Demonstration of a micro-hotplate chip with a good temperature uniformity

The gas sensor based on Micro-electromechanical system (MEMS) technology has the advantages of high sensitivity, small size, good batch uniformity and low power consumption. It has become an important development direction of the next-generation semiconductor gas sensor. This paper focuses on the design of the micro-hotplate chip for MEMS gas sensors. A type of micro-hotplate chip design with an isothermal hot area (±15 K) accounting for 90% is demonstrated through both the thermal theory analysis and the finite element simulation of the physical field, effectively resolving the issue of broad area uniform heating in the micro-sized chip in MEMS gas sensor designs. The infrared thermal image test results show the temperature of four points from edge to center of heating area are 295.5 °C, 287.5 °C, 289 °C, 294.8 °C respectively, which indicates the heat uniformity of micro-hotplate. Due to the limitation of a low temperature film deposition process, the maximum stress of the micro-hotplate films is about 1500 MPa, and at 375 °C operating temperature, the power consumption per area is only 4.5×10-4 mW/μm2.