Fully micromechanical piezo-thermal oscillators

This work presents thermally actuated micromechanical resonant structures capable of self-sustained oscillation without the need for supporting electronic circuitry. This is enabled by interactions between thermal actuation and the piezoresistive effect in such structures leading to an internal positive feedback mechanism. Single crystal silicon extensional mode dual plate resonators with frequencies in the few MHz range (as high as 6.6MHz) have been fabricated to demonstrate this concept. Such devices can initiate self-sustained oscillations under both vacuum and atmospheric pressure by passing only a DC bias current through them. Output voltage peak to peak amplitudes as high as 825mV, with power consumption in the few mili-Watts range, have been demonstrated for such self-sustained oscillators. Preliminary jitter measurements show promising results.