Diffusivity and atomic mobility in fcc Cu–Mn–Si alloys: measurements and modeling by CALTPP program

Accurate diffusivities and atomic mobility parameters of fcc Cu–Mn–Si alloys are essential to understand the growth behavior of Mn barrier layer between the Cu interconnect and Si-based dielectric in microelectronic integrated circuits. Totally twelve diffusion couples of fcc Cu–Mn–Si alloys at 923, 1023 and 1123 K are prepared and their composition profiles are determined by EPMA technique. The composition profiles are input in CALTPP program to extract the interdiffusivity matrices by the Matano–Kirkaldy method (version 1) and numerical inverse approach (version 2). Then, the corresponding atomic mobilities are evaluated based on these two versions of diffusivities, respectively. The quality of these two versions of atomic mobility parameters is examined by comparing the diffusion behaviors between the model-predicted and measured ones. In the current work, atomic mobilities of version 2 are recommended on account of their better consistency with composition profiles. The three-dimensional main interdiffusion coefficients, activation energy and frequency-factor planes of fcc Cu–Mn–Si alloys are constructed to display the composition- and temperature-dependent diffusion properties. The reliable atomic mobility parameters obtained in this work are key input for the computation design for multi-component Cu alloys.