Microcrystalline diamond micromechanical resonators with quality factor limited by thermoelastic damping

Thin-film microcrystalline diamond micromechanical resonators with mechanical quality factor limited by thermoelastic dissipation in the diamond film are demonstrated. Surface micromachined double ended tuning fork resonators were fabricated from in-situ boron doped microcrystalline diamond films deposited using hot filament chemical vapor deposition. Time-domain thermoreflectance measurements show thermal conductivity of 110 W m⁻¹ K⁻¹ for heat transport through the thickness of the diamond film. Measurement of the quality factor of resonators spanning a frequency range 0.5–10 MHz shows a maximum Q = 81 646 and demonstrates good agreement with quality factor limited by thermoelastic dissipation using 100 W m⁻¹ K⁻¹ for the in-plane thermal conductivity of the diamond film.