One-hundred-nanometer-gate (Al, In) N/GaN highelectron- mobility transistors (HEMTs) grown on semi-insulating SiC achieve a maximum current density of 1.84 A/mm at V-GS = 0 V, an extrinsic transconductance of 480 mS/mm, and a peak current gain cutoff frequency as high as f(T) = 144 GHz, which is the highest so far reported for any (Al, In) N/GaN-based HEMT. This f(T) matches the best published values that we could find for 100-nm-gate (Al, Ga) N/GaN HEMTs, thus closing the cutoff frequency gap between (Al, In) N/GaN and (Al, Ga) N/GaN HEMTs. Additionally, similar devices grown on (111) highresistivity silicon show a peak fT of 113 GHz, also setting a new performance benchmark for (Al, In) N/GaN HEMTs on silicon. Our findings indicate significant performance advantages for (Al, In) N/GaN HEMTs fabricated on SiC substrates. The improved performance for devices grown on SiC is derived from the superior transport properties of (Al, In) N/GaN 2DEGs grown on that substrate.