A CMOS-MEMS arrayed RGFET oscillator using a band-to-band tunneling bias scheme

In this work, a CMOS-MEMS arrayed resonant gate field effect transistor (RGFET) oscillator is demonstrated for the first time. With the mechanically coupled array approach and deep submicron gap spacing, the proposed resonator with Q of 1,800 under purely capacitive transduction achieves the record-low motional impedance R
_m
of 1.1 kΩ among all CMOS-MEMS resonators. By using the FET readout, a CMOS-MEMS arrayed RGFET oscillator is realized through a closed-loop configuration, demonstrating phase noise performance of -96 dBc/Hz at 1 kHz offset and -122 dBc/Hz at far-from-carrier offset, respectively. In particular, a novel band-to-band tunneling bias scheme is employed for the proposed CMOS-MEMS RGFET without the need of manual switch charging or complicated biasing circuits. The proposed device is fabricated by a standard 0.35 μm CMOS process together with a maskless release process.