High quality factor nanocrystalline diamond micromechanical resonators limited by thermoelastic damping

We demonstrate high quality factor thin-film nanocrystalline diamond micromechanical resonators with quality factors limited by thermoelastic damping. Cantilevers, single-anchored and double-anchored double-ended tuning forks, were fabricated from 2.5 mu m thick in-situ boron doped nanocrystalline diamond films deposited using hot filament chemical vapor deposition. Thermal conductivity measured by time-domain thermoreflectance resulted in 24 +/- 3 W m(-1) K-1 for heat transport through the thickness of the diamond film. The resonant frequencies of the fabricated resonators were 46 kHz-8MHz and showed a maximum measured Q approximate to 86 000 at f(n) = 46.849 kHz. The measured Q-factors are shown to be in good agreement with the limit imposed by thermoelastic dissipation calculated using the measured thermal conductivity. The mechanical properties extracted from resonant frequency measurements indicate a Young's elastic modulus of approximate to 788 GPa, close to that of microcrystalline diamond. (C) 2014 AIP Publishing LLC.