Accurate Modeling of Electron Device I/V Characteristics Through a Simplified Large-Signal Measurement Setup

Low-frequency dispersive phenomena due to self-heating and/or traps (that is, surface-state densities and deep-level traps) cause important dynamic deviations in the I/V characteristics of III-V devices and they must be taken into account when an accurate large-signal dynamic model is needed. To this end, different low-frequency dispersive I/V models have been proposed by the research community and, quite often, a characterization based on pulsed I/V measurement systems has been suggested as the most appropriate for the identification of model parameters. Unfortunately, besides requiring special-purpose setups, pulsed characterization may suffer from some drawbacks, as discussed in this article. As an alternative, a simple large-signal measurement setup is presented here, which is based on low-frequency sinusoidal excitations and can be easily implemented by means of conventional general-purpose laboratory instrumentation. The proposed setup is successfully adopted in this article to identify the dispersive I/V characteristics of a GaAs PHEMT large-signal model providing excellent prediction of intermodulation distortion at Ka-band frequencies.