Title :
A temperature-stable mems oscillator on an ovenized micro-platform using a PLL-based heater control system
Author :
Zhengzheng Wu ; Rais-Zadeh, Mina
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Univ. of Michigan, Ann Arbor, MI, USA
Abstract :
In this work, an oxide-refill process is used to null the first-order temperature coefficient of frequency (TCF) of silicon MEMS resonators and to achieve high thermal resistance isolation structures. The technology enables fabrication of a low-power ovenized micro-platform on which multiple MEMS devices can be integrated. The intrinsic frequency-temperature characteristic of two resonators is utilized for temperature sensing, and closed-loop oven control is realized by phase-locking two MEMS oscillators at a specific temperature. PLL-based control circuitry is implemented in 0.18 μm CMOS to interface with the MEMS resonators. The ovenized MEMS oscillator exhibits an overall frequency drift of ± 5.5 ppm over -40 °C to 70 °C. The MEMS oscillator exhibits near zero phase noise degradation in closed-loop operation.
Keywords :
CMOS integrated circuits; closed loop systems; elemental semiconductors; integrated circuit noise; micromechanical resonators; oscillators; ovens; phase locked loops; phase noise; silicon; temperature control; thermal resistance; MEMS devices; PLL-based control circuitry; PLL-based heater control system; closed-loop oven control; first-order temperature TCF; first-order temperature coefficient-of-frequency; intrinsic frequency-temperature characteristic; low-power ovenized microplatform; near-zero phase noise degradation; ovenized MEMS oscillator; oxide-refill process; phase locking; silicon MEMS resonators; size 0.18 mum; temperature -40 degC to 70 degC; temperature sensing; temperature-stable MEMS oscillator; thermal resistance isolation structure; Frequency measurement; Micromechanical devices; Oscillators; Resonant frequency; Silicon; Temperature measurement; Thermal resistance;
Conference_Titel :
Micro Electro Mechanical Systems (MEMS), 2015 28th IEEE International Conference on
Conference_Location :
Estoril
DOI :
10.1109/MEMSYS.2015.7051078
