Instability in hydrogenated amorphous silicon/amorphous silicon dioxide thin-film transistors: Evidence for a predominant effect of charge trapping into the gate insulator

Abstract

Negative-bias-stress and relaxation experiments on hydrogenated amorphous silicon/amorphous silicon dioxide (a-SiO₂) thin-film transistors show that the predominant instability mechanism is charge trapping in the gate insulator. The charge injection mechanism can be related to the presence of a defected region in the first 2–3 nm of the gate insulator. A possible cause of such a region could be the hydrogen-induced formation of defects in a-SiO₂, as evidenced by Auger electron spectroscopy.