MEMS-based resistive hydrogen sensor with high performance using a palladium-gold alloy thin film

Hydrogen sensors have been widely used in several fields for monitoring the concentration of hydrogen and for its alarming leakage. In this study, a microelectromechanical systems (MEMS)-based resistive hydrogen sensor using a palladium-gold (Pd-Au) alloy thin film was developed, which has the advantages of low power consumption, mass production, and high performance. A sensitive alloy film was prepared by DC magnetron sputtering deposition and annealed at various temperatures. It was integrated on a patterned silicon substrate with heating and temperature detection resistances and fabricated by MEMS processes. This film exhibited the best response performance to hydrogen at annealing and working temperatures of 200 and 60 °C, respectively. The sensor exhibited a good response to hydrogen from 5 ppm to 3%. The response attained a value of 3.3%, and the response and recovery times were 22 and 160 s, respectively, for a hydrogen concentration of 3%. The sensor also indicated good repeatability, long-term stability, and high selectivity for hydrogen over other gases (sulfur dioxide, ethanol, methane, ammonia, carbon monoxide, nitrogen dioxide, and formaldehyde). Thus, it has good potential for the detection of hydrogen leakage in new energy vehicles.