Near-Amorphous Alloy Thin Films by Co-Sputtering Deposition

Four alloy thin films were deposited on Si(100) by co-sputtering of various metals to investigate the formation of near-amorphous structure which may lead to featureless surface morphology and boundary-free structure. These thin films, Nb-Cr, Ta-Cr, Ti-Nb, and Zr-Cr, were examined using XRD SEM, and TEM. It is found that the forming ranges of near-amorphous thin films by co-sputtering are related to the difference in atomic size of the paired metals as well as their heat of mixing. Accordingly, Zr-Cr has the widest concentration range to form the near-amorphous structure. The addition of nitrogen during deposition can further enhance amorphization and reduce the surface roughness, until nitride phases are formed.