2D fin field-effect transistors integrated with epitaxial high-k gate oxide.

Precise integration of two-dimensional (2D) semiconductors and high-dielectric-constant (k) gate oxides into three-dimensional (3D) vertical-architecture arrays holds promise for developing ultrascaled transistors 1-5 , but has proved challenging. Here we report the epitaxial synthesis of vertically aligned arrays of 2D fin-oxide heterostructures, a new class of 3D architecture in which high-mobility 2D semiconductor fin Bi 2 O 2 Se and single-crystal high-k gate oxide Bi 2 SeO 5 are epitaxially integrated. These 2D fin-oxide epitaxial heterostructures have atomically flat interfaces and ultrathin fin thickness down to one unit cell (1.2 nm), achieving wafer-scale, site-specific and high-density growth of mono-oriented arrays. The as-fabricated 2D fin field-effect transistors (FinFETs) based on Bi 2 O 2 Se/Bi 2 SeO 5 epitaxial heterostructures exhibit high electron mobility (μ) up to 270 cm 2  V -1  s -1 , ultralow off-state current (I OFF ) down to about 1 pA μm -1 , high on/off current ratios (I ON /I OFF ) up to 10 8 and high on-state current (I ON ) up to 830 μA μm -1 at 400-nm channel length, which meet the low-power specifications projected by the International Roadmap for Devices and Systems (IRDS) 6 . The 2D fin-oxide epitaxial heterostructures open up new avenues for the further extension of Moore's law.