Hydrogen Peroxide-Enabled High-Quality Transition Interface for Top-Gated Molybdenum Disulfide Field-Effect Transistors.

Abstract

Two-dimensional (2D) transition-metal dichalcogenides are promising channel materials, but integrating ultrathin high-k gate dielectrics remains challenging because their surfaces lack dangling bonds. Atomic layer deposition (ALD) enables conformal dielectric growth on these 2D materials, with oxidant selection introducing a trade-off between water (H₂O), which yields poor nucleation, and ozone (O₃), which affords uniform coverage at the expense of interface/channel degradation via oxygen substitution. Here, we demonstrate that hydrogen peroxide (H₂O₂)-driven ALD of high-k oxides yields uniform dielectric coverage while minimizing performance degradation by controlling Mo-sulfate formation at the interface on molybdenum disulfide (MoS₂). This chemistry offers nucleation sites while preserving the 2D channel integrity through S-O interfacial bonding. Top-gated MoS₂ field-effect transistors (FETs) with H₂O₂-based ALD hafnium oxide (HfO₂) gate dielectrics achieve steep subthreshold slopes (∼70 mV/dec), low hysteresis (∼42 mV), and an equivalent oxide thickness (EOT) of ∼0.9 nm. Benchmarking shows that these devices exhibit improved performance compared with previously reported single-dielectric top-gated MoS₂ FETs. These findings establish H₂O₂-driven ALD of a high-k dielectric as a promising approach for complementary metal-oxide-semiconductor (CMOS)-compatible 2D gate stacks and suggest that robust S-O interfacial bonding can enable 3D-integrated, low-power device operation.