A CMOS-MEMS Beam Resonator with Q > 10,000

This work for the first time demonstrates a Q up to 11,450 in a flexural CC-beam resonator based on a CMOS-MEMS process platform. In particular, the CC-beam resonator employs the Q-enhancement stepped structure along the beam length to introduce stress dilution to address the low Q issue dominantly limited by the material loss in the CMOS-MEMS process. With a theoretically predicted dilution factor D
Q
up to 3.8×, the measured Q of a stress-engineered stepped CC-beam resonator shows a similar improvement of 3.2× compared to that of regular counterparts. This technique not only avoids the typical post-fabrication annealing process but also overturns the low Q impression of CMOS-MEMS based devices.