Improved thermal conductivity by vertical graphene contact formation for thermal TSV

This paper reports the tailoring thermal conductivity of novel dense vertical and horizontal graphene (DVHG) structures, which we previously discovered. By removing horizontal graphene layers, resulting in forming vertical graphene contacts to the electrode, we not only improved the thermal conductivity by a factor of 10 but also improved the electrical conductivity by a factor of 100. The pyrolytic graphite, grown at a higher temperature than the DVHG, showed a high thermal conductivity of 1426 W/mK by forming vertical graphene contacts. Although the DVHG showed poor thermal properties at this point, we found that the vertical graphene contact formation can be an important technology to realize high thermal conductivity for carbon-based thermal through-silicon-vias (TSV).