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Structure and properties of sputtered carbon overcoats on rigid magnetic media disks

Journal Article · · J. Vac. Sci. Technol., A; (United States)
DOI:https://doi.org/10.1116/1.575581· OSTI ID:7201161

Sputtered carbon overcoats on commercial rigid disks with thin-film magnetic media are studied using transmission electron analysis (microscopy, microdiffraction, and energy-loss spectroscopy), Raman spectroscopy, Auger spectroscopy, ellipsometry, x-ray diffraction, and microhardness testing. Data from transmission electron analysis, Raman spectroscopy, and ellipsometry suggest that the carbon overcoats are composed of small graphite crystallites (less than or equal to2 nm), randomly oriented, with a small percentage (0%--5%) of fourfold coordinated carbon bonds. Auger spectroscopy and transmission electron energy-loss spectroscopy indicate the presence of a small amount of oxygen. Auger spectroscopy also shows some surface nitrogen. The optical constants, n = 2.1 and k = 0.78, exhibit a small wavelength dependence. In addition, the extinction coefficient k shows a dependence upon film thickness. X-ray diffraction and microhardness testing did not yield any information concerning the carbon overcoats. There was no indication of diamond from any of the techniques which distinguish between diamond and other forms of carbon. Differences in structure and bonding are seen with Raman spectroscopy in samples from different manufacturers and in annealed samples.

Research Organization:
Department of Mechanical Engineering, University of California, Berkeley, California 94720
OSTI ID:
7201161
Journal Information:
J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 6:4; ISSN JVTAD
Country of Publication:
United States
Language:
English