Electrode Design and Device Optimization of MEMS Micro-hot Plate Based on Gas-sensitive Performance

Gas sensors based on MEMS are facing challenges such as the limited variety of micro-hot (MHP) plate structures and the low heating efficiency of MHP. This work employed COMSOL's multiphysics coupling capabilities combined with experimental validation to design and simulate a MHP structure characterized by high heat transfer efficiency, low stress, and structural stability. Based on the diverse thermal and mechanical simulation outcomes, an in-depth investigation into the influence mechanisms of MHP structural morphology, geometry, electrode patterns, and other conditions on the temperature field and thermal stress concentration within MEMS devices was conducted. This work designed and obtained the optimal device structure. At the same time, verification is conducted through experimental methods. Based on simulation results, two MHP devices were developed and manufactured using zinc oxide as the gas-sensitive material to validate their performance. Using MEMS micro-electro-mechanical systems, hydrogen gas at 500 ppm was detected at different temperatures, while their thermal and mechanical properties were simultaneously investigated. The MHP structure designed in this paper achieves the optimal operating temperature of 265°C at an extremely small voltage (0.2V), while the overall structure maintains a small deformation (<2μm). The response values of the two devices to hydrogen gas reached 6.55 and 5.47, respectively, far exceeding those of conventional planar devices. This work shows a new design method of mems chip, which can measure the concentration of hydrogen more accurately and has accurate gas sensitivity measurement ability. It plays an important role in the field of hydrogen energy safety.