Transistor smaller than a nanometre made with crystal growth

Amazing stuff! Smaller, smaller ...

This research was done at a private university, i.e. Pohang University of Science and Technology.

"A team of Korean researchers has built a transistor smaller than a nanometre.

The researchers have figured out how to grow metallic materials 0.4 nanometres in width, and a few tens of micrometres in length, which they have then incorporated into tiny transistors. ..."

"... To solve this technical problem, the research team leveraged the fact that the mirror twin boundary (MTB) of molybdenum disulfide (MoS₂), a 2D semiconductor, is a 1D metal with a width of only 0.4 nm. They used this as a gate electrode to overcome the limitations of the lithography process. ..."

From the abstract:

"In atomically thin van der Waals materials, grain boundaries—the line defects between adjacent crystal grains with tilted in-plane rotations—are omnipresent. When the tilting angles are arbitrary, the grain boundaries form inhomogeneous sublattices, giving rise to local electronic states that are not controlled. Here we report on epitaxial realizations of deterministic MoS2 mirror twin boundaries (MTBs) at which two adjoining crystals are reflection mirroring by an exactly 60° rotation by position-controlled epitaxy. We showed that these epitaxial MTBs are one-dimensionally metallic to a circuit length scale. By utilizing the ultimate one-dimensional (1D) feature (width ~0.4 nm and length up to a few tens of micrometres), we incorporated the epitaxial MTBs as a 1D gate to build integrated two-dimensional field-effect transistors (FETs). The critical role of the 1D MTB gate was verified to scale the depletion channel length down to 3.9 nm, resulting in a substantially lowered channel off-current at lower gate voltages. With that, in both individual and array FETs, we demonstrated state-of-the-art performances for low-power logics. The 1D epitaxial MTB gates in this work suggest a novel synthetic pathway for the integration of two-dimensional FETs—that are immune to high gate capacitance—towards ultimate scaling."

Transistor smaller than a nanometre made with crystal growth

Scientists Discover Way to “Grow” Sub-Nanometer Sized Transistors (original news release) Opening the Path to Next-Generation Semiconductors through Epitaxial Growth of New Van der Waals Materials

Integrated 1D epitaxial mirror twin boundaries for ultrascaled 2D MoS2 field-effect transistors (no public access)

Figure 2. Ultra-miniaturized transistors and integrated circuits using 1D mirror twin boundary gates