Papers by Author: Y.C. Liu

Abstract: 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.

Abstract: A quantitative approach to determination of depth profiles of optical properties of Si-implanted SiO2 films based on spectroscopic ellipsometry (SE) is presented. From the SE measurements, the depth profiles of the complex refractive index of SiO2 films containing Si nanocrystals (Si-nc) are obtained with an effective medium approximation (EMA) in the wavelength range of 400-1200nm. The optical profiles obtained imply the existence of a wave-guide in the Si-doped SiO2 films.