Thermal Conductivity Gas Sensors for High-Temperature Applications

Abstract

This paper describes a fast and flexible microfabrication method for thermal conductivity gas sensors useful in high-temperature applications. The key parts of the sensor, the microheater and the package, were fabricated from glass-coated platinum wire and the combination of laser micromilling (ablation) of already-sintered monolithic ceramic materials and thick-film screen-printing technologies. The final thermal conductivity gas sensor was fabricated in the form of a complete MEMS device in a metal ceramic package, which could be used as a compact miniaturized surface-mounted device for soldering to standard PCB. Functional test results of the manufactured sensor are presented, demonstrating their full suitability for gas sensing applications and indicating that the obtained parameters are at a level comparable to those of standard industrially produced sensors. The results of the design and optimization principles of applied methods are discussed with regard to possible wider applications in thermal gas sensor prototyping in the future. The advantage of the developed sensors is their ability to operate in air environments under high temperatures of 900 °C and above. The sensor element material and package metallization were insensitive to oxidation compared with classical sensor-solution-based metal–glass packages and silicone MEMS membranes, which exhibit mechanical stress at temperatures above 700 °C.

Modeling and Design Parameter Optimization to Improve the Sensitivity of a Bimorph Polysilicon-Based MEMS Sensor for Helium Detection

“…sensors have been found in many applications, including coal mines, natural gas monitoring (for methane sensing), and light gases such as hydrogen [7].…”

“…Thermal conductivity-based gas sensors have advantages, including eliminating catalysts and adsorbents [ 5 , 6 ]. Moreover, thermal conductivity gas sensors have been found in many applications, including coal mines, natural gas monitoring (for methane sensing), and light gases such as hydrogen [ 7 ].…”

Characterization of Sand and Dust Pollution Degradation Based on Sensitive Structure of Microelectromechanical System Flow Sensor

“…In order to investigate the specific effects of dust particles on the failure modes of MEMS devices [9] and to assess their reliability, we propose a dust particle contamination experiment. This experiment aims to explore the effect of electrostatic forces [10] generated by friction between dust particles on the electrical characteristics of MEMS sensors [11], and to provide a guiding principle for investigating the fundamentals of MEMS failure. In previous studies, Yuan Changrong [12] specifically analyzed the extent to which the presence or absence of contaminants affects the flow velocity on the surface of the sensor chip through fluent fluid simulation software, and Wei Yujin [13] conducted modeling and simulation experiments on contamination in the sensitive region of a MEMS flowmeter using COMSOL software 6.0.…”