Title :
Fabrication, characterization, and analysis of a DRIE CMOS-MEMS gyroscope
Author :
Xie, Huikai ; Fedder, Gary K.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Florida, Gainesville, FL, USA
Abstract :
A gyroscope with a measured noise floor of 0.02°/s/Hz12/ at 5 Hz is fabricated by post-CMOS micromachining that uses interconnect metal layers to mask the structural etch steps. The 1 × 1 mm lateral-axis angular rate sensor employs in-plane vibration and out-of-plane Coriolis acceleration detection with on-chip CMOS circuitry. The resultant device incorporates a combination of 1.8-μm-thick thin-film structures for springs with out-of-plane compliance and 60-μm-thick bulk silicon structures defined by deep reactive-ion etching for the proof mass and springs with out-of-plane stiffness. The microstructure is flat and avoids excessive curling, which exists in prior thin-film CMOS-microelectromechanical systems gyroscopes. Complete etch removal of selective silicon regions provides electrical isolation of bulk silicon to obtain individually controllable comb fingers. Direct motion coupling is observed and analyzed.
Keywords :
CMOS integrated circuits; Coriolis force; gyroscopes; micromachining; microsensors; sputter etching; 5 Hz; CMOS-MEMS gyroscope; Coriolis acceleration; Si; angular rate sensor; comb finger; deep reactive ion etching; electrical isolation; inertial sensor; micromachining; noise floor; proof mass; single crystal silicon microstructure; spring; thin film system; vibration; Acceleration; Etching; Fabrication; Gyroscopes; Integrated circuit interconnections; Micromachining; Noise measurement; Silicon; Springs; Thin film circuits;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2003.817901