Disc media

摘要

A thin-film disc fabrication method and structure contemplates a sputtered undercoat. An aluminum base is subjected to a fine polishing step, and a relatively thin undercoat is deposited by sputtering. The preferred undercoat is a 0.3-3 micron layer of nickel-vanadium alloy (on the order of 7% vanadium). The preferred recording layer is a sputtered composite structure comprising a layer of chromium and an overlying layer of a cobalt-chromium alloy. Modulation effects can be substantially eliminated by heating the aluminum base prior to sputtering the nickel-vanadium undercoat, and by oxidizing the undercoat prior to deposition of the overlying layers.