The Sensing Mechanism and the Response Simulation of the MIS Hydrogen Sensor

The pure Pd and Pd alloy gated metal-insulator-semiconductor (MIS) hydrogen sensors have been studied. The chemical state of palladium in Pd and Pd alloy gated devices is similar and Pd alloy devices show a wide dynamic range. According to the hydrogen induced capacitance-voltage ( CV) shift and the response from a refreshed sensor, a new sensing mechanism is proposed that the hydrogen response is due to the protons on the metal/insulator interface and some of the protons take a long time to be desorbed from the interface. Based on this mechanism, a one-dimensional model is constructed with the consideration of the series resistance and fixed positive charges to simulate the CV/GV curves and hydrogen response from the Pd-Cr gated device.