Effect of antimony on vigorous interfacial reaction of Sn–Sb/Te couples

A vigorous reaction between molten Sn–Sb solder and Te substrate leads to a thick SnTe–Sn mixture layer at the soldered junction. The effect of Sb addition in Sn on the kinetics of Sn–Sb/Te interfacial reaction and formation of SnTe–Sn reaction layer is reported. Sb element was found to expedite the growth of SnTe–Sn reaction layer in the Sn–Sb/Te couples dramatically. With increasing Sb content in Sn–Sb solder, the growth rate of SnTe–Sn reaction layer increases while both the size of SnTe grains and the fraction of Sn in SnTe–Sn decrease. The thickness of SnTe–Sn layer follows a parabolic law with reaction time for Sn–Sb/Te couples, unlike the linear dependence with time for Sn/Te couples. An apparent diffusivity of 2 × 10−7 cm2/s was determined for Sn transport through the SnTe–Sn layer in the Sn–Sb/Te couples reacting at 250 °C.

Research highlights
► A tiny Sb addition in Sn can expedite the growth of interfacial reaction layer in Sn–Sb/Te reaction couples.
► Growth kinetics of SnTe–Sn interfacial reaction layer in Sn–Sb/Te reaction couples is mainly controlled by Sn diffusion through the reaction layer.
► The presence of Sb in Sn solder can lead to the formation of SbSn phase that serves as nucleation agents for SnTe nuclei.