TCF-Tailoring Vertically Stepped Structures for Temperature Insensitive CMOS-MEMS Resonators

This work demonstrates a temperature compensation scheme using a vertically stepped structure in CMOS-MEMS technology. Particularly, a temperature coefficient of frequency (TCF) tailoring structure composed by stacking metal layers with specifically designed lengths help a metal Al CC-beam resonator yields linear compensation that reduces the first-order TCF
1
from an uncompensated -374.5 ppm/°C to -1.45 ppm/°C with a TCF
2
of -1.09 ppm/°C
²
from -20 °C to 85 °C. Further, polarization voltage tuning across the temperature range, which is based on the resonance frequency read-out of a typical CC-beam resonator as a temperature sensor, achieves parabolic compensation and reduces the overall frequency deviation from 3,309 ppm to 210 ppm from the temperature range of -20 °C to 85 °C.