An improved methodology for monitoring NBTI induced threshold voltage shift of scaled p-MOSFETS

Conventional fast switching measurement method for NBTI characterization, which relates linear drain current degradation DeltaI
_d
to threshold voltage shift |DeltaV
_t
| based on the first-order expression |DeltaV
_t
| = intpartI
_d
/g
_m
, is shown to severely overestimate |DeltaV
_t
|. By taking into account the effect of source/drain series resistance and vertical-field induced mobility reduction, results obtained using an improved ultra-fast switching method are shown to be consistent with those obtained from alternative ultra-fast V
_t
and gate-voltage sweep methods.