Control of surface oxidation layer thickness in metal evaporated tapes

The formation mechanisms of the surface oxidation layer and the oxidation i nside metal evaporated tapes have been clarified, The Auger depth profiles of the samples deposited with various geometric arrangements of the oxygen gas flow nozzle were investigated. The surface oxidation layer is influence d by the oxygen partial pressure distribution around the can roll near the nozzle. The internal oxidation of the film is caused by the diluted oxygen gas after diffusion around the can roll. The results suggest that oxygen ga s heating will cause a reduction in the thickness of the surface oxidation layer. The introduction of high-temperature metal vapor and radiant heat in to the nozzle is effective in decreasing the thickness of the surface oxida tion layer and significantly improves the playback output levels, particula rly at short recording wavelengths.