Thick-film gold and platinum conducing paths for high temperature electronics

A new thick film gold conductive composition for high temperature electronics was elaborated and tested. This paste was designed for metallization of the alumina substrates (Al2O3) for electrical interconnection system, e.g. for a silicon carbide Schotky diode. Also platinum pastes for conductive paths resistant to high temperatures (over 600 degrees C) were elaborated by the authors. Several gold and platinum powders and glasses, as well as bonding oxides were examined to design a suitable composition. The influence of the paste composition and firing temperature on the layer properties was shown. The obtained layers were aged a 1000 hours at elevated temperatures (350 degrees C). Sheet resistance of platinum and gold paths was measured. Mechanical strength and electrical resistance of wire bonds to the gold layers after aging were also examined. The electrical measurements were performed at room temperature and elevated temperature (150 degrees C, 250 degrees C, 350 degrees C), using precise four-wire method. The microstructure of layers was also shown.