Ballistic and tunneling GaAs static induction transistors: nano-devices for THz electronics

Abstract

GaAs static induction transistors (SIT) with 10-nm scale channel and with a 100-nm channel were fabricated with molecular layer epitaxy (MLE). Area-selective epitaxy of GaAs/AlGaAs/GaAs was used for the gate. Temperature dependence of current-voltage (I-V) characteristics of the 100-nm SIT indicates ballistic injection of electrons. In the 10-nm scale SIT, electrons are transported ballistically in the drain-side electric field. Direct tunneling is responsible for the transport through the potential barrier. It is indicated by the temperature dependence and by the electroluminescence spectrum. Electron transport in the 10-nm scale SIT is nearly scattering-free. The plausible estimation of the electron transit time is 2/spl middot/10/sup -14/ s; the worst case estimation based on saturated drift velocity gives 1/spl middot/10/sup -13/ s. It makes the ISITs suitable for THz applications. Multiple area-selective MLE GaAs regrowth was used as a tool for automatic definition of the channel length.