Simulation and performance study of low-power magnetron sputtered ZnO methane sensor

With the development of the industry of semiconductor integrated circuits, microelectromechanical system (MEMS) products have made rapid progress. The development of MEMS and the combination of sensor technology have yielded compact sensors with increased functions and intelligence levels. MEMS-based microhotplate (MHP)-type metal oxide methane sensors have the advantages of low power consumption and fast response and have been widely used in methane detection applications. In particular, ZnO methane-sensitive materials have attracted significant attention due to their high sensitivity, small poisoning effect, and low operating temperature. Notably, the response performance of sensors prepared from these sensitive materials is still significantly affected by the heating temperature and thermal distribution of the MEMS-based MHP. The purpose of our experiment is to optimize the heat generation of the heating electrodes of MHP, optimize the thermal distribution of MHP, and further reduce the power consumption of MHP sensors. The heating electrodes of MHP are made of platinum materials that have high thermal conductivity and stable performance. In this study, we use the Multiphysics module in the finite element analysis software COMSOL to simulate and analyze the temperature in the physical field for the two structures of serpentine platinum heating electrodes of MHP. By comparison, the structure of the heating electrodes affects the temperature distribution under the same working conditions. The structure with a larger width in the middle of the heating plate electrode and gradually narrowing to both sides generates more heat than that with the same width. When the heating plate reaches 300 ℃, it needs about 75 mW of power. Next, ZnO thin film methane sensors were constructed by sputtering ZnO methane-sensitive materials on the interdigital electrode of a commercial MHP, and the response of the gas sensor was tested using the HIS9010 of Hefei Micro-Nano Company. The static measurement method was used to inject methane gas into a 1-L gas chamber. In order to verify the superior response of our sensor, it has been compared that performance of commercial methane sensors and ZnO methane sensors made by. The response linearity in the interval is relatively good, and the response value for 10000×10⁻⁶ methane reaches 30. The response of our fabricated sensor is higher than those of existing domestic and foreign commercial methane sensors, showing significant potential in related applications.