Modulation of Contact Resistance of Dual‐Gated MoS<sub>2</sub> FETs Using Fermi‐Level Pinning‐Free Antimony Semi‐Metal Contacts
Tien Dat Ngo, Tuyen Huynh, Hanggyo Jung, Fida Ali, Jongwook Jeon, Min Sup Choi, Won Jong Yoo
Abstract
Abstract Achieving low contact resistance ( R C ) is one of the major challenges in producing 2D FETs for future CMOS technology applications. In this work, the electrical characteristics for semimetal (Sb) and normal metal (Ti) contacted MoS 2 devices are systematically analyzed as a function of top and bottom gate‐voltages ( V TG and V BG ). The semimetal contacts not only significantly reduce R C but also induce a strong dependence of R C on V TG , in sharp contrast to Ti contacts that only modulate R C by varying V BG . The anomalous behavior is attributed to the strongly modulated pseudo‐junction resistance ( R jun ) by V TG , resulting from weak Fermi level pinning (FLP) of Sb contacts. In contrast, the resistances under both metallic contacts remain unchanged by V TG as metal screens the electric field from the applied V TG . Technology computer aided design simulations further confirm the contribution of V TG to R jun , which improves overall R C of Sb‐contacted MoS 2 devices. Consequently, the Sb contact has a distinctive merit in dual‐gated (DG) device structure, as it greatly reduces R C and enables effective gate control by both V BG and V TG . The results offer new insight into the development of DG 2D FETs with enhanced contact properties realized by using semimetals.