Low-temperature packaging through Ag-Cu supersaturated solid solution nanoparticle paste for high-temperature power electronics.

• Anti-oxidative Ag-20 at. % Cu solid solution nanoparticles were obtained. • A dense supersaturated joints with in situ precipitates and twins were obtained. • High-temperature shear strengths were increased by 66.5% at 400 ℃. • The shear strength was increased by 97.4 % after aging at 300 ℃ for 500 h. In this work, anti-oxidative single-phase Ag-Cu supersaturated solid-solution nanoparticles (Ag-Cu SS-NPs) were synthesized by a one-step method to serve as packaging materials for high-temperature power electronics. After sintering at 250 ℃ in air, a dense supersaturated structure with nano-sized Cu precipitates and coherent twins, high shear strength over 133 MPa and low resistivity (4.35 μΩ·cm) were obtained. Notably, the supersaturated structure with nano-sized Cu precipitates enhanced the thermomechanical properties and high-temperature stability. The high-temperature shear strengths of the sintered Ag-Cu joints reached remarkable 93.5 MPa at 300 ℃. Meanwhile, the room-temperature shear strength of the sintered Ag-Cu SS-NP joints after aging at 300 ℃ for 500 h was maintained at 98.7 MPa, doubling that of the sintered Ag joints. Hence, the Ag-Cu SS-NP paste presents excellent feasibility and potential for high-temperature power electronics. [ABSTRACT FROM AUTHOR]