Hydrogen Gas Response of Pt-thin SiO₂-SiC Schottky Diode in the Presence of Oxygen

Abstract

A hydrogen gas sensor based on a Pt-thin SiO₂-SiC structure is fabricated and the behavior for a mixed hydrogen and oxygen gas at 300°C is studied and compared with previously published results for Si-based devices. The voltage response for a constant current is found to depend on the square root of hydrogen partial pressure, and decreases with increasing oxygen gas concentration. The coverage ratio of hydrogen atoms for adsorption sites exhibits a consistent correlation with normalized partial pressure P_H2^1/2/P_O2^1/4 for all mixtures of hydrogen and oxygen examined. The surface reaction mechanism by which H₂O is produced from adsorbed oxygen and hydrogen atoms is discussed based the results.