A single-crystal silicon symmetrical and decoupled gyroscope on insulating substrate

This paper presents a single-crystal silicon symmetrical and decoupled (SYMDEC) gyroscope implemented using dissolved wafer process on an insulating substrate. The symmetric structure allows matched resonant frequencies for the drive and sense vibration modes for high rate sensitivity and low temperature-dependent drift, while the decoupled drive and sense modes prevents unstable operation due to mechanical coupling, achieving a low bias drift. The 12-15 /spl mu/m-thick single-crystal silicon structural layer with an aspect ratio about 10 using DRIE patterning provides a high sense capacitance of 130fF, while the insulating substrate provides a low parasitic capacitance of only 20fF. Drive and sense mode resonance frequencies of the gyroscope are measured to be 39,010 Hz and 38,570 Hz, respectively. Measurement results reveal that the gyroscope provides a rate sensitivity of 0.01 deg/sec in 50 Hz bandwidth at vacuum.