Thermal Cross-Erase Issues in High-Data-Density Phase-Change Recording

We report on the numerical simulations of high-data-density phase-change recording (DVR-blue and DVR-red) in order to analyse the phenomenon of thermal cross-erase in land/groove recording. In particular, if a maximum data capacity is pursued, which involves a small radial track pitch, thermal cross interference may become an important issue. The question of whether or not the temperature distributions and the related thermal cross-erase probability scale with the optical spot size is addressed. Two different thermal models (a planar model and a land/groove model) were used in which laser heating was simulated. Reliable temperature predictions and related trend analyses require a proper model and accurate input parameters. The thermal conductivity of the different layers in the stack was obtained from measurements performed with a time-resolved static tester setup in combination with a novel melt-threshold method. Since thermal cross-erase is dependent on the temporal temperature distribution in the stack, we analysed the most important parameters that possibly contribute to a reduction of the temperature, and thus the cross-erase probability, in the adjacent track.