High-Performance Wafer-Scale MoS Transistors toward Practical Application.

Atomic thin transition-metal dichalcogenides (TMDs) are considered as an emerging platform to build next-generation semiconductor devices. However, to date most devices are still based on exfoliated TMD sheets on a micrometer scale. Here, a novel chemical vapor deposition synthesis strategy by introducing multilayer (ML) MoS islands to improve device performance is proposed. A four-probe method is applied to confirm that the contact resistance decreases by one order of magnitude, which can be attributed to a conformal contact by the extra amount of exposed edges from the ML-MoS islands. Based on such continuous MoS films synthesized on a 2 in. insulating substrate, a top-gated field effect transistor (FET) array is fabricated to explore key metrics such as threshold voltage (V ) and field effect mobility (μ ) for hundreds of MoS FETs. The statistical results exhibit a surprisingly low variability of these parameters. An average effective μ of 70 cm V s and subthreshold swing of about 150 mV dec are extracted from these MoS FETs, which are comparable to the best top-gated MoS FETs achieved by mechanical exfoliation. The result is a key step toward scaling 2D-TMDs into functional systems and paves the way for the future development of 2D-TMDs integrated circuits.