Fabrication and Characterisation of Resistive Nanocrystalline Graphite

This work demonstrates the feasibility of fabricating resistive nanocrystalline graphite (NCG) on a Si substrate. The NCG film thickness of 9 nm was deposited using metal-free plasma enhanced chemical vapour deposition (PECVD) on a 6-inch p-type silicon wafer. The surface and electrical properties of the resistors produced were investigated. The average grain size of the NCG thin film is 35 nm with 0.8 nm of surface roughness. The electrical characterization of the NCG strips show metal-like behaviour in which the resistance is proportional to the strip lengths. The sheet resistance is found to be 39 kohm/sq which is two orders of magnitude larger than graphene deposited using Chemical Vapour Deposition. This indicates the carrier transport across grain boundaries has a large influence on the overall resistance of the device. However, the nano-sized grains on the NCG material could be used to enhance the sensitivity of the material towards the environment.