Characterization of microelectromechanical HF resonators fabricated using a SOI-based low temperature process

This paper reports on the characterization of electromechanical high frequency resonators realized using a novel SOI-based low temperature fabrication process. Key features of the devices are single crystal silicon resonant beams, 200 nm to 600 nm thin transducer gaps, and gold electrodes. The fabrication process combines bulk silicon micromachining applying deep reactive ion etching, low temperature deposition of a thin sacrificial oxide and electroplating of the lateral electrodes. The resonant behavior of devices with resonance frequencies f_res between 420 kHz and 4.11 MHz was characterized as a function of the bias voltage V_bias applied to the beam. Measurements were performed at ambient pressures p between 5×10^-5 mbar and 0.5 mbar. Q values up to 52,000 at f_res=420 kHz and 6,000 at f_res=4.11 MHz were obtained. The interaction of resonator and measurement setup were simulated using an electrical network simulation program combined with a finite element analysis using ANSYS^®.