We describe the fabrication processes and the characterizations of a MEMS (Micro-electromechanical systems) based hydrogen gas sensor. The gas sensor is made by MEMS based on a semiconductor fabrication method except for the ceramic bulk. The heating electrode and sensing electrode were formed being apart from the substrate by using MEMS and SnO2 ceramic bulk as a gas sensitive material was formed extending over the heating and sensing electrode. The SnO2 gas sensor with the micro-hotplate showed good response to the H2 gas at 50-20,000 ppm and high selectivity as compared to other gases as CO, H2S, and CH4. The value obtained of the TCR is 1.61 × 10-3 K-1. The TCR of the micro hotplate is lower than the TCR of bulk Pt as the thickness of the micro hotplate is only 2 μm.
- Temperature coefficient of resistance
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering