Charge trapping during constant current stress in Hf-doped Ta2O5 films sputtered on nitrided Si

Applying a trapping kinetics model, two trapping sites with characteristic trapping times τ1 = 3.2 s and τ2 = 49 s were determined and attributed to pre-existing defects in the bulk Hf:Ta2O5 layer and not in the interfacial SiOxNy layer. It was found that both τ1 and τ2 do not depend on Js, which may be explained by the presence of a mechanism of charging the active sites through field activated emission of charge from them.