Ultra-thin tetrahedral amorphous carbon film as slider overcoat for high areal density magnetic recording

Areal density in magnetic recording has been increasing at a phenomenal rat e over the past 10 years. In order to achieve 10 Gb/in(2) areal density and more, magnetic spacing between the disk and head must be of the order of 3 5 nm or less, which requires 5 nm or less overcoats on both the media and r ecording head air bearing surface (ABS). These overcoats act as protective coatings against corrosion of magnetic alloys as well as wear which may occ ur when the slider contacts the rigid disk during turn-on or shutdown of di sk drive. Tetrahedral amorphous carbon (ta-C) films of 1.5-7.0 nm thickness have been deposited on both Si wafers and recording sliders by a filtered cathodic are (FCA) system. The coatings were analyzed by Raman, cross-secti on TEM, EELS, contact angle and Tencor Flexus Stress Analyzer in order to c haracterize film structure, thickness and uniformity, sp(3) content, densit y, surface energy and stress. Macro-particle contamination was significantl y reduced by process optimization and characterized by an acid etch corrosi on resistance test. The effect of carbon interactions with magnetic layers and causing a magnetic 'dead-layer' were also investigated with a B-H loop tester and high resolution cross-section TEM. Slider/HGA level tests were c onducted in order to evaluate head tribological performance at the head/dis k interface (HDI) and corrosion resistance. These were conducted by Contact Start/Stop (CSS) test and Battelle/Acid etch tests. We conclude that the s ub-5 nm overcoats prepared by FCA are a viable candidate for future high ar eal density giant magnetoresistance (GMR) slider ABS applications. (C) 1999 Elsevier Science S.A. All rights reserved.