Roughness studies of ion beam processed molybdenum surfaces

• Published in: Journal of applied physics 1986, Vol.59 (1), p.257-262
• Main Authors: BU-ABBUD, G. H, MATHINE, D. L, SNYDER, P, WOOLLAM, J. A, POKER, D, BENNETT, J, INGRAM, D, PRONKO, P. P
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Ion radiation effects; Materials science; Metals, semimetals and alloys; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Physical radiation effects, radiation damage; Physics; Specific materials; Structure of solids and liquids; crystallography
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.336873

Mechanically polished molybdenum samples have been irradiated with 150 keV molybdenum ions at fluences from zero to 16×1015 ions/cm2 to study the effects on surface smoothing. Both fluence and substrate temperature during irradiation (25, 250, and 500 °C) had considerable effects on the optical properties. Ellipsometry, profilometry, and Nomarski photography were used to characterize the surfaces. Multiple wavelength, multiple angle of incidence ellipsometry results were analyzed using effective medium approximation models, with molybdenum, molybdenum oxide, and voids as the principal constituents. Generally, we find that the reflectance calculated from the ellipsometric measurements increases continuously as a function of fluence. However, for high substrate temperature and short wavelength the reflectance as a function of fluence reaches a maximum and then decreases. Effective medium calculations indicate that there is a corresponding change in the surface roughness with fluence, and that effects due to oxides are minimal.