Low Ohmic Contact Resistance m-Plane AlGaN/GaN Heterojunction Field-Effect Transistors with Enhancement-Mode Operations

Low ohmic contact resistance m-plane AlGaN/GaN heterojunction field-effect transistors were demonstrated using a regrown n(+)-GaN contact layer. An ohmic contact resistance of 0.25 Omega.mm was obtained with an 80-nm-thick Si-doped regrown GaN contact layer deposited by metal organic chemical vapor deposition. Enhancement-mode m-plane AlGaN/GaN heterojunction field-effect transistors were demonstrated with a threshold voltage of +1.4 V and 2.0m Omega.cm(2) on-state resistances at +5 V of gate-source voltage. (C) 2010 The Japan Society of Applied Physics