Study on Micro-silver Joint Doped with Silicon Carbide Nanowires for Power Electronics

Sintered Ag paste is considered as a promising die-attach material for the packaging in the power electronics, because it has great electrical and thermal conductivity as well as excellent mechanical properties. In this paper, the influence of minor silicon carbide nanowires (SiC NWs) addition on the mechanical properties and the microstructures of micro-Ag paste pressureless sintered at different temperatures are investigated. The preheating parameter of the specimens is set to 130 °C for 10 min, which is contributing to the evaporation of organic solvents in order to achieve a better sintered structure. The results demonstrate that as the sintering temperature increases from 250 °C to 300 °C, the shear strength of Ag sintered joints rises from 38.93 MPa to 43.44 MPa under the same sintering time. After doping SiC nanowires, the shear strength of composite Ag-SiC joint is better than the pure Ag joints at different sintering temperatures. The shear strength of Ag joint added with SiC nanowires is up to 41.95 MPa and 45.98 MPa under 250 °C and 300 °C for 30 min, respectively. What’s more, the fracture morphology shows that the sintered Ag structure produces plastic deformation in both Ag joint and composite Ag-SiC joint. Moreover, it is obvious that the SiC NWs nail at the porous Ag structure, which is beneficial to prohibiting the dislocation motion in sintered Ag layer. Thus, SiC NWs addition to micro-Ag paste can improve the mechanical performance of sintered Ag joint. It is hoped that this research can provide theoretical support for the application of micro-Ag paste applied to high power electronic devices.