New evidence was found for the H passivation and de-passivation of plasma charging-induced defects in oxides, and at oxide/Si interfaces. The plasma-charging defects which resulted from the processing of devices were shown to have various characteristics. Thus, the plasma-induced charging defects were latent (electrically inactive) directly after processing, and before post-metallization annealing. These defects continued to be latent after N2 and Ar annealing at temperatures ranging from 200 to 400C. These defects were also latent after standard post-metallization annealing in forming gas at 400C. The defects were electrically activated by room-temperature Fowler-Nordheim stress, or by annealing at temperatures below 400C in H-rich ambients. It was shown that H passivation and de-passivation was responsible for this behavior. Such passivation/de-passivation had previously been suggested to occur for defects at SiO2/Si interfaces. It was proposed here that it also described defect-H interactions in bulk gate oxides, for defects which were caused by plasma-charging.

O.O.Awadelkarim, S.J.Fonash, P.I.Mikulan, Y.D.Chan: Journal of Applied Physics, 1996, 79[1], 517-25