A three-axis accelerometer for high temperatures with low temperature dependence using a constant temperature control of SOI piezoresistors

In this paper, a three-axis accelerometer for high temperatures using constant temperature control of SOI piezoresistors is proposed for reduction of temperature drift. The accelerometer has surrounding mass structure, and piezoresistors for four wheatstone bridges to detect three-axis acceleration. A temperature sensor using the whole resistance of four wheatstone bridges and micro-heaters are integrated on the beam structures. The structure of accelerometer was optimized with finite element method simulation program, ANSYS. Temperature dependence of the fabricated three-axis accelerometer on variation of atmosphere temperature (room temperature to 300/spl deg/C) is much reduced by keeping the temperature of piezoresistors at 300/spl deg/C. Temperature Coefficient of Sensitivity (TCS) is much reduced to 72% of the original TCS.