Interface behavior and electrical properties of Zn–Sn–Cu (CTZ) stacking layer films with thermal diffusion and electrically induced crystallization

In this study, a Zn–Sn–Cu sandwich structure was heated and electrically crystallized. The morphology, phase structure, diffusion behavior, and interface electrical properties of the sandwich structure and the microstructure changes in Zn, Sn, and Cu driven by heat and electricity were investigated. The experimental results revealed that thermal effects caused marked diffusion of Cu atoms. Cu₆Sn₅ IMC was formed at the Cu–Sn interface, and Cu₅Sn₈ was formed at the Zn–Sn interface. The electron flow drove Sn atoms into Cu with directional diffusion and inhibited Cu₆Sn₅ formation. Moreover, the overall electrical properties, interlayer thickness, and microstructure differences varied with the diffusion behavior and interface composition caused by thermal and electrical effects.