A CMOS-MEMS arrayed RGFET

To greatly enhance the performance of our previously developed CMOS-MEMS resonant gate field effect transistor (RGFET) [1], a novel CMOS-MEMS RGFET array which combines a metal/oxide composite resonant-gate arrayed structure and a FET arrayed transducer has been proposed for the first time utilizing the TSMC 0.35 μm CMOS technology together with a series of maskless wet etching processes. To resemble the function of a normal transistor, a “floating gate operation” was adopted to activate the transistor working at its saturation region. With proper drive and bias conditions, the measured transmission shows a resonance with Q around 1,000 and the signal-to-feedthrough ratio greater than 30 dB under a direct two-port measurement setup. As compared to the purely capacitive readout, the arrayed RGFET exhibits a 19-dB enhancement in terms of the insertion loss. With such a decent result, we do believe the CMOS-MEMS arrayed RGFET would bring simplicity and performance enhancement due to one transistor configuration for the future MEMS oscillator applications.