Characterization of a novel microhotplate for application in a silicon-based nanofilm gas sensor

The micro-hotplate is the core component of the silicon-based nano-film gas sensor and directly affects the overall performance. This paper first analyzes the heat dissipation of the micro-hotplate and establishes a heat transfer calculation model. Multiphysics coupling is used to optimize the arrangement of the heating and test electrodes to obtain the best design of the micro-hotplate. Next, silicon-based micro-electro-mechanical system (MEMS) performs micro-hotplate processing and electrical connections according to the parameters optimized by the finite element. Lastly, the temperature coefficient of resistance measurement and infrared microscopic imaging were used to complete the characterization of the hotplate and the verification of the theoretical simulation was completed. The size of the micro-hotplate unit is 500 μm × 500 μm, and the area of the heating film area is 160 μm × 160 μm. The micro-hotplate designed in this paper has low power consumption and may be operated up to 357.5 °C with a power of 28.6 mw. Below the working temperature of 357.5 °C, the resistance of the micro-hotplate has an excellent linear relationship with temperature without warping or fracture. The micro-hotplate is small in size and may allow large-scale sensor array integration.