A Fast-Startup Self-Sustained Thermal-Piezoresistive Oscillaror with >10⁶ Effective Quality Factor In The Air

Abstract

This paper reports a self-sustained thermal-actuation piezoresistive-detection oscillator with boosted startup time and quality (Q) factor in the order of a million. A high Q-factor is an essential property for resonant sensors to achieve a high signal to noise ratio. It is demonstrated that the thermal-piezoresistive effect can increase the Q-factor. We obtained an effective Q-factor up to 1.06 million operating in air with direct-current induced self-oscillation. Furthermore, a fast startup time is achieved when stimulating the self-sustained oscillator with a current just below the threshold of self-oscillation requirements. The experimental results show that the startup time can be decreased by a factor of ~3 by initially thermally preexpanding the actuating nanobeam compared to a coldstartup condition.

Silicon Carbide-on-Insulator Thermal-Piezoresistive Resonator for Harsh Environment Application

“…To implement the thermal-piezoresistive effect in SiC, we propose a resonator based on a SiCOI platform with a negative piezoresistive coefficient. The SiCOI thermalpiezoresistive resonator is comprised of two symmetrical suspended masses connected by a narrow piezoresistive beam and supported by four spring beams [14]. Figure 1(a) shows the finite element model of the SiC resonator oscillating in its in-plane mode.…”