Effect of Ge doping on electrochemical migration of SAC alloys in 0.5 M NaCl solution

Abstract

Electrochemical migration (ECM) behavior of three lead-free alloys: Sn3Ag0.5Cu (SAC305) as a reference, SAC305+0.1Ge, and SAC0305+0.1Ge was investigated in 0.5 M NaCl solution at two voltage levels, 3 and 10 VDC to assess the effect of Ge doping on ECM behavior of high Ag and low Ag content SAC alloys. The results of the water drop (WD) test have shown that Ge doped alloys showed significantly lower Mean-Time-To-Failure (MTTF) values than the reference at both voltage levels. Furthermore, using scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS) methods, the morphology of the formed dendrites in Ge doped alloys showed a tree-like structure, while elemental composition showed germanium was not detected and only tin was the main migration element.