With the help of the pulsed measurement techniques presented in this chapter,
the FPM and the OFIT technique, it was tried to reveal the recovery accounting
for BTI. The FPM technique provides a sophisticated way to monitor the
degradation of a MOSFET when the data is extracted consistently. Nevertheless,
it suffers from a serious shortcoming: It is not suited for PBTI, since the
determination of 
requires to reach deep inversion which should be avoided
as far as possible in order to avoid a superposition of NBTI and PBTI. This
renders a precise and equivalent comparison of NBTI and PBTI impossible. In
spite of that the previously observed positive 
-shift during FPM which
was explained by electron tunneling could not be reproduced. Quite the
contrary, solely negative 
-shift was observed for both NBTI and
PBTI.
The second proposed pulse technique performs constant base-level charge
pumping measurements to access the dynamics of interface states. Thereby it was
found that the charge pumping current 
is not constant in the inversion
regime, but increases due to slow oxide traps. As a consequence, the data
gathered during stress and recovery phases for the OFIT measurement technique
is fundamentally different and must not be directly compared, as for example
done in [101]. When also oxide traps with a thermally activated barrier are
considered in addition to interface states, the OFIT results do not show fast
initial degradation or fast recovery of interface states after one second anymore.
The real short-term behavior will be elaborately examined in Chapter 6 and
7.