A Tunable Palladium-Based Capacitive MEMS Hydrogen Sensor Performing High Dynamics, High Selectivity and Ultra-Low Power Sensing
(2014) Procedia Engineering — Vol. 87, p. 268-271 (2014)
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- Abstract
- We developed an ultra-low power MEMS hydrogen (H2) sensor performing high dynamics together with high sensitivity up to the Lower Explosive Limit (LEL), i.e. 4% vol. H2 in dry air. The architecture consists of Al clamped-clamped beams (700 nm- thick, 800 μm-total width, 140 or 240 μm-length) with both ends made of a Pd/Al bimorph (200/700 nm-thick) on a quarter of its length, acting as actuators, released above a split-bottom electrode. The initial stress defines the initial deflection of the structure while the Pd-hydriding induces compressive stress variation in the Pd actuator layer and therefore the membrane deflection. A capacitive transduction is used to continuously measure the gap variation due to the H2 absorption and hydriding kinetic. Results show a fast response time of less than 5 s for an effective concentration of about 0.2% vol. H2 in dry air or N2 mixture, with no cross sensitivity.
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Citations
Walewyns, T., Spirito, D., & Francis, L. (2014). A Tunable Palladium-Based Capacitive MEMS Hydrogen Sensor Performing High Dynamics, High Selectivity and Ultra-Low Power Sensing. Procedia Engineering, 87, 268-271. https://doi.org/10.1016/j.proeng.2014.11.659 (Original work published 2014)