94-GHz Large-Signal Operation of AlInN/GaN High-Electron-Mobility Transistors on Silicon With Regrown Ohmic Contacts

We report the first 94-GHz (W-band) large-signal performance of AlInN/GaN high-electron-mobility transistors (HEMTs) grown on high-resistivity silicon (111) substrates. A maximum output power density of 1.35 W/mm and peak power-added-efficiency of 12% are measured at 94 GHz. The devices exhibit a dc maximum current drain density of 1.6 A/mm and a peak transconductance of 650 mS/mm. In small-signal operation, cutoff frequencies f_T/f_MAX = 141/232 GHz are achieved. The large-signal performance of our AlInN/GaN HEMTs on silicon at 94 GHz stills lags the best reported results one on SiC substrates but nevertheless confirms the tremendous interest of GaN-on-Si HEMT technology for low-cost millimeterwave electronic applications.