On-Chip High Quality Factor CMOS-MEMS Silicon-Fin Resonators

An in-plane CMOS-MEMS fully differential silicon-fin resonator (SiFR), operating as a cantilever beam at free-clamp mode with a center frequency of 8.04 MHz, quality factor (Q) of 3589, and insertion loss of 33.6 dB is introduced. The resonator was fabricated directly on a conventional CMOS substrate with an on-chip differential amplifier. To enhance the Q, a 2-step silicon etch is employed to harness the high material Q of silicon substrate resulting in more than three times Q enhancement than that of previous CMOS-MEMS resonators.