Calibration of an integrated hydrogen gas-sensing system

An accurate and flexible calibration model has been developed for a single-chip integrated hydrogen-sensing system. The model continuously provides the hydrogen concentration from measurements of the palladium-nickel film resistor, which serves as the active gas-sensing structure, and an on-chip thermometer. Calibration parameters are easily determined from simple measurements that utilize temperature control provided by on-chip heaters. The model is shown to yield accurate results in practical environments, i.e., where time-dependent temperatures and hydrogen concentrations coexist. The model enables the implementation of small practical hydrogen-sensing systems based on an integrated hydrogen-sensing chip.