title: Bimodal sintered silver nanoparticle paste with ultrahigh thermal conductivity and shear strength for high temperature thermal interface material applications.
abstract: A bimodal silver nanoparticle (AgNP) paste has been synthesized via the simple ultrasonic mixing of two types of unimodal AgNPs (10 and 50 nm in diameter). By sintering this paste at 250 °C for 30 min, we obtained an ultrahigh thermal conductivity of 278.5 W m(-1) K(-1), approximately 65% of the theoretical value for bulk Ag. The shear strength before and after thermal cycling at 50-200 °C for 1000 cycles was approximately 41.80 and 28.75 MPa, respectively. The results show that this excellent performance is attributable to the unique sintered structures inside the bimodal AgNP paste, including its low but stable porosity and the high density coherent twins. In addition, we systematically discuss the sintering behavior of this paste, including the decomposition of the organic layers and the formation of the coherent twins. On the basis of these results, we confirm that our bimodal AgNP paste has excellent potential as a thermal interface material for high temperature power device applications.
authors.affiliation: State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, People's Republic of China.
authors.forename: Mingyu
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, People's Republic of China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yu
keywords: bimodal size distribution; silver nanoparticles; sintering; thermal conductivity; thermal interface material; twin formation