Thermal conductance enhancement of particle-filled thermal interface materials using carbon nanotube inclusions

Thermal interface materials (TIMs) are widely used in high power integrated circuits. This work introduces multi-walled carbon nanotubes (CNTs) into a silicone composite filled with metal particles, resulting in a TIM with higher thermal conductivity. Anomalous increase in thermal conductivity is found starting at a CNT volume fraction of 1.4% for a composite filled with 40% nickel particles and at 2.2% for a composite filled with 30% nickel particles. The measured thermal conductivities are interpreted using closed-form models to account for the interactions between the CNTs and the metal particles, interactions which can be characterized by the percolation theory. The results reported here are promising for developing TIMs with higher thermal conductivities and better compliance and wetting properties.