Synergistic semimetal and mesa-architecture engineering for low-resistance contacts in wafer-scale MOCVD MoS2 FETs

초록

Two-dimensional (2D) transition metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS2), have emerged as promising semiconducting materials for next-generation electronics, offering exceptional atomic-scale electronic properties. Despite these advantages, the advancement of scalable 2D MoS2-based electronics remains hindered by distinct challenges including high contact resistance and strong Fermi level pinning (FLP) at metal-semiconductor (M − S) interfaces. In this study, the influence of various contact strategies on the electrical characteristics of monolayer MoS2-based FETs was systematically investigated, including various metals (Ti, Ni, Au, Sb), contact geometries (planar, mesa), and measurement conditions (ambient, vacuum). To further improve contact quality and device performance, the effects of post-process treatments, such as forming gas annealing (FGA), were also examined. Continuous MoS2 monolayers were grown on SiO2/Si substrates via metal-organic chemical vapor deposition (MOCVD) to evaluate these strategies on an industrially scalable platform. Our results demonstrate that the Sb-mesa configuration enables a significant reduction in contact resistivity by nearly three orders of magnitude compared to conventional Ti-planar contacts. This substantial improvement is attributed to the mesa contact configuration, which mitigates the van der Waals (vdW) gap and enhances carrier injection efficiency by optimizing the band alignment, thereby enabling superior metal-semiconductor coupling and significantly improving the overall electrical properties. These findings offer a pathway for overcoming FLP and achieving scalable, low-resistance contacts in 2D material-based electronics, positioning this approach as a key enabler for future high-performance device integration. © 2026

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