Why is oxide-trap charge-pumping (OTCP) method appropriate for extracting the radiation-induced traps in mosfet?

Oxide-trap charge-pumping (OTCP) method is used to estimate radiation-induced oxide-, interface-, and border-traps in complementary N- and P-MOS transistors. We conduct a critical comparison between OTCP and classical methods like subthreshold slope (STS), mid gap (MG), dual-transistor charge-pumping (DTCP), and dual-transistor border-trap (DTBT). On the one hand, OTCP offers more accurate densities of radiation-induced interface-traps (DeltaN
_it
) and border-traps (DeltaN
_bt
), while STS and MG overestimate DeltaN
_it
because both interface- and border-trap are sensed like interface-traps. On the other hand, OTCP estimates DeltaN
_it
, DeltaN
_bt
, and radiation-induced oxide-trapped positive charge (DeltaN
_ot
) for N- and P-MOS separately, whereas DTCP and DTBT give average densities for both devices.