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In this paper, we describe a methodology for temperature stabilization of CMOS micromachined sensors. Temperature stabilization of a z-axis accelerometer, fabricated in a 0.5µm Agilent CMOS process is demonstrated. The accelerometer motion is sensed by a vertical comb drive designed by controlling the rotor and stator curvature. The polysilicon layer of the CMOS process has been utilized for heating the device structure to a constant temperature, that is higher than the maximum ambient operating temperature. The capacitance detection circuits have temperature independent gain. The D.C. bias stability of the accelerometer improved from 1.9 G/ºC, to 42 mG/ºC, and the sensitivity stability improved from 60% to 18% over a temperature of 70ºC after temperature control.
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