Temperature Compensation in Silicon-Based Micro-Electromechanical Resonators

In this paper, we present passive temperature compensation by means of silicon dioxide. Using an oxide refilling technique it avoids gap distance reduction and therefore prevents degradation of electromechanical coupling and motional resistance of the micro-electromechanical resonator. Samples are fabricated and electrically characterized to demonstrate the feasibility of the process concept. A constant quality factor (Q) and only a slight increase of the series resistance value (R_m) are achieved, while the frequency inaccuracy due to temperature variation is reduced. ANSYS simulations are carried out to evaluate the potential of the technique, resulting in a remaining inaccuracy of less than 40 ppm.