According to one embodiment, a method for isolating degradation mechanisms
in transistors includes providing a ring oscillator having a plurality of delay
elements. Each delay element operates as a delay element through the use of one
or more transistors of only a first type and no transistors of the opposite type.
The method further includes operating the ring oscillator and measuring the frequency
resulting from the ring oscillator over time. The magnitude of an isolated degradation
mechanism is determined based on a comparison of the measured frequency and an
expected frequency for the ring oscillator absent degradation.