AlGaN Channel High Electron Mobility Transistors: Device Performance and Power-Switching Figure of Merit

In this paper, AlGaN channels for high electron mobility transistors (HEMTs) have been evaluated based on a power device figure of merit. AlGaN-channel HEMTs grown on SiC substrates by plasma-assisted molecular beam epitaxy (PAMBE) were fabricated. Maximum saturation current of 0.55 A/mm was obtained at V GS =1 V. Current-gain cutoff ( f t ) and power-gain cutoff ( f max ) frequencies obtained from small signal measurements were f t =13.2 GHz and f max =41 GHz. Pulsed current–voltage ( I – V ) measurements at 200 ns showed no dispersion in I – V curves. Large signal continuous wave (CW) measurement yielded an output power density of 4.5 W/mm with power added efficiency (PAE) of 59% at 4 GHz. This work demonstrates the potential of AlGaN channel HEMTs for high voltage switching and microwave power applications.