Asymmetric DC-magnetron sputtered carbon-nitrogen thin-film overcoat for rigid-disk applications

An asymmetric DC-magnetron sputtering technique was evaluated to deposit carbon-nitrogen (C:N) overcoats for rigid-disk applications. The tribological characteristics of very thin C:N overcoats (~100 Å) were investigated by using thin-film flying inductive heads, Tripad-proximity recording heads, and carbon-coated magneto-resistive (MR)-heads in different test environments. Comparison of >20 K contact start-stop (CSS) test cycles showed superior stiction and durability performance for the asymmetric DC-magnetron sputtered (asym-C:N) films compared to standard symmetric DC-magnetron sputtered (sym-C:N) films. After CSS testing, no visible wear marks and/or head-build up were observed. Comparison of stress and hardness data showed a reduction of internal stress without noticeable change in hardness for asym-C:N films. Also, elemental analysis showed higher nitrogen content in asym-C:N films. In addition, Raman spectroscopy data suggest that the asym-C:N films have higher sp³ content than that of sym-C:N films, which can contribute to greater durability