An ultra-low power ovenized CMOS-MEMS resonator monolithically integrated with interface circuits

This work reports on the design, fabrication, and characterization of the first CMOS-MEMS ovenized micromechanical resonator monolithically integrated with interface circuits while attaining a 100°C effective temperature rise under heating power in a sub-mW range. The key to attaining such low heater power consumption (i.e., high heating efficiency) relies on the combination of low thermal-conductivity nature of constituent materials and high thermal-isolation structural design. The serpentine-shaped heater structure consists of thick SiO₂ structural layer and thin polysilicon heater, hence offering very high thermal resistance well suited for low power operation. An arrayed free-free beam oxide resonator is placed near the heater and operated in a typical two-port configuration to serve as an ovenized resonant tank. Furthermore, with 2-mW heating power, the heater structure generates visible light, exhibiting its temperature greater than 1000°C and verifying the superior thermal isolation using CMOS-MEMS technology.