50 GB-capacity dual-layer Blu-ray Disc with GeSbTe based phase-change films

GeSbTe-based thin films showed superior properties for a recording layer of Blu-ray Disc, especially for a front-side recording layer of L1. The film can be thinned to 6 nm with maintaining a rapid phase-transition rate and a large transmittance of >50% was realized in the L1. It is remarkable that transmittances are balanced between in the amorphous and crystalline areas of L1, and it works to remove the optical interference when recording-playing on the rear-side recording layer of L0 through the L1.