High-Current Submicrometer Tri-Gate GaN High-Electron Mobility Transistors With Binary and Quaternary Barriers

Through implementation of the 3-D tri-gate topology, GaN-based high-electron mobility transistors (HEMTs) have been fabricated and high-frequency performances as well as the short-channel effects are investigated. The designed tri-gate transistors are highly-scaled having 100 nm of gate length, which introduces the condition of a short channel. It is demonstrated that higher sub-threshold slopes, reduced drain-induced barrier lowering and better overall off-state performances have been achieved by the nano-channel tri-gate HEMTs with an AlGaN barrier. A lattice-matched InAlGaN barrier with the help of the fin-shaped nano-channels provide improved gate control, increasing current densities, and transconductance gm. In a direct comparison, very high drain current densities (~3.8 A/mm) and gm (~550 mS/mm) have further been obtained by employing a pure AlN barrier.