Mechanical characterisation of nanocrystalline graphite using micromechanical structures

• PECVD used to deposit nanocrystalline graphite films directly onto Silicon wafers
• Microstructures are fabricated from the film to show potential for MEMS/NEMS
• Material Young's modulus of 23 GPa is characterised from the microstructures
• This represents a large scale, reproducible method for nanographite MEMS

Conductive nanocrystalline graphite has been deposited using plasma-enhanced chemical vapour deposition at 750 °C, directly onto silicon substrates without any catalyst and fabricated into micromechanical membrane and beam structures. Using the buckling profile of the membrane and beam structures, we measure a built-in strain of − 0.0142 and through wafer-bow measurement, a compressive stress of 436 MPa. From this we have calculated the Young's modulus of nanographite as 23.0 ± 2.7 GPa. This represents a scalable method for fabricating nanographite MEMS and NEMS devices via a microfabrication-compatible process and provides useful mechanical properties to enable design of future devices.

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