Influence of surface-trap dynamics on impact-ionization and kink phenomena in AlGaAs/GaAs HFETs

The kink effect is a detrimental phenomenon for the performance of III-V compound semiconductor FETs, resulting in output-conductance increase, transconductance compression, and dispersion between DC and RF characteristics. Although several papers have been dedicated to it, the physical origin of this effect is still a debated issue [1-4]. The aim of this work is to provide insight about the physical origin and the dynamic behavior of the kink in AlGaAs/GaAs HFETs. To this purpose, DC and pulsed measurements on both virgin and hot-carrier stressed devices as well as extensive hydrodynamic device simulations (performed with the code DESSIS [5]) have been adopted