Effects of Fast Temperature Cycling on Aluminum and Gold Metal Systems

Microwave power transistors in a radar-system may undergo ~ 1011 fast heating and cooling cycles during lifetime. Controlled temperature cycling tests have been carried out on Al, passivated Al, and gold metallization systems using both a special test pattern and commercially available transistors. Significant visible and electrical changes were observed for Al, glassed Al and a laboratory Ta-Pt-Ta-Au system, but not for a commercial gold transistor.