An Improved Physical Model Considering Mirco-Nano Scale Effects for Numerical Simulation of Pirani Vacuum Gauges

An improved physical model was proposed for accurate electrothermal modeling Pirani vacuum gauges (PVG) by accounting for the micro-nano scale effects of heat transfer in sensitive elements and the non-negligible corner heat dissipation from multiple heat sinks. This model is verified by published experimental data and can reveal the influences of geometrical, physical and process parameters, such as device dimensional size, temperature and doping concentrations, on the micro-nano scale heat transfer process, which is a great consideration for microelectromechanical systems (MEMS) PVG designing. Although the model is initially envisaged for MEMS PVG, it could be straightforwardly adopted for the thermal sensors with silicon heaters. Finally, the characteristics of PVG were comprehensively investigated based on the presented model validated by the experimental data. The results show that expanding the area ratio of heat sinks to heater and the thermal resistance ratio of heater to gas is an effective design idea to optimise the maximum sensitivity and central pressure of device.