Reduction of low-frequency noise in multilayer MoS2 FETs using a Fermi-level depinning layer

Two‐dimensional transition metal dichalcogenides (TMDCs) are potential candidate materials for future thin‐film field effect transistors (FETs). However, many aspects of this device must be optimized for practical applications. In addition, low‐frequency noise that limits the design window of electronic devices, in general, must be minimized for TMD‐based FETs. In this study, the low‐frequency noise characteristics of multilayer molybdenum disulphide (MoS2) FETs were investigated in detail, with two different contact structures: titanium (Ti) metal–MoS2 channel and Ti metal–TiO2 interlayer–MoS2 channel. The results showed that the noise level of the device with a TiO2 interlayer reduced by one order of magnitude compared with the device without the TiO2 interlayer. This substantial improvement in the noise characteristics could be explained using the carrier number of fluctuation model. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) The low‐frequency noise mechanism in multilayer MoS2 FETs with two different contact systems is investigated; Ti metal–MoS2 channel and Ti metal–TiO2 interlayer–MoS2 channel, respectively. The reduced noise level (∼10–11 @ 10 Hz) with TiO2 interlayer is much lower than the 1/f noise requirement (∼10–9 @ 10 Hz) for Si CMOS technology specified in International Technology Roadmap for Semiconductor (ITRS). Thus, as a conclusion, the insertion of thin TiO2 layer is playing a crucial role in the reduction of noise amplitude as well as the contact resistance for TMD‐based 2D devices.