Browse Prior Art Database

Very High Density RAM

IP.com Disclosure Number: IPCOM000113710D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Briska, M: AUTHOR [+2]

Abstract

A read/write memory of atomic dimensions can be carried out by use of a MeX crystal-type of material, where Me is transition metal such as Nb, Ta, Ti, etc. and X is chalcogene such as S, Se, etc.

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Very High Density RAM

      A read/write memory of atomic dimensions can be carried out by
use of a MeX crystal-type of material, where Me is transition metal
such as Nb, Ta, Ti, etc. and X is chalcogene such as S, Se, etc.

      In the Figure a NbS[2]  cristal is positioned in a vacuum
chamber with a partial pressure of carbon monoxide gas of approx.

10(-5)  mm Hg.  The CO gas is ionized by an electron gun in order to
produce a negative CO-plasma which will be preferentially adsorbed on
the Nb-atomic layers by an electrical voltage addressed locally by
means of Scanning Tunneling Microscopy (STM) needles.  A further set
of STM needles with a lower voltage can read out this information
without destroying the CO-deposit.  Applying different voltages,
positive or negative, the CO-deposits can be removed and built at
other places, thus obtaining a read/write behaviour of a Random
Access Memory.  Memory refresh time can be prolonged applying low
temperature of liquid nitrogen, for example, which suppresses the
volatility of the CO-deposits.

      Instead of CO-deposit, carbon crack products from hydrocarbon
plasma can be formed on the Nb-atomics layers.  These deposits are
non-volatile at room temperature thus minimising the need for refresh
cycles.