Effect of thermoelastic damping on silicon, GaAs, diamond and SiC micromechanical resonators

Abstract

The effect of thermoelastic damping as a main dissipation mechanism in single crystalline silicon, GaAs, diamond, SiC and SiO2 micromechanical resonators are studied. Numerical simulation is performed to compare quality factors of the given materials. Results using Zener’s well-known approximation and recent developments of Lifshitz and Roukes models were used to model thermoelasticity effects. In the later model, the effect of thermal diffusion length is taken into account for determination of thermoelastic damping. Our results show that larger discrepancy is obtained between the two models for SiO2. The difference is pronounced when beam aspect ratio (L/w) is smaller. Such progresses will find potential applications in optimal design of high quality factor micrometer- and nanometer-scale electromechanical systems.

Next Generation Design and Prospects for Cannex

“…The actual excitation signal is regulated by a feedback circuit maintaining the signal level. With respect to frequency shift measurements, silicon with its low thermoelastic damping coefficient [204] and large elastic modulus [205] is advantageous, as it offers a high mechanical quality factor Q ∼ 10 4 [49] and, thereby, a small detection bandwidth f BW ≈ 3 mHz. On the other hand, the large Q-factor implies long integration times τ ∼ (2π f BW ) −1 .…”