本研究主要討論p型和n型Bi2Te3熱電材料與擴散阻障層Ni-P在電遷移效應下之界面反應。電流效應與Peltier效應為影響介金屬化合物之主要因素。銲料SAC305與p型和n型Bi2Te3熱電材料接合後，在不同電流密度與不同溫度下進行測試。Bi2Te3材料係以火花電漿燒結(SPS)技術所製成，且在其表面與銲料間鍍上擴散阻障層Ni-P。 實驗結果顯示，Ni-P可防止多孔性之脆性化合物SnTe的生成，在經過長時間的實驗條件下之後，Ni-P仍然可保有其完整之界面，此性質為維持銲接點可靠度之重要因素。另外，在SAC305/Ni-P與Ni-P/p, n-Bi2Te3界面中觀察到(Cu, Ni)6Sn5 和NiTe的生成。從反應時間與化合物生長厚度之關係結果可發現，此兩種化合物不僅有明顯之成長，且在陰極與陽極分別有不同的厚度。而從化合物之主要擴散元素反應機制可得知，在低電流密度之下，陰陽極兩端主要受到電子擴散通量方向的影響；當通過高電流密度時，Peltier效應則主導了熱電系統中介金屬化合物之生成。 This study investigates electromigration in Bi2Te3 thermoelectric (TE) material systems and the effectiveness of the diffusion barrier under current. The influences of the interfacial reaction by electromigration and Peltier effect were decoupled in this research. n- and p-type Bi2Te3 were connected to SAC305 solders and different current densities at various temperatures were applied. The Bi2Te3 samples were fabricated by the Spark Plasma Sintering (SPS) technique and electroless Ni-P was deposited at the solder/TE interfaces. The results elucidate the importance of the Ni diffusion barrier to the joint reliability. Different intermetallic compound (IMC) layers including (Cu, Ni)6Sn5 and NiTe formed at solder/Ni-P and Ni-P/substrate interfaces, respectively. The results show that the mechanism of compound growth was dominated by electromigration at low current density and dominated by Peltier effect at high current density.
