MEMS Pirani Sensor for Pressure Measurements in the Fine- and High-Vacuum Range

M. Grau[1], F. V├Âlklein[1], A. Meier[1], C. Kunz[1], P. Woias[2]
[1]RheinMain University of Applied Sciences, Institute for Microtechnologies, R├╝sselsheim, Germany
[2]University of Freiburg, Department of Microsystems Engineering, Freiburg, Germany
Published in 2014

A high performance MEMS Pirani sensor (VAC_03) was designed and optimized based on analytics. Due to the fact that this MEMS Pirani sensor is a 3D-Object, the calculation of the thermal radiation by analytics is limited. As the radiation behavior in the system is, beside the solid thermal conductance, responsible for the low-pressure detection limit of such vacuum gauges, we switched to a FEM-Software for analyzing the actual 3D-geometry. This way all view factors of the interacting surfaces can be precisely calculated. Gaseous heat flux calculation is based on analytical equations. We use the model for further geometric optimization by systematically sweeping crucial parameters, so that we can approximate the gain in sensitivity related to the technological effort.