High quality factor nanocrystalline diamond micromechanical resonators limited by thermoelastic damping

Abstract

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 μm 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–8 MHz and showed a maximum measured Q ≈ 86 000 at fn = 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 ≈788 GPa, close to that of microcrystalline diamond.

High frequency torsional-mode nanomechanical resonators enabled by very thin nanocrystalline diamond diaphragms

“…As device dimensions scale down for applications that require higher sensitivity or higher speed, thin films of diamond have been grown by techniques such as microwave plasma chemical vapor deposition (MPCVD) [5,6], or hot filament chemical vapor deposition (HFCVD) [7,8], showing material properties comparable to single crystal diamond. Resonant structures based on polycrystalline, nanocrystalline, and ultrananocrystalline diamond films have been explored [8][9][10][11][12][13][14][15][16][17], demonstrating both high frequency (HF) and high quality (Q) factor resonators.…”

Diamond as a material for monolithically integrated optical and optomechanical devices

“…Thermoelastic dissipation is Table 1 Relevant material properties for a variety of materials suitable for integrated optomechanics and nanophotonics, namely the band gap E g , transparency range TR, refractive index n, Young's modulus E, thermal conductivity k, density r, and the sound velocity c. found to be much lower compared to equally sized resonators in materials like silicon. This can be linked to diamond's high thermal conductivity [21]. In comparison with silicon, diamond nanomechanical resonators have been shown to yield substantially lower mechanical dissipation with quality factors (Q factors) in excess of several million at low temperature [22].…”

Diamond as a Platform for Integrated Quantum Photonics

“…Besides its versatile optical properties, diamond also offers outstanding mechanical properties, in particular an exceptionally high Young's modulus of 1100 GPa. Together with low thermo‐elastic dissipation due to its high thermal conductivity, this enables mechanical resonators operating at high frequencies without suffering from significant damping . In particular, for high precision sensing applications this is of utmost interest .…”