A Novel Miniature and Selective CMOS Gas Sensor for Gas Mixture Analysis-Part 4: The Effect of Humidity.

Area of Science:

• Materials Science and Engineering
• Chemical Sensing Technologies
• Microelectromechanical Systems (MEMS)

Background:

• Miniature combustion-type gas sensors (GMOS) utilize a novel thermal sensor (TMOS), a micromachined CMOS-SOI transistor with a catalytic plate.
• GMOS sensors measure temperature changes from gas combustion exothermic reactions, controlled by ignition temperature and hotplate temperature.
• The sensor relates electrical parameters to thermal parameters, using Joule heating and monitoring TMOS voltage changes relative to a blind sensor.

Purpose of the Study:

• To investigate the effect of humidity on the performance of GMOS and pellistor gas sensors.
• To address challenges in simulating sensor performance under humidity, including defining operating temperature, measuring temperature dynamics, and modeling sensing response.
• To validate the operational capability of the GMOS sensor in high humidity conditions.

Main Methods:

• Utilized advanced simulation software incorporating computational fluid dynamics (CFD) for complex 3D analysis of packaged GMOS.
• Conducted experimental studies to assess sensor performance under varying humidity levels.
• Employed a blind sensor as a reference for both temperature and voltage measurements.

Main Results:

• Simulation and experimental data confirm that the GMOS sensor maintains operational capability in the presence of high humidity.
• The study provides insights into the challenges and methodologies for simulating gas sensor performance with humidity as a factor.
• Established a correlation between operating temperature, sensing response, and humidity levels.

Conclusions:

• The developed GMOS sensor demonstrates robust performance, functioning effectively even in high humidity environments.
• This research significantly enhances the understanding of humidity's impact on combustion-type gas sensors.
• The findings support the deployment of GMOS sensors in real-world applications where humidity is a prevalent environmental parameter.