2013 Volume 54 Issue 7 Pages 1155-1159
This study presents an electrical current testing that is based on the Sn–xAg–0.5Cu (x = 1, 3 mass%) photovoltaic (PV) ribbon, and investigates the growth mechanism of the intermetallic compounds (IMCs). The microstructure of both alloy solders contains the eutectic region (β-Sn+Cu6Sn5+Ag3Sn) and the base phases (β-Sn). The eutectic phases in the Sn–3Ag–0.5Cu (SAC305) alloy presented a continuous distribution, and its amount was higher. After soldering, the Cu6Sn5 and Ag3Sn IMCs were found at the interfaces, and their morphologies were dominated by Ag contents in the Sn–Ag–Cu (SAC) solder. The whole interfacial characteristics of IMCs were affected after biasing for 40 h. The growth behavior of these IMCs was controlled by the bias-induced thermal diffusion mechanism and the evolution of IMC morphology was dominated by the growth dynamics. The IMCs, formed at the interfaces (SAC/Cu, SAC/Ag), dominated the series resistance of the PV ribbon.