Graphene is a one-atom-thick material with unusual and highly promising for applications electrical [1] and thermal [2] properties. First obtained by mechanical exfoliation from graphite, graphene is now efficiently grown by chemical vapor deposition (CVD) on copper (Cu) films. It was reported that layered graphene - metal composites have enhanced mechanical strength. However, it was not known how deposition of graphene on Cu films affects their thermal properties.

In this talk we will report of our investigation of thermal properties of graphene coated Cu films. The measurements were performed using the modified “laser flash” technique, which allowed for investigation of the in-plane heat conduction properties. It was found hat CVD of graphene enhances the thermal diffusivity and thermal conductivity of graphene coated Cu films. Deposition of graphene increased the thermal conductivity K of 9-μm (25-μm) thick Cu films by up to 24% (16%) near the room temperature.

Interestingly, the increase of thermal conductivity of graphene coated Cu films is primarily due to changes in Cu morphology during graphene deposition and associated with it temperature treatment. Graphene’s action as an additional heat conducting channel was small due to its small thickness as compared to that of Cu films. Enhancement of thermal properties of metal films via graphene coating may lead to major changes in metallurgy and graphene applications in hybrid graphene - Cu interconnects in Si complementary metal-oxide-semiconductor (CMOS) technology.

[1] K.S. Novoselov et al. “Electric field effect in atomically thin carbon films,” Science, 306, 666 (2004);

[2] A.A. Balandin, et al., “Superior thermal conductivity of single-layer graphene," Nano Letters, 8, 902 (2008).

The work at UC Riverside was supported, in part, by the National Science Foundation (NSF) project ECCS-1307671 on engineering thermal properties of graphene, by DARPA Defense Microelectronics Activity (DMEA) under agreement number H94003-10-2-1003, and by STARnet Center for Function Accelerated nanoMaterial Engineering (FAME) - Semiconductor Research Corporation (SRC) program sponsored by MARCO and DARPA.

Pradyumna Goli

UC Riverside

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