Thermoelastic damping in micromechanical resonators

We show that the dominant energy loss mechanism in plate modes of a 1.5 mu m thick silicon micromechanical resonator is thermoelastic damping. In situ ultra-high vacuum annealing lowers the dissipation of two neighboring resonance modes (460 and 510 kHz) at 120 K to Q(-1)< 5x10(-7). From 120 to 400 K, the Q(-1) of these modes increase at different rates, in quantitative agreement with a modification (that accounts for mode shape) of Zener's theory of thermoelastic damping.