Dual-Layer Rewritable Phase-Change Recording Media for HD DVD System

We have investigated the recording characteristics of the dual-layer phase-change recording media for a system that uses the blue-violet laser (wavelength of 405 nm), with the numerical aperture of 0.65 and light incidence on 0.6-mm-thick substrate having the land and groove format (HD DVD). In order to achieve higher storage density for its beam spot size, a number of technologies have been incorporated into the media, such as the bismuth-substituted pseudobinary GeSbTe alloy recording film and hafnium oxide-based interface layer material. The feasibility of the user capacity of 36 GB has been successfully demonstrated.