DLC deposition parameters optimization for head disk design interface with a thermal protrusion slider from tribological point of view

This paper will study the effects of plasma enhanced chemical vapor deposition (PECVD) parameters (source gas type, gas flow rate, substrate bias voltage and emission current) of diamond-like carbon (DLC) films on tribological properties with a thermal protrusion slider for use in designing next generation disk. The purpose of the study is to achieve robust tribological properties between the HDI optimized by using the Taguchi experimental design method and Grey relational analysis. This study will investigate the microstructure, hardness and lubricant bonded properties of the DLC film which will be correlated to the wear resistance of the disk and slider of the HDI. Based on the analysis, the deposition process parameters of the source gas type and substrate bias voltage are the most significant factors on SNR related to Id/Ig, hardness and lube bonded ratio of DLC films, disk wear density and head slider delta touch-down power, respectively. DLC film with a higher hardness and lube bonded ratio can enhance the disk wear resistance. The higher lube bonded ratio and the lower hardness of DLC films result in lower slider delta touch-down power (or a better slider wear resistance). There is a good correlation among Id/Ig, lube bonded ratio, disk wear density and slider delta touch-down power. Simultaneously, to optimize the disk wear density and the slider delta touch-down power for head disk design interface with a thermal protrusion slider, the optimum wear resistance of disk and slider were obtained using a C2H2 source gas, 25 sccm flow rate, −60 V substrate bias voltage and 0.5 A emission current, respectively.

► Taguchi method and Grey relational analysis are used in this study.
► The optimal DLC deposition parameters are C2H2 source gas, 25 sccm gas flow, −60 V substrate bias and 0.5 A emission current.
► Compared with current design, optimum design was able to reduce 78% at disk wear density and 49% at slider touch-down power.
► The source gas type is the most significant factor with a 36.9% contribution.