20 , wherein a donor-doped region is disposed at the second end of the field emitter element, wherein each field emitter element of the plurality of field emitter elements further comprises a conductive material surrounding at least a portion of a side of the respective field emitter element, and wherein the at least one logic chip controls a current or voltage applied to the conductive material of each field emitter element to regulate an amount of a current flowing through the channel region to the donor-doped region of the respective field emitter element.

22. An electron beam apparatus comprising:
a substrate comprising an optically modulated current source;
a plurality of field emitter elements disposed over the substrate in at least one array, each field emitter element of the plurality of field emitter elements comprising:
a current channel region disposed at a first end of the field emitter element proximate to the optically modulated current source; and
a field emitter tip disposed proximate to a second end of the field emitter element that is different from the first end; and

at least one extraction gate electrode disposed proximate to the plurality of field emitter elements, to apply a potential difference proximate to at least one field emitter tip of the plurality of field emitter elements, thereby accelerating electrons emitted from the at least one field emitter tip in a direction away from the at least one field emitter tip;
where

Assignees

• Massachusetts Inst Technology

Inventors

• Guerrera Stephen Angelo
• Akinwande Akintunde I

Classifications

• H10P95/00

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• H01J2237/063

  Electron sources · CPC title

• H01J2237/0473

  accelerating · CPC title

• H01J37/3174

  Particle-beam lithography, e.g. electron beam lithography · CPC title

• H01J37/3007

  Electron or ion-optical systems · CPC title