Palladium Based Mems Hydrogen Sensors

Abstract

The paper describes a novel approach of a new sensor based on a micro-electromechanical system (MEMS). These sensors utilise the volume change of Pd due to hydrogenation, thus they switch mechanically. Pd and Pd-alloy ultrathin films have been deposited on the membrane of Si-MEMS chips by magnetron sputtering. Our investigations revealed a reversible switching of MEMS-Pd-sensors without any drift. The sensor shows a fast response for hydrogen concentrations at and below the lower explosion limits up to 100%vol. hydrogen. Besides this, Pd based sensors show low cross sensitivities and particularly no cross sensitivity to methane (CH 4 ) since the switching mechanism is a physical one.