- 期刊
Interfacial Reactions between Sn and Ag-Coated Bi_2te_3-Based Elements
並列摘要
Excessive growth of the SnTe phase at the thermoelectric (TE) solder joint is a big concern because a thick intermetallic compound (IMC) may embrittle the solder joint. Introduction of a diffusion barrier is a method commonly used to inhibit excessive IMC growth. Assessment of silver (Ag) as a diffusion barrier in the TE solder joints was performed by investigating the interfacial reactions between tin (Sn) and bismuth telluride (Bi2Te3)-based elements coated with a Ag layer using electroplating. Two types of Bi_2Te_3-based TE elements, Bi_2(Te,Se)_3 and (Bi,Sb)_2Te_3, were fabricated by casting and examined using powder X-ray diffractometer (XRD). Two types of reactions including liquid/solid Sn/TE and solid/solid Sn/TE reactions at 250℃(30~120 s) and 150℃(24~120 h), respectively, were conducted and the intermetallic compound formation and interfacial microstructures were examined using X-ray energy dispersive spectrometer and scanning electron microscopy (SEM). The experimental results indicated that Ag was not a suitable diffusion barrier for the Bi_2(Te,Se)_3 solder joint because its insertion enhanced the growth of the SnTe phase. On the contrary, excessive growth of the SnTe phase in the (Bi,Sb)_2Te_3 solder joint was effectively inhibited by inserting a Ag layer, which showed good diffusion barrier property for Ag in the (Bi,Sb)_2Te3 solder joint.