Work

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

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The relentless scaling of semiconductor technology demands materials beyond silicon to sustain performance improvements. Transition metal dichalcogenides (TMDs), particularly MoS 2, 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 MoS 2 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 MoS 2 -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 MoS 2 devices for three-dimensional (3D) integration, fully compliant with silicon CMOS thermal constraints.

Source: ACS Applied Materials & Interfaces

DOI: 10.1021/acsami.5c12014