Functionalized ion-beam carbon for magnetic disks

Abstract

Summary form only given. Carbon overcoat thickness is continuously being decreased to achieve higher areal density in magnetic media. For present and future products, the thickness of the carbon overcoat has been reduced to 30 /spl Aring/ or less. These thin carbon films have to be robust enough to effectively protect the media against wear and corrosion. The carbon overcoat consists of two interfaces: an interface with the magnetic layer and the carbon-lubricant interface. Both mechanical/chemical properties of the carbon overcoat and its surface reactivity affect the carbon-lubricant bonding which subsequently affects the lubricant-head interaction. Functionalized carbon overcoat consists of a base layer of ion beam carbon (IBC) and a top thinner layer of nitrogenated sputtered carbon. In the IBC process, hydrocarbon (C/sub x/H/sub y/) gas is used as a precursor. High hydrogen content in the film increases the electrical resistivity which could potentially lead to charge buildup on the surface, resulting in head damage. High hydrogen content also can decrease the dangling bond density in the carbon layer resulting in lower carbon lubricant bonding, leading to lube pick-up by the head. With the use of thin hard carbon overcoats, glide head-disk interactions (glide noise) and head degradation issues are becoming severe. These issues could be addressed by doping the top layer of the functional carbon layer (sputtered) with nitrogen.