Evaluation of Advanced MOSFET Threshold Voltage Drift Measurement Techniques

The experimental characterization of the threshold voltage shift in metal-oxide-semiconductor field-effect transistors due to degradation mechanisms like bias temperature instability and hot-carrier degradation requires a careful consideration of various pitfalls. One of them concerns the comparability between the threshold voltage shifts obtained by different extraction methods. The focus of this paper is set on the comparison of two extraction methods used at recovery conditions, the constant current and the constant voltage method. Although considered equivalent, a thorough experimental analysis shows that the equivalence of both methods is limited by a low device parameter change during degradation, a measurement in the sub-threshold region, and the consideration of device-to-device variability.