Application of deep reactive ion etching for silicon angular rate sensor

A new silicon resonant angular rate sensor by deep reactive ion etching was developed. The sensor consists of a glass-silicon-glass structure. To have a sensor of high Q factor, a one-side suspended tuning fork structure was adopted. The silicon resonator structure which has high aspect ratio was machined by reactive ion etching. The etching gas of the RIE was SR₆ and etching rate was 0.8 μm/min. The resonator is driven electromagnetically and the torsional vibration caused by the Coriolis force is detected capacitively. The test device showed a sensitivity of 6 fFsec./deg. and had an output to the angular rate in a range from -360 deg./sec to 240 deg/sec.