Wafer-Scale Demonstration of BEOL-Compatible Ambipolar MoS2 Devices Enabled by Plasma-Enhanced Atomic Layer Deposition

Abstract

The relentless scaling of semiconductor technology demands materials beyond silicon to sustain performance improvements. Transition metal dichalcogenides (TMDs), particularly MoS2, offer excellent electronic properties; however, achieving scalable and CMOS-compatible fabrication remains a critical challenge. Here, we demonstrate a scalable and BEOL-compatible approach for the direct wafer-scale growth of MoS2 devices using plasma-enhanced atomic layer deposition (PE-ALD) at temperatures below 450 °C, fully compliant with CMOS thermal budgets. This method enables the fabrication of MoS2-based devices directly on target substrates, eliminating material transfer while ensuring robust adhesion and integration with semiconductor processing. The resulting field-effect transistors (FETs) exhibit stable ambipolar behavior, consistent across semiconductor thickness variations and environmental conditions. Electrical characterization reveals minimal Fermi-level pinning, with Schottky barrier heights below 120 meV for both carriers, supporting a well-defined thermionic transport regime. Low-frequency noise measurements confirm flicker noise characteristics, typical of planar field-effect devices. Material conductivity is significantly enhanced through in situ, BEOL-compatible dielectric passivation or sulfur-atmosphere annealing. This work highlights the potential to directly fabricate, lithographically pattern, and encapsulate MoS2 devices for three-dimensional (3D) integration, fully compliant with silicon CMOS thermal constraints.