Localized thermal oxidation for frequency trimming and temperature compensation of micromechanical resonators

This work demonstrates electronically controllable frequency trimming and temperature compensation of individual single crystalline silicon thermal-piezoresistive resonators via localized self-induced thermal oxidation. Frequency trimming as high as ~3.7% has been demonstrated using this technique for a 53MHz resonator. At the same time, the formed oxide layer using this technique can significantly suppress the temperature coefficient of frequency (TCF) for such resonators. TCF values as low as 0.2 ppm/°C have been demonstrated for resonators with initial TCF of -37ppm/°C.