Oliver Blank

Analysis of NBTI Degradation- and Recovery-Behavior Based on Ultra Fast VT-Measurements

We present a new direct VT measurement technique with arbitrary choice of drain voltage and a mus delay (factor of 1000 improvement) after stress. As shown this technique enables a meaningful comparison of data to theory (e.g. DeltaVT measurable as response to stress times from 100mus over 10 decades in time and an analysis of recovery over 11 decades in time) which may lead to a better understanding of NBTI. A fast precursor due to bulk trapping was found to significantly influence degradation slopes for all times. Based on a physical model - standard reaction/diffusion model plus fast bulk trapping -with just 3 fit parameters experimental degradation can be well modelled and degradation slopes <frac14 as well as > frac14 (both reported in literature) can be explained. A lifetime extrapolation based on this physical model is superior to the common straight line fit. There is no satisfying agreement of recovery data with reaction/diffusion theory. Further experimental and theoretical work is going to be needed

A Comparison of Very Fast to Very Slow Components in Degradation and Recovery Due to NBTI and Bulk Hole Trapping to Existing Physical Models

A new measuring technique with a 1mus measuring delay and a direct VT determination has been employed. The response to stress times as short as 100 mus to 105 has been studied as well as recovery over 12 decades in time. These experimental data allow a meaningful comparison to theory. Degradation data cut be precisely fitted to a simple physical model with 3 parameters thus enabling a reliable lifetime prediction from stress times below 104s.

Robustness of MOSFET devices under hard commutation ofthe body diode

This paper presents a study of the behavior of power MOSFET devices under hard commutation of the body diode as well as improvements of that behavior shown by latest technology developments based on detailed simulations of the device. Hard commutation of the body diode can represent a challenging mode of operation in regards to the ruggedness of power MOSFET devices. Also, the behavior of the body diode under hard commutation and its corresponding effects on the application are analyzed.