Influence of transferred-electron effect on drain-current characteristics of AlGaN/GaN heterostructure field-effect transistors

An analytical model, with incorporation of transferred-electron effect, for drain-current characteristics of AlGaN/GaN heterostructure field-effect transistors (HFETs) is presented. The transferred-electron effect is often neglected in modeling the drain-current of III-V HFETs. The broad steady-state electron drift-velocity overshoot of GaN in comparison to other direct semiconductors such as GaAs and InP, in addition to the larger difference between the peak and saturation drift-velocity, and the wider band gap of this semiconductor suggest the importance of the incorporation of transferred-electron effect (i.e., steady-state drift-velocity overshoot) in modeling the drain-current of these devices. Simulation results are compared with the results of the adoption of a saturating drift transport model, which has been recently used in modeling the drain-current of these devices. Comparisons between the two models demonstrate the importance of the consideration of transferred-electron effect, especially as the Ohmic contact quality is improved. (C) 2011 American Institute of Physics. [doi:10.1063/1.3533941]