Recessed-Gate Enhancement-Mode AlGaN/GaN Heterostructure Field-Effect Transistors on Si with Record DC Performance

Abstract

Enhancement-mode devices are in the centre of current research on group-III nitride transistors. The realisation of high-performance enhancement-mode transistors via gate recessing requires damage-free processing. We report on enhancement-mode AlGaN/GaN-on-Si heterostructure field-effect transistors (HFETs) fabricated with a damage-free digital etch technique. The threshold voltage (Vth) achieved is as high as +0.5 V. For AlGaN/GaN-on-Si HFETs, a record extrinsic transconductance (gm) of 420 mS/mm and a record maximum drain current Idmax of 500 mA/mm have been demonstrated. Furthermore, proper turn-off characteristics have been realised. Pulsed I–V characteristics reveal nearly no current collapse.