Carbon sp2-on-sp3 Technology: Graphene-on-Diamond Devices and Interconnects
- Author(s): Yu, Jie
- Advisor(s): Balandin, Alexander
- et al.
Graphene demonstrates potential in practical applications due to its excellent electronic and thermal properties. Typical graphene field-effect transistors and interconnects built on conventional SiO2/Si substrates reveal a breakdown current density on the order of 1 uA/nm2 (i.e. 10^8 A/cm2) which is approximately 100 times larger than the fundamental limit for metals, but still smaller than the maximum achieved in carbon nanotubes. In this dissertation research I investigated different methods of fabricating graphene devices and interconnects on synthetic diamond and tested their current-voltage and thermal characteristics. Several types of these graphene-on-diamond devices have been compared to graphene-on-SiO2/Si devices as a baseline reference. It was established that by replacing SiO2 with synthetic diamond one can substantially increase the current carrying capacity of graphene to a level as high as ~18 uA/nm2 in ambient conditions. The obtained results indicate that graphene's current-induced breakdown is thermally activated. It was also found that the current carrying capacity of graphene can be improved not only on single-crystal diamond substrates, but also on inexpensive ultrananocrystalline diamond (UNCD). Additionally, UNCD can be produced in low-temperature processes compatible with conventional Si technology which is attributed to the decreased thermal resistance of ultrananocrystalline diamond layers at elevated temperatures. The obtained results are important for graphene's applications in interconnects and transistors and can lead to the new planar sp2-on-sp3 carbon-on-carbon technology.