Creation of near-interface defects in hydrogenated amorphous silicon-silicon nitride heterojunctions: The role of hydrogen

Charge trapping was measured at the hydrogenated amorphous silicon-silicon nitride interface. Hole accumulation primarily causes holes to tunnel deep into bulk states of the nitride while electron accumulation primarily generates interface states. The time dependence of the creation process is consistent with phenomena such as other metastable effects and hydrogen diffusion. In fact, the creation process can be fit over seven decades of time by a stretched exponential with parameters which agree well with these other phenomena. The results support the idea that hydrogen diffusion underlies many of the metastable phenomena in hydrogenated amorphous silicon.