Tungsten is consider to be the most suitable material for the CMOS-MEMS vacuum gauges, including Pirani vacuum gauge and ionization vacuum gauge, due to its high temperature coefficient, resistant to the electromigration failure, high melting point, thermionic emission and CMOS compatible. This paper introduces the tungsten application in CMOS-MEMS Pirani and ionization vacuum gauges.In our design of the Pirani gauge, tungsten is adopted as the heater in the form of serpentine resistor instead of via plug.the measurement results show that the gauge has a response to the gas pressure form 100000Pa to 0.1Pa.The ionization vacuum gauge is introduced to measure high vacuum, below 0.1Pa.In our design with CMOS process, the tungsten microbridge is employed as the cathode, grid and anode. The ionization vacuum gauge is designed to response from 1Pa to 0.001Pa. With the adoption of tungsten, it is possible to fabricate the Pirani gauge and the ionization gauge in a chip. It will be more convenient for the rough, medium and high vacuum measurement. What is more, due to the good thermal performance, the tungsten can be applied to other CMOS-MEMS thermal-based sensors to replace the Polysilicon or other thermal resistor materials.
Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2013: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational (Volume 2)
Published: May 12, 2013
Pages: 146 - 149
Industry sector: Sensors, MEMS, Electronics
Topics: MEMS & NEMS Devices, Modeling & Applications