*Jonathan Ho, Ping-Yen Hsieh, Ju-Liang He, Feng Chia University, Taichung City, Taiwan
With the continuous development of communication technology, meeting the effective thermal dissipation requirements for 5G-related products and high-power electronic devices are facing huge challenges. One way to solve this problem is to apply heat spreading materials, which can efficiently transport massive heat away from hotspot, thereby reducing the core temperature. In our previous study, graphene film with a unique 3D hierarchical architecture coexisting an in-plane oriented graphene layer and an out-of-plane oriented graphene structure can be prepared by high power impulse magnetron sputtering (HIPIMS) on copper foil making a 50% improved thermal diffusivity. Further increased deposition time resulted in a decreased thermal diffusivity due to the deteriorated crystallinity of the growing graphene film. Herein, introducing copper as a gaseous catalyst to facilitate consecutive high-quality HIPIMS-graphene film growth was demonstrated. In addition, this study also verifies that thick and massive HIPIMS-graphene film with unique 3D hierarchical architecture give a further improved thermal spreading capability with an ultimate thermal diffusivity value of 1.21 cm2/s. The success in thick graphene growth by incorporating copper may bring a step further toward advanced thermal management application for 5G-related products and high-power electronic devices.