Thermal Characteristics in Motion Sensor for High Temperature environments

In this paper, improvement of thermal response time of a temperature controlled motion sensor for high temperature environments with integrated micro-heaters and temperature sensors is presented. More detailed analysis of thermal response is carried out, and variation of thermal response with supply power energy is investigated using simplified finite element method (FEM) model based on thermal response analysis. Thermal response analysis of the devices is investigated with FEM program, ANSYS and infrared thermal measurement systems. And availability to application fields from a viewpoint about short thermal response time is discussed. In this paper, the time of motion sensor for high temperatures becoming 300degC by integrated micro-heaters and temperature sensors to reduce thermal drift characteristics was analyzed as a thermal response time of this device. The simulated thermal response time (time until SOI piezoresistors actually becomes 300degC) of motion sensor for high temperatures with ANSYS is about 600 ms, and measured result with infrared temperature measurement systems is about 640 ms. Experimental results using infrared thermal measurement systems agreed well with these theoretical results. As the results, if the electric power of about 260 mW is supplied to the integrated micro-heaters being around room temperature, the motion sensor reached at 300degC within 90 ms.