Studies of NBTI in pMOSFETs with thermal and plasma nitrided SiON gate oxides by OFIT and FPM methods

NBTI in pMOSFETs with plasma (PNO) and thermal (TNO) nitrided SiON gate oxides are re-investigated using our newly developed on-the-fly interface trap (OFIT) and fast pulse I-V measurement (FPM) methods. The threshold voltage shift DeltaV_TH is quantitatively decomposed into interface trap and oxide charge components. It is found that the interface trap generation under stress follows the power law with the same power index n and its temperature dependence, indicating the same interface degradation mechanism for both PNO and TNO devices. The NBTI degradation in TNO devices is larger than those in PNO devices, particularly the larger component of oxide charge. The result is explained by the different N profile of TNO from that of PNO devices, as supported by the first principle calculation.