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ElectroComponent Science and Technology
Volume 4 (1977), Issue 3-4, Pages 205-211

Influence of the Metal Migration From Screen-and-Fired Terminations on the Electrical Characteristics of Thick-Film Resistors

1Magneti Marelli, Divisione Sistemi ed Elettronica, Via F. Filzi, 1, Pavia 27100, Italy
2Cselt, Sezione Componenti e Materiali, Via G. Reiss Romoli, 274, Torino 10148, Italy
3Istituto di Fisica dell'Universitità, Laboratorio di Elettronica, Via Vivaldi, 70, Modena 41100, Italy

Received 20 June 1977

Copyright © 1977 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The electrical characteristics of ruthenium-based thick-film resistors with different conductive terminations (PtAu and Ag based compositions) and with different aspect ratios were examined. The purpose is to understand the effects of resistivity decrease and TCR variation caused by the migration of metal particles from the terminations into the resistor film.

The majority of the data were collected by using silver-based terminations since Ag diffusion processes, and then the relevant electrical effects, are emphasized.

Scanning electron microscopy, electron microprobe analysis and X-ray diffraction analysis have been used to analyze the diffusion processes and the thick-film microstructures. It is shown that the experimental data is simply explained by a conduction model which assumes percolative tunneling of electrons through conductive grains embedded in the glass matrix of the resistors. Using simple hypotheses the model theory gives a good quantitative fit of the experimental results.