Au-Free GaN High-Electron-Mobility Transistor with Ti/Al/W Ohmic and WN_X Schottky Metal Structures for High-Power Applications

In this study, an Au-free AlGaN/GaN high-electron-mobility transistor (HEMT) with Ti/Al/W ohmic and WNx Schottky metal structures is fabricated and characterized. The device exhibits smooth surface morphology after metallization and shows excellent direct-current (DC) characteristics. The device also demonstrates better performance than the conventional HEMTs under high voltage stress. Furthermore, the Au-free AlGaN/GaN HEMT shows stable device performance after annealing at 400°C. Thus, the Ti/Al/W ohmic and WN_X Schottky metals can be applied in the manufacturing of GaN HEMT to replace the Au based contacts to reduce the manufacturing costs of the GaN HEMT devices with comparable device performance.