Enhancement-Mode Lattice-Matched AlInN/GaN/AlGaN/GaN Heterostructured-Fin-Gated Multichannel and Double-Channel MOSHEMTs

To simultaneously achieve high sheet electron density and high electron mobility, vertically laminated lattice-matched AlInN/GaN/AlGaN/GaN heterostructured double two-dimensional electron gas (2DEG) channels were grown on silicon substrates. Using the epitaxial layers and the advantage of high gate control capability, various wide fin-gated multichannel structures were manufactured. When ferroelectric stacked LiNbO3/HfO2/Al2O3 films were utilized as gate oxide layers, enhancement-mode fin-gated multichannel and double-2DEG channels metal-oxide-semiconductor high-electron mobility transistors (MOSHEMTs) were fabricated. Compared the planar devices with the 80-nm-wide multichannel devices, the normalized drain-source current increased from 273.7 mA/mm to 701.3 mA/mm, the subthreshold swing improved from 218 mV/dec to 96 mV/dec, the maximum transconductance improved from 100.8 mS/mm to 270.3 mS/mm, and the threshold voltage shifted from 2.1 V toward 2.5 V. By utilizing the fin-gated multichannel structure, not only could the double-hump transconductance characteristics of planar devices be transferred into smooth single-hump transconductance characteristics, but low-frequency noise power density could also be reduced and high-frequency characteristics improved. Furthermore, the fin-gated multichannel devices with narrower channel width exhibited better characteristics.