Gate-Length Dependence of DC Characteristics in Submicron-Gate AlGaN/GaN High Electron Mobility Transistors

We investigated the gate-length dependence of room-temperature DC operation in submicron-gate AlGaN/GaN high-electron-mobility transistors (HEMTs). The threshold voltage was reduced by the short-channel effect, which is only dependent on the aspect ratio of the gate length to the barrier-layer thickness. On the other hand, the transconductance was restricted by the source resistance, and was dependent on not only the gate length L G but also the source–gate length L SG . The transconductance was increased by reducing L SG rather than L G in the submicron-gate HEMTs.