Lawrence Berkeley National Laboratory

Amorphous carbon films are used as protective coatings on magnetic media to protect the magnetic layer from wear and abrasion caused by the read/write head during hard disk drive start-up and operation. A key requirement in increasing the storage capacity and reliability of hard-disk drives is improving the performance of these coatings. This cooperative agreement used optical characterization techniques developed at LBNL to study thin-film hard disk media produced by Seagate Technology, major US hard drive manufacturer. The chief scientific goal was relating quantitatively the results of the optical characterization to the underlying chemical structure of the overcoat. In a collaboration with Seagate, LBNL, and Cambridge University, optical and electron-based characterization were used to evaluate the chemical structure of overcoats. The sp3 fraction of the sputtered amorphous carbon films was measured quantitatively for the first time and related to the optical spectroscopy results. This work and other selected aspects of the research performed under the agreement were presented at technical meetings and published in the open literature. The chief technical goal was designing manufacturing processes for the protective carbon overcoat for use in new generations of Seagate disk drives. To this end, joint research carried out under this agreement enabled Seagate to speed development of new coatings which are currently being used in the production of disk media in Seagate's disk-media manufacturing plants in Fremont, CA.