Effect of naturally adsorbed gas on substrate surface on the growth of very thin WCr seedlayer

The effect of naturally adsorbed gas on an NiP-Al substrate surface on the growth of a very thin WCr seedlayer and the effect of growth form of a WCr seedlayer on the microstructure and properties of magnetic recording media have been studied. An Auger electron spectroscopy analysis result clarifies that the critical thickness at which the WCr seedlayer changes from island-like to continuous layer is 2.5 and 1.5 nm when grown on the substrate surface with and without naturally adsorbed gas, respectively. The result means that the NiP-Al substrate surface with adsorbed gas enhances the island-like growth of the WCr seedlayer, probably due to the reduction of mobility of sputtered WCr particles when they react with the adsorbed gas on a substrate surface. It is found that the media grain size and the media noise are reduced only when using a WCr seedlayer thinner than 1.25 nm fabricated on substrate surface with adsorbed gas.