Few-Layered MoS<sub>2</sub> Field-Effect Transistors with a Vertical Channel of Sub-10 nm
Xiao Ping Zou, Lu Liu, Jing-Ping Xu, Hongjiu Wang, Wing-Man Tang
Abstract
Few-layered molybdenum disulfide (MoS2) has demonstrated promising advantages for the integration of next-generation electronic devices. A vertical short-channel MoS2 transistor with a channel length of sub-10 nm can be realized using mica as the insulated mesa and MoS2 flake dry-transferred onto the mica as the channel. A near-perfect symmetrical and fully saturated output characteristic can be obtained for the positive or negative drain–source voltage. This result is attributed to an effective transformation of the drain–source electrode contact from Schottky contact to Ohmic contact via forming gas annealing. The vertical-channel MoS2 transistor with a channel length of 8.7 nm exhibits excellent electrical characteristics, for example, a negligible hysteresis voltage of 60 mV, an extraordinarily small subthreshold swing of 73 mV/dec, a considerably weakened drain-induced barrier-lowering effect (100 mV/V), and the first-reported intrinsic delay time of 2.85 ps. Moreover, a logic inverter can be realized using the two vertical-channel MoS2 transistors, with a high voltage gain of 33. Experimental results indicate that the developed method is a potential approach for fabricating MoS2 transistors with an ultrashort channel and high performance, and consequently, manufacturing MoS2-based integrated circuits.