Comparison of hot-carrier degradation in n- and p-MOSFETs with various nitride-oxide gate films

The electrical characteristics of MOSFETs with three types of gate insulator, pure gate oxide, rapid thermal nitrided oxide, and stacked nitride oxide, were compared. While the stacked nitride oxide sample has been regarded as a highly reliable insulator for TDDB, it has lower hot carrier reliability in both threshold voltage shift and interface state generation. RTP samples have very small interface state generation during stress application, while the threshold voltage shift is comparable (nMOS case) to or even worse (pMOS case) than that for the pure oxide gate sample. The relationship between hot carrier degradation and substrate/gate current during stress is discussed.