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Indentation Induced Ohmic Contact to Silicon

IP.com Disclosure Number: IPCOM000120957D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 69K

Publishing Venue

IBM

Related People

Clarke, DR: AUTHOR [+3]

Abstract

A technique is described whereby ohmic contact to silicon is formed by loads placed upon contact metallurgy. Described is a semiconductor fabrication process that transforms silicon to a metal phase when a load is applied. Removal of the load results in a loss of ohmic contact.

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Indentation Induced Ohmic Contact to Silicon

      A technique is described whereby ohmic contact to silicon is
formed by loads placed upon contact metallurgy.  Described is a
semiconductor fabrication process that transforms silicon to a metal
phase when a load is applied.  Removal of the load results in a loss
of ohmic contact.

      Although in prior art, a diamond indentation has been found to
alter the conductivity of silicon, it was concluded that diamond
indentation locally transformed high resistivity (104L-cm2) Si into
highly conducting Si, therefore, the conductivity must be metallic.
Experiments have been repeated on n- and p- type, N10L -cm Si and
similar conclusions have been reached.

      However, by using the more conducting Si, it was observed that
the metal/metallic Si/semiconducting-Si contact is ohmic.  The large
spreading resistance associated with the small contact area on the
relatively resistive substrates means that the specific resistivity
of the contact cannot be accurately determined, except to place an
upper limit of N10-4L-cm2 on its value (for n-type Si). Both prior to
loading and after, the metal- semiconductor contact is rectifying.
Reloading in the same position returns the ohmic contact.  Silicon
hardness below 450~C is sufficient to allow pressure to produce the
metallic phase in a non-hydrostatic environment.

      When the ohmic contact was performed on n-GaAs, no metallic
conductivity or ohmic contact was observe...