Computational analysis of cross-erase phenomena for high-density phase-change recording

In accordance with the increase of the recording density of DVD media, the track pitch is required to be smaller and the cross-erase phenomena becomes more prominent. In order to realize large capacity by using the land-and-groove recording format, it is essential to suppress the magnitude of the cross-erasure. In this paper, the computational analysis to estimate the mark and erasure shapes is described and the cross-erase phenomenon obtained from the analysis is discussed in terms of the duty ratio of land width to groove (L/G). The computational analysis mainly consists of two parts, the electromagnetic analysis and thermal analysis. The former computes the electromagnetic field induced from the incident beam by using the finite difference time domain (3D-FDTD) method. The latter simulates the temperature distributions by the finite volume method (3D-FVM). The cross-erase phenomenon is observed by mapping the mark and erasure areas that are obtained from the transient results of temperature distributions.