Reliability of High-Performance Monolayer MoS2 Transistors on Scaled High-κ HfO2

The successful integration of ultrathin high-κ insulators is essential for the advancement of ultra-scaled field-effect transistors (FETs) based on two-dimensional (2D) semiconductors in future technology nodes. However, defects within the high-κ stack or at the interfaces can significantly degrade the performance of these “interface-only” devices, raising questions regarding their long-term reliability. Here, we study the reliability of monolayer MoS 2 FETs on ultra-thin high-κ HfO 2 . Interestingly, we observe a two-stage threshold voltage shift (Δ V TH ) under positive bias temperature stress (PBTS) and hot carrier degradation (HCD), attributed to electron trapping in preexisting traps and the generation of hydrogen-assisted donor traps within the gate oxide. In contrast, devices fabricated on exfoliated hBN lack this two-stage Δ V TH , implying such donor trap generation is induced by atomic-layer-deposition (ALD) processes used in HfO 2 -based devices. Refining the ALD process emerges as a key strategy for enhancing the stability of 2D FETs to meet silicon CMOS standards.