Low temperature dependence three-axis accelerometer for high temperature environments with temperature control of SOI piezoresistors

Abstract In this paper, a three-axis accelerometer for high temperatures using constant temperature control of silicon on insulator (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 (FEM) simulation program, ANSYS. The accelerometer was fabricated with SOI wafers by bulk-micromachining. Temperature dependence of the fabricated three-axis accelerometer on variation of atmospheric temperature (from room temperature to 300 °C) is much reduced by keeping the temperature of piezoresistors at 300 °C. Temperature coefficient of sensitivity (TCS) is much reduced to 72% of the original TCS.