Empirical modeling of low-frequency dispersive effects due to traps and thermal phenomena in III-V FET´s

The modeling of low-frequency dispersive effects due to surface state densities, deep level traps and thermal phenomena plays an important role in the large-signal performance prediction of III-V FET´s. This paper describes an empirical modeling approach to accurately predict deviations between static and dynamic drain current characteristics caused by dispersive effects in III-V devices operating at microwave frequencies. It is based on reasonable assumptions and can easily be embedded in nonlinear FET models to be used in Harmonic-Balance tools for circuit analysis and design. Experimental and simulated results, for HEMT´s and GaAs MESFET´s of different manufacturers, that confirm the validity of the new approach, are presented and discussed together with the characterization procedures required