A geometry dependent predictive FEM model of a high temperature closed membrane SOI CMOS MEMS thermal conductivity sensor

This paper presents an experimentally verified geometry dependent predictive FEM model of a high temperature closed membrane thermal conductivity sensor. The sensor was developed using SOI CMOS MEMS technology. The FEM model presents a systematic approach to design thermal conductivity sensors by understanding heat transfer mechanisms between the sensor and the analyte environment. It also discusses how response time and sensor sensitivity are influenced by geometry of the sensor. The sensor was fabricated at a commercial foundry using a 1 μm process and measures only 1×1 mm². The model establishes that a tradeoff is required between power consumption, response time and sensitivity based on the end user application.