AlN/GaN/InGaN coupling-channel HEMTs with steep subthreshold swing of sub-60 mV/decade

This work reports an AlN/GaN/InGaN high electron mobility transistor (HEMT) with a steep subthreshold swing (SS) of sub-60 mV/dec utilizing a coupling-channel architecture. The fabricated transistors show a negligible hysteresis, a SS of 39 mV/dec, a large gate voltage swing of >4.2 V, and achieving an excellent quality factor Q = g_m/SS of 6.3 μS-dec/μm-mV. The negative differential resistance effect was found in the subthreshold region in the gate current–voltage (I_g–V_GS) curve. The hot carrier transfer mechanism that occurred in the turn-on/pinch-off progress of the CC-HEMT under the dual-directional sweep, proved by the V_DS- and L_g-dependent bi-directional transfer I–V characteristics, can be responsible for these excellent device performances. This work is believed to encourage further study of the AlN/GaN platform to power the future group III-nitrides CMOS technology.