Improvement of thermal response in temperature controlled precise three-axis accelerometer with stabilized characteristics over a wide temperature range

Abstract

Improvement of the thermal response time of a temperature controlled three-axis accelerometer for high temperature environments with integrated microheaters and temperature sensors is presented. A detailed analysis of thermal response is carried out, and variation of thermal response with supply power is investigated using a simplified finite element method (FEM) model based on thermal response analysis. The thermal response analysis of the devices is investigated with the FEM program, ANSYS and infrared thermal measurement systems. The availability to application fields from the viewpoint of a short thermal response time is discussed. The time for a three-axis high temperature accelerometer to reach 300/spl deg/C, with integrated micro-heaters and temperature sensors to reduce thermal drift characteristics, was analyzed as the thermal response time of the device. The simulated thermal response time (time until SOI piezoresistors actually become 300/spl deg/C) of the three-axis high temperature accelerometer (using ANSYS) is about 600 ms, and the result measured by infrared temperature measurement systems is about 640 ms. Thermal measurement experimental results agreed well with these theoretical results. If electric power of about 260 mW is supplied to the integrated micro-heaters at around room temperature, the three-axis accelerometer reaches 300/spl deg/C within 90 ms.