Browse Prior Art Database

Forming of Conductive Paths in an Insulating Material

IP.com Disclosure Number: IPCOM000081701D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Laibowitz, RB: AUTHOR [+3]

Abstract

A technique is described wherein selective doping and heat treatment significantly lower the resistance of an insulating material, by providing high-conductivity filamentary paths. These paths can then be used as a switchable resistor or for other characteristics, such as superconducting weak links.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

Forming of Conductive Paths in an Insulating Material

A technique is described wherein selective doping and heat treatment significantly lower the resistance of an insulating material, by providing high- conductivity filamentary paths. These paths can then be used as a switchable resistor or for other characteristics, such as superconducting weak links.

If an amorphous or fine-grained polycrystalline material is formed at a low temperature, it can be heavily doped above the solubility limit with some other component during growth. If this amorphous material is then crystallized by the application of heat by electric field or by optical absorption, the impurity will be deposited in internal surfaces such as grain boundaries. With a suitable choice of materials, low-resistance paths will thus be formed, e.g., with Bi in Nb(2)O(5).

Many amorphous and fine grain polycrystalline films can be made impure by doping with a material that is insoluble in the host matrix. These metastable films can be produced in many ways - sputtering, coevaporation, ion implanting, anodizing, vapor transport, etc. The example which is to be described here is Nb(2)O(5). A cathode for sputtering is prepared of Nb(2)O(5) with a predetermined amount of Bi inclusions. Alternatively, a powdered cathode with the same ingredients can be used, bismuth oxide can replace the pure Bi. The film prepared from such a source will be Bi doped Nb(2)O(5) with the Bi held metastably in the Nb(2)O(5) matrix, which is the starting material for the example of this technique and resulting device.

The starting material is then treated by causing crystallization to take place for amorphous starting materials, or by annealing for polycrystalline and single- crystal films. This can be done by placing the material between electrodes and applyin...