Borazine Promoted Growth of Highly Oriented Thin Films.

We report on a phenomenon, where thin films sputter-deposited on single-crystalline Al 2 O 3 (0001) substrates exposed to borazine─a precursor commonly used for the synthesis of hexagonal boron nitride layers─are more highly oriented than those grown on bare Al 2 O 3 (0001) under the same conditions. We observed this phenomenon in face-centered cubic Pd, body-centered cubic Mo, and trigonal Ta 2 C thin films grown on Al 2 O 3 (0001). Interestingly, intermittent exposure to borazine during the growth of Ta 2 C thin films on Ta 2 C yields better crystallinity than direct deposition of monolithic Ta 2 C. We attribute these rather unusual results to a combination of both enhanced adatom mobilities on, and epitaxial registry with, surfaces exposed to borazine during the deposition. We expect that our approach can potentially help improve the crystalline quality of thin films deposited on a variety of substrates.