Hydrogen-induced change in the electrical properties of metal-insulator-semiconductor Pt-GaN diodes

摘要

Exposure of Pt-SiO_2-GaN diodes to hydrogen at room temperature is found to change the conduction mechanisms from Fowler-Nordheim tunneling to Pool-Frenkel emission. The capacitance-voltage (C-V) curve for Pt-SiO_2-GaN diodes in hydrogen significantly shifts toward negative bias values as compared with that in nitrogen. In sharp contrast, Pt-Si_xN_y-GaN diodes exhibit Pool-Frenkel emission in nitrogen and do not show any change in the conduction mechanism upon exposure to hydrogen. The C-V curve for Pt-Si_xN_y-GaN diodes also does not show any shifts upon the exposure to hydrogen. These results suggest that the work function change in the Schottky metal is not responsible mechanism for the hydrogen sensitivity. The interface between the metal and the semiconductor plays a critical role in the interaction of hydrogen with semiconductor devices, including diodes and field-effect transistors (FETs).