A 2.47 GHz ultra NanoCrystaline diamond disk resonator with temperature compensation for RF application

This paper presents a 2.47 GHz capacitively transduced micromechanical disk resonator based on a Wine Glass mode of vibration. An ultra nano-crystalline diamond (UNCD) material has been used to achieve high frequency-quality factor (f.Q) product for RF applications, since this material provides highest young´s modulus up to 1000 GPa and therefore highest acoustic velocity of 15000 m/s. Mode shape and frequency of the device has been confirmed first by numerical modeling and thereafter simulated using COMSOL multyphysics. COVENTORWARE has been used to simulate fabrication flow of the structure. Furthermore, this disc resonator device is shown to be temperature compensated achieving TCF of 2.5 ppm/K with TiO₂ dielectric coating and TCF of 8.5 ppm/K for SiO₂ dielectric coating.