On-wafer I/V measurement setup for the characterization of low-frequency dispersion in electron devices

Large-signal dynamic modelling of 111-V FETs cannot he simply based on DC i/v characteristics, when accurate performance prediction is needed. In fact, dispersive phenomena due to self-heating and/or traps (surface state densities and deep level traps) must be taken into account since they cause important deviations in the low-frequency dynamic drain current. Thus, static drain current characteristics should he replaced with a suitable model which also accounts for low-frequency dispersive effects. The research community has proposed different modelling approaches and quite often a characterization by means of pulsed i/v measurement systems has been suggested as the more appropriate for the identification of low-frequency drain current models. In the paper, a new large-signal measurement setup is presented which is based on simple low-frequency sinusoidal excitations and it is easily reproducible with conventional general-purpose lab instrumentation. Moreover, the proposed setup is adopted in the paper to extract a backgating-like model for dispersive phenomena