Optimization of sputtering conditions for protective carbon thin films of rigid disks deposited by FTS

Carbon thin films were deposited on rigid disks as protective layers by fac ing targets sputtering (FTS), and their characteristics were evaluated to d etermine whether they would be suitable protective layers for thin-film mag netic recording disks. The performance and lifetime of a hard disk drive ar e intimately related to the head-disk interface, increase in performance du e to reduction of the flying height and magnetic spacing, and longer produc t lifetime are related to the properties of protective layers covering the surfaces of hard disks. Currently, such layers are generally sputtered amor phous carbon films whose characteristics are strongly dependent on various sputtering conditions, such as the Ar gas pressure, substrate temperature, and de and rf bias voltages. FTS systems are known to have excellent charac teristics such as plasma-free substrates and low working gas pressures in t he order of 0.1 mTorr. Thus, very smooth and uniform thin films can be obta ined, in this study, the dependence of the characteristics of carbon films on the FTS conditions was investigated The carbon films were deposited at A r gas pressures in the range of 0.2 to 10 mTorr and a substrate temperature of 25 degrees C as room temperature, with several de and rf bias voltages and also without any bias voltage. The properties of the films were charact erized by Raman spectroscopy, scanning electron microscopy, and mechanical durability testing. Consequently, carbon films deposited, without plasma damage by FTS, at an A r gas pressure of 0.2 m Torr showed a diamond-like carbon and a microscopic ally flat surface. The relationship between the sputtering conditions and t he carbon films characteristics was also systematically clarified for the f irst time. (C) 1998 Elsevier Science Ltd. All rights reserved.