Ultrathin LiF insertion and ensued contact resistance reduction in MoS2 channel transistors

Abstract

Molybdenum disulfide (MoS2) is a representative two dimensional n‐type semiconductor for various electron devices, but its lateral conduction performances are still restricted, which is mainly attributed to the contact resistance (Rc) in field‐effect transistor. Low‐enough Rc value must be realized toward practical device fabrications. Here, we have fabricated 2D MoS2 FETs using chemical vapor deposited (CVD) MoS2 channels with and without the ultrathin LiF interlayer, to demonstrate the practical benefits of LiF. In addition, we also apply the LiF to Al metal which is known more earth‐abundant than Au, expecting the similar positive effects of the inserted LiF. When 35 CVD‐grown MoS2 channel FETs with Au were characterized on an identical gate dielectric substrate, the higher value of mobility ranging 55∽60 cm2/V s are achieved with the inserted LiF than that without LiF (∽20 cm2/V s). In the case of another MoS2 FET with exfoliated flake channel and Al contact, its field‐effect mobility with LiF insertion appears to be ∽35 cm2/V s approaching to an almost Rc‐free mobility (42 cm2/V s).This article is protected by copyright. All rights reserved.