Thermal Annealing Properties of Nb--Al/AlO sub x -Nb Tunnel Junctions

The increase of the normal-state resistance of Nb--Al/AlO sub x --Nb tunnel junctions by annealing at elevated temperatures is reported. Junctions with an area of 4 mu m exp 2 or smaller have been investigated. The resistance could be increased up to a factor of five with only a small influence on t...

Full description

Saved in:
Bibliographic Details
Published in:Journal of applied physics 1992-10, Vol.72 (7), p.3165-3168
Main Authors: Lehnert, T, Billon, D, Grassl, C, Gundlach, K H
Format: Article
Language:English
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The increase of the normal-state resistance of Nb--Al/AlO sub x --Nb tunnel junctions by annealing at elevated temperatures is reported. Junctions with an area of 4 mu m exp 2 or smaller have been investigated. The resistance could be increased up to a factor of five with only a small influence on the quality of the quasiparticle characteristic. The effect can be used to adjust the resistance after fabrication. The increase of the AlO sub x barrier thickness has been estimated. Annealing experiments in nitrogen atmosphere and after nitridation have been carried out to find out from where the additional oxygen stems. The annealing properties of anodization curves have been investigated. A clear increase of the oxide peak could be observed. The results also show that the resistance is sensitive to temperature increases in the various fabrication steps.
ISSN:0021-8979