GaN Nanowire MOSFET With Near-Ideal Subthreshold Slope

Abstract

Wrap-around gate GaN nanowire MOSFETs using Al2O3 as gate oxide have been experimentally demonstrated. The fabricated devices exhibit a minimum subthreshold slope of 60 mV/dec, an average subthreshold slope of 68 mV/dec over three decades of drain current, drain-induced barrier lowering of 27 mV/V, an on-current of 42 μA/μm (normalized by nanowire circumference), on/off ratio over 108, an intrinsic transconductance of 27.8 μS/μm, for a switching efficiency figure of merit, Q=gm/SS of 0.41 μS/μm-dec/mV. These performance metrics make GaN nanowire MOSFETs a promising candidate for emerging low-power applications such as sensors and RF for the internet of things.

Single GaN Nanowires for Extremely High Current Commutation

“…We compared the obtained results with data reported on the drain‐to‐source current density of field‐effect transistors (FETs) based on GaN NWs. An analysis of the published studies [ 31–35 ] devoted to GaN‐NW‐based FETs shows that the drain current density flowing through a single NW is in the range of several tens to several hundreds of kiloamperes per centimeter square, which is an order of magnitude lower than the value reported here.…”

Low Leakage and High ION/IOFF Ratio in Partial Gated AlGaN/GaN Nanowire Field‐Effect Transistors

“…Figure 2b shows the subthreshold drain current of the order of ≈100 fA μm −1 (for G1) for a wide range of gate and drain voltages, which is much less in comparison with that of gate‐all‐around and Ω‐gate configuration of GaN transistors. [ 10,19–24 ] This device provides an I ON / I OFF ratio greater than 10 8 , higher than the best reported value for GaN NWFETs. Figure 2c shows the extremely low gate leakage current for various drain voltages.…”

“…For the DG configuration, an I DS,sat of 35 mA mm −1 at V GS = 3 V and a transconductance of 3 mS mm −1 are observed, which are comparable with those reported in the literature for other GaN‐based NWFETs. [ 10,19,20 ] The threshold voltage is −2.5 V. It is interesting to note that the threshold voltage is not significantly different from that in a conventional AlGaN/GaN heterostructure due to lower AlGaN thickness and 2D gate control. [ 14 ] The wet etching process reduces the AlGaN barrier layer by boiling H 3 PO 4 described earlier.…”

Applications and Research Progress of GaN

“…The wide band gap semiconductor GaN is very suitable material for high frequency, high voltage and high output power field effect transistors (FETs) because of its high saturation electron velocity, high dielectric breakdown voltage and the possibility of constructing heterostructures of AlGaN/GaN to achieve high electron concentration. yu et al [8] fabricated FETs based on GaN nanowire arrays, which have a threshold voltage of 1.5 V and the output current was greater than 10 mA, and Li et al [9] constructed metal-oxide-semiconductor FETs using GaN nanowires grown by molecular beam epitaxy, which had an on/off ratio of up to 108. The above studies demonstrate potential application scenarios for GaN in areas such as next-generation power switches and high-temperature digital circuits.…”