High performance 0.25 [micro sign]m gate-length AlGaN∕GaN HEMTs on 6H-SiC with power density of 6.7 W∕mm at 18 GHz

Abstract

MOCVD-grown 0.25 µm gate-length AlGaN/GaN high electron mobility transistors (HEMTs) have been fabricated on 6H-SiC substrates. These 0.25 µm gate-length devices exhibited maximum drain current density as high as 1.28 A/mm, peak extrinsic transconductance of 310 mS/mm, unity current gain cutoff frequency ( fT) of 51 GHz, and maximum frequency of oscillation ( fmax) of 115 GHz. At 18 GHz, a continuous-wave output power density of 6.7 W/mm with power-added efficiency of 26.6% was obtained, yielding the highest reported power performance of AlGaN/GaN HEMTs at 18 GHz.