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.

Automated summary

Accurate diffusivities and atomic mobility parameters are crucial for understanding the growth behavior of Cu-Mn-Si alloys in microelectronic integrated circuits. In this study, diffusion couples of fcc Cu-Mn-Si alloys were prepared at different temperatures and their composition profiles were determined. The interdiffusivity matrices and atomic mobilities were extracted using computational methods and compared with experimental results. The obtained atomic mobility parameters are recommended for the computation design of multi-component Cu alloys.