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

摘要

The electrical characteristics of ruthenium-based thick-film resistors with different conductive terminations (PtAuand Ag based compositions) and with different aspect ratios were examined. The purpose is to understand the effectsof resistivity decrease and TCR variation caused by the migration of metal particles from the terminations into theresistor film.The majority of the data were collected by using silver-based terminations since Ag diffusion processes, and thenthe relevant electrical effects, are emphasized.Scanning electron microscopy, electron microprobe analysis and X-ray diffraction analysis have been used toanalyze the diffusion processes and the thick-film microstructures. It is shown that the experimental data is simplyexplained by a conduction model which assumes percolative tunneling of electrons through conductive grainsembedded in the glass matrix of the resistors. Using simple hypotheses the model theory gives a good quantitativefit of the experimental results.