AbstractAn AlGaN/GaN hetero field effect transistor (HFET) was operated at 20 A. Its on-state resistance was lower than that of a Si-based FET. GaN and related materials were grown by gas-source molecular beam epitaxy (GSMBE). Sapphire substrates were used for GaN growth. An undoped GaN/Al0.2Ga0.8N heterostructure wasgrown on the substrate. The sheet carrier density of two dimensional electron gas was 1x1013 cm2 and the mobility was 1200 cm2/Vs at room temperature. The breakdown field of undoped high resistive GaN layer was about 2.0 MV/cm. Al0.2Ga0.8N/GaN HFET for a large current operation was fabricated. The gate width was 20 cm and thegate length was 2000 nm. The electrode material of the source and the drain was Al/Ti/Au and the Schottky electrodes were Pt/Au. The distance between the source and the drain was 6000 nm. The maximum breakdown voltage of gate and source was 600 V. The on-state resistance of the HFET was about 2 mohm•cm2 at 100 V. The transconductance (gm) of this HFET was about 120 mS/mm. It was confirmed that the HFET with a gate width of20 cm could be operated at the condition of a large current operation.
