2.1 Measurement-Stress-Measurement
The probably most widespread measurement technique when investigating BTI
issues is the so-called Measurement-Stress-Measurement (MSM) method. In
the most simple way the transistor is first characterized through static
-measurements to obtain a reference of the threshold voltage. (Other
ways to extract the onset of the threshold region are listed in [16].) Then 
is
set to 
for some specified time, referred to as the stress time 
. After the
end of stress the device is once again characterized and the amount of
degradation is estimated by the difference with respect to the initial
characteristic. The MSM-method can be performed by either monitoring 
and a subsequent conversion into a 
-shift or by directly monitoring
.
at 
