US 9,852,870 B2 · Method for the fabrication of electron field emission devices including carbon nanotube field electron emisson devices

Abstract

The present invention is directed to a method for the fabrication of electron field emitter devices, including carbon nanotube (CNT) field emission devices. The method of the present invention involves depositing one or more electrically conductive thin-film layers onto a electrically conductive substrate and performing lithography and etching on these thin film layers to pattern them into the desired shapes. The top-most layer may be of a material type that acts as a catalyst for the growth of single- or multiple-walled carbon nanotubes (CNTs). Subsequently, the substrate is etched to form a high-aspect ratio post or pillar structure onto which the previously patterned thin film layers are positioned. Carbon nanotubes may be grown on the catalyst material layer. The present invention also described methods by which the individual field emission devices may be singulated into individual die from a substrate.

Drawings

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Drawings

Claims65

Dependent claims

A method of fabricating an electron field emission device using micro- and/or nano-fabrication techniques, the method comprising:

selecting a first material substrate that is electrically conductive,
depositing onto the first material substrate a second material layer that is electrically conductive,
depositing onto a surface of the second material layer a third material layer that is electrically conductive,
patterning and etching the third material layer into a first predefined shape and dimensions,
patterning and etching the second material layer into a second predefined shape and dimensions,
defining a pattern for an etch of a third predefined shape and dimensions into the first material substrate,
performing the etch of the third predefined shape and dimensions into the first material substrate to a predefined depth to form a pillar or post,
heating the first material substrate to a predefined temperature, whereby the third material layer re-forms into a predefined shape suitable for carbon nanotube growth, and
growing at least one carbon nanotube on the third material layer to a predefined height.

6 more elements

Dependencies are inferred from the claim text.

Description8,700 words

Summary574 words

#The present invention is directed to a method for the fabrication of electron field emitter devices, including carbon nanotube (CNT) field emission devices. These devices have application in any product or system employing electron beams or sources, including: electron-beam imaging; electron-beam lithography; field electron spectroscopy; electron-gun sources; atomically shaped emitter tips; electron-beam sensing; etc. These devices can be implemented as single field emitter devices or as arrays of field emitter devices, even very large arrays of field emitter devices. The present invention is applicable to the implementation of any electron-beam field emitter structure, with or without the employment of carbon nanotubes as the field emitter of electrons. The present invention allows large field emitter arrays to be implemented for faster through-put electron-beam imaging and electron-beam lithography.

#Electron field emission is an emission of electrons induced by external electromagnetic fields. Field emission can happen from solid and liquid surfaces, or individual atoms into vacuum or open air, or result in promotion of electrons from the valence to conduction band of semiconductors.

#Field emission in pure metals occurs in high electric fields: the gradients are typically higher than 1000 volts per micron and strongly dependent upon the work function of the metal. Electron sources based on field emission have a number of applications, including electron sources for high-resolution electron microscopes and electron-beam lithography. Field emission is explained by quantum tunneling using the Fowler-Nordheim equations.

Brief description of the drawings7 figures

#FIG. 1 is an illustration of a field emission device with a carbon nanotube emitter according to the invention.

#FIG. 2 is an illustration of an array of field emission devices with carbon nanotube emitters according to the invention.

#FIG. 3 is an illustration of a field emission device without carbon nanotubes according to the invention.

Detailed description7,991 words

#The present invention is directed to a method for the fabrication of carbon nanotube (CNT) electron field emitter devices. These devices have application in any product or system using electron beams including: electron-beam imaging; electron-beam lithography; field electron spectroscopy; electron-gun sources; atomically sharp emitter tips; electron-beam sensing; and many more. These devices can be implemented as single field emitters or as arrays of field emitters, even very large arrays of field emitters, including but not limited to arrays of tens, hundreds, thousands, millions, or tens of millions of emitters, or more. The present invention is applicable to the implementation of any electron-beam field emitter structure, with or without the employment of carbon nanotubes as an emitter of electrons. The present invention allows large field emitter arrays to be implemented for fast throughput electron-beam imaging, electron-beam lithography that have application in semiconductor fabrication, as well as many other important applications.

#Field emission in pure metals occurs in high electric fields: the gradients are typically higher than 1000 volts per micron and strongly dependent upon the work function of the metal. Electron sources based on field emission have a number of applications, including electron sources for high-resolution electron microscopes and electron-beam lithography. Field emission can be analytically modeled by quantum tunneling using the Fowler-Nordheim equations.

Facts

Application

13/113,378Filed 23 May 2011

Published

US 2012/0301981 A129 Nov 2012

Granted

26 Dec 2017

Term ends

23 Jan 2033

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 611 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification7 codes

H01J 1/304
Cold cathodes, e.g. field-emissive cathode: field-emissive cathodes
B82Y 10/00
Nanotechnology for information processing, storage or transmission
B82Y 40/00
Manufacture or treatment of nanostructures
H01J 9/025
Of cold cathodes: of field emission cathodes

Timeline

23 May 2011Application filedUS 13/113,378
30 Jun 2011Assigned to Corporation for National Research Initiativesassignment of assignor's interest
29 Nov 2012PublishedUS 2012/0301981 A1
26 Dec 2017GrantedUS 9,852,870 B2
12 Oct 2026TodayWithin its term
23 Jan 2033Term endsEstimated, includes 611 days of adjustment

Method for the fabrication of electron field emission devices including carbon nanotube field electron emisson devices

Life of this patent

Method for the fabrication of electron field emission devices including carbon nanotube field electron emisson devices

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims65

Description8,700 words

Drawings

Classification7 codes

Life of this patent

Description8,700 words