CMOS MEMS Fabrication Technologies and Devices

This paper reviews CMOS (complementary metal-oxide-semiconductor) MEMS (micro-electro-mechanical systems) fabrication technologies and enabled micro devices of various sensors and actuators. The technologies are classified based on the sequence of the fabrication of CMOS circuitry and MEMS elements, while SOI (silicon-on-insulator) CMOS MEMS are introduced separately. Introduction of associated devices follows the description of the respective CMOS MEMS technologies. Due to the vast array of CMOS MEMS devices, this review focuses only on the most typical MEMS sensors and actuators including pressure sensors, inertial sensors, frequency reference devices and actuators utilizing different physics effects and the fabrication processes introduced. Moreover, the incorporation of MEMS and CMOS is limited to monolithic integration, meaning wafer-bonding-based stacking and other integration approaches, despite their advantages, are excluded from the discussion. Both competitive industrial products and state-of-the-art research results on CMOS MEMS are covered.