Atomic layer epitaxy of twinned TiN by hydrogen-manipulated tailoring on monolayer

This study demonstrates the atomic layer epitaxial growth of titanium nitride (TiN) with a record-low resistivity (8.2×10−8Ω∙m) by hydrogen-manipulated chemical reaction on each monolayer. The incorporation of hydrogen plasma at a specific time during atomic layer deposition is critical to activate the epitaxial growth at only 300 °C, as evidenced by X-ray diffraction pole figure and high-resolution/scanning transmission electron microscopy. The lattice misfit is relaxed within just few monolayers away from the TiN/substrate interface. An "island plus layer" mode is proposed to explain the growth of TiN, which is intrinsically composed of twins. The low resistivity and high crystallinity of the TiN epitaxial layer manifest the significant impact of the time-manipulated hydrogen tailoring on material properties. Furthermore, the hydrogen-manipulated atomic layer epitaxy benefits from large-area uniformity, low growth temperature, and no need for high-vacuum operation, which are more advantageous over molecular beam epitaxy and so exhibit promising prospects in diverse applications.