Browse Prior Art Database

Scanning Tunneling Microscope As Ion Emitter

IP.com Disclosure Number: IPCOM000108458D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 83K

Publishing Venue

IBM

Related People

Avouris, P: AUTHOR [+3]

Abstract

References (1) and (2) teach how to use the technology developed for the scanning tunneling microscope (STM) to write fine lines on substrates using electrons from the STM tip (when it acts as a field emitter) to break apart molecules in the gas phase or on the surface. The products of molecular breakup can then be used to fabricate features with dimensions in the nanometer range for a wide variety of technological uses.

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Scanning Tunneling Microscope As Ion Emitter

       References (1) and (2) teach how to use the technology
developed for the scanning tunneling microscope (STM) to write fine
lines on substrates using electrons from the STM tip (when it acts as
a field emitter) to break apart molecules in the gas phase or on the
surface.  The products of molecular breakup can then be used to
fabricate features with dimensions in the nanometer range for a wide
variety of technological uses.

      This article teaches that with positive bias potential the STM
tip can function as field ion source and as a source of high enough
field to autoionize gas phase molecules.  In such operation the STM
technology can be used for nanometer structure fabrication,
lithography, mask  or circuit repair, shallow local implantation,
etc.

      We use the fact that most of the atoms and molecules undergo
ionization in high electric fields of 2-5 V/Ao (3). This phenomenon
is well known and used in Field Ion Microscopy (4).  Electric fields
of 2-5 V/Ao can easily be established between the STM tip and the
substrate; therefore, molecules can effectively be field ionized.
The field ionized species will impact the substrate, with kinetic
energy controlled by the potential applied between the tip and the
substrate, and may react with the surface or may be implanted into
it.  The feasibility of this idea has been demonstrated by close
space operation of liquid metal ion emitters (LMIEs) (5).  LMIEs,
however, can provide only ions from a few low melting point metals;
therefore, their use is rather limited.  STMs as Ion Emitters, on the
other hand, can provide a wide variety of ions merely by the
appropriate choice of the gas phase composition ensuring a highly
flexible operation.

      The preferred embodiment of this invention is then to run the
scanning tunneling microscope over th...