Transduction comparison of a resonant transducer realized in a commercially available CMOS-MEMS platform

Abstract

In this paper, we report the comparison of different transduction mechanisms, including (i) purely capacitive drive/sense, (ii) capacitive drive/piezoresistive sense, and (iii) thermal drive/piezoresisitve sense, through a simple resonant transducer achieved in a commercially available platform (CMOS 0.18μm technology). To perform a fair comparison, capacitive combs and poly resistors are adopted to provide various combinations of the drive and sense configurations. The experimental results show performance of the thermal drive/piezoresistive sense is superior to that of other transductions under a typical circuit biasing (1.8V). By characterizing randomly picked 8 samples, the 1-σ frequency variation is lower than 4,800 ppm with total drive/sense power consumption below 0.67 mW through the (iii) scheme. Moreover, a high Q-factor of 200 is also measured in air (under 760 Torr), which successfully demonstrates its great potential for future portable sensor nodes application.