摘要
In this paper, we present the design and characterization of monolithically integrated complementary metal oxide semiconductor (CMOS) micromachined accelerometers utilizing polysilicon piezoresistors. Despite their lower piezoresistive effect compared to their single-crystal counterpart, we achieve enhanced sensitivity by implementing thin support beams to amplify the piezoresistive change upon detection. To facilitate a comprehensive comparison, three designs with proof mass sizes of 100 &null 100, 150 &null 150, and 200 &null 200 &null <sup>2</sup> and a proof-mass thickness of 8.3 &null were fabricated. These designs were realized using a 0.35 &null CMOS process followed by post-CMOS wet etching processes. The measured results revealed out-of-plane resonant frequencies of 8.125, 4.015 and 2.260 kHz for the respective designs. The 200-&null design exhibited the highest sensitivity, measuring 317.7 &null for out-of-plane acceleration, while the 100-&null design demonstrated a sensitivity of 38.6 &null Additionally, the 200-&null design displayed a sensing resolution of 15 mg, accompanied by a temperature dependence of -2.60 &null The results demonstrate the promising potential of CMOS piezoresistive accelerometers for various sensing applications.