AlGaN/GaN HEMTs on SiC with fT of over 120 GHz

AlGaN/GaN high electron mobility transistors (HEMTs) grown on semi-insulating SiC substrates with a 0.12 μm gate length have been fabricated. These 0.12-μm gate-length devices exhibited maximum drain current density as high as 1.23 A/mm and peak extrinsic transconductance of 314 mS/mm. The threshold voltage was -5.2 V. A unity current gain cutoff frequency (f
_T
) of 121 GHz and maximum frequency of oscillation (f
_max
) of 162 GHz were measured on these devices. These f
_T
and f
_max
values are the highest ever reported values for GaN-based HEMTs.