Integration of Ultrathin Hafnium Oxide with Clean vdW Interface for 2D Sandwich Heterostructure Electronics

Integrating high-κ dielectrics with low equivalent oxide thickness (EOT) with two-dimensional (2D) semiconductors for low-power consumption van der Waals (vdW) heterostructure electronics remains challenging in meeting both interface quality and dielectric property requirements. Here, we demonstrate the integration of ultrathin amorphous HfOx sandwiched within vdW heterostructures by selective thermal oxidation of HfSe2 precursors. The self-cleaning process ensures a high-quality interface with a low interface state density of 1011~1012 /cm2eV. The synthesized HfOx displays excellent dielectric properties with an EOT of ~1.5 nm, i.e., a high κ of ~16, an ultralow leakage current of 10-6 A/cm2, and an impressively high breakdown field of 9.5 MV/cm. This facilitates low-power consumption vdW heterostructure MoS2 transistors, demonstrating steep switching with a low sub-threshold swing of 61 mV/dec. This one-step integration of high-κ dielectrics into vdW sandwich heterostructures holds immense potential for developing low-power consumption 2D electronics while meeting comprehensive dielectric requirements.