Hillock formation-a novel approach to sputter texturing media disc substrates

A novel approach to sputter texturing media disc substrates is demonstrated. A phenomenon called hillock formation is adopted in this work to make discs for high-density magnetic recording. Hillocks, small solid metal mounds projecting out of the film plane, form when compression stresses in a selected material are relaxed during temperature cycling in a sputter-deposition process. The hillock size, shape, height and areal density can be controlled by substrate temperature, texturing-layer deposition rate and thickness, and sputter gas type and pressure. Excellent contact-start-stop tribological performance exceeding 30 k cycles and glide height as low as 0.75 μinch are demonstrated. The technique and process are accomplished in-situ, prior to underlayer and magnetic layer deposition, significantly simplifying the disc manufacturing process. The implementation of the sputter-texture technique has the potential for lowering head flying height, minimizing disc handling, reducing defects and contamination, and effectively cutting the cost of making discs