AlGaN/GaN HEMTs on Si(111) with 6.6 W/mm output power density

Al0.27Ga0.73N/GaN HEMTS have been realised on resistive S(111) substrates. The epitaxial structure was grown by MBE yielding a channel mobility of 1440 cm(2)/Vs (room temperature) and a sheet carrier density of 9.6c12 cm(-2). Large signal evaluation of transistors with gate length of 0.25 mum and gate width of 2 x 125 mum yields up to 1.65 W CW output power at 2 GHz corresponding to a power density of 6.6 W/mm. These results arc thought to represent the highest output power density so far achieved for GaN-based HEMTs on silicon substrates.