Electrically conductive thermal interface materials based on vertically aligned carbon nanotubes mats

In power microelectronics, the trends towards miniaturization and higher performances result in higher power densities and more heat to be dissipated. In most electronic assembly, thermal interface materials (TIM) help provide a path for heat dissipation but still represent a bottleneck in the total thermal resistance of the system. VA-CNTs mats are typically grown on HR silicon substrate with Al₂O₃ diffusion barrier layer using Thermal CVD process. In many cases, “die attach” thermal interface materials need to be electrically conductive and the growth of dense VA-CNT mats on an electrically conductive substrate remains a challenge. This paper presents the growth of dense VA-CNT mats on doped silicon with Al₂O₃ and TiN diffusion barrier layer. Processes, thermal and electrical characterization of VA-CNTs based thermal interface materials are studied and reported.