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Copper Germanide Passivating Low Resistivity Contacts to High Tc Superconductors

IP.com Disclosure Number: IPCOM000103852D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Krusin-Elbaum, L: AUTHOR [+2]

Abstract

At the present time, one of the most severe problems in preparation of high temperature superconductors is obtaining long-term reproducible surface properties. This is an issue, since for most applications, good low resistivity ohmic contacts are essential. In the case of YBaCuO, it loses oxygen at the surface when exposed to air at room temperature after high temperature (900ºC) anneal in oxygen. Even after lower temperature processing, the surface can be modified over a period of time. This process can produce an insulating or nonsuperconducting surface layer which may result in a barrier leading to a non-ohmic contact. A simple metal contact layer is inadequate since in itself it can deplete the surface of oxygen and form metal oxides. In the case of

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Copper Germanide Passivating Low Resistivity Contacts to High Tc Superconductors

      At the present time, one of the most severe problems in
preparation of high temperature superconductors is obtaining
long-term reproducible surface properties.  This is an issue, since
for most applications, good low resistivity ohmic contacts are
essential.  In the case of YBaCuO, it loses oxygen at the surface
when exposed to air at room temperature after high temperature
(900ºC) anneal in oxygen.  Even after lower temperature
processing, the surface can be modified over a period of time.  This
process can produce an insulating or nonsuperconducting surface layer
which may result in a barrier leading to a non-ohmic contact.  A
simple metal contact layer is inadequate since in itself it can
deplete the surface of oxygen and form metal oxides.  In the case of

BiSrCaCuO or TlCaBaCuO, the addition of oxygen can be detrimental and
the decrease in the transition temperature depends on the annealing
temperature, the warm-down time and the ambient in which it takes
place.  Clearly, a scheme to lock the oxygen in high-'T'sub c films
and stabilize the surface, would be extremely valuable, especially if
it is compatible with the strategy for the Si-technology in devices
as well as in packaging.

      Disclosed is a method for using 'Cu'sub 3Ge as a low
resistivity contact to high 'T'sub c materials, which can be formed
at room temperature and certainly below 200ºC, and which is
extremely effective in preventing the out-diffusion and in-diffus...