Determination of the crystallisation kinetics of fast-growth phase-change materials for mark-formation prediction

A basic understanding of the thermal and crystallisation processes involved in phase-change recording is required to accelerate research on development of high data rate and high-capacity formats, such as the digital video recording (DVR) system (T. Narahara et al, Jpn. J. Appl. Phys., vol. 39, no. 2B, pp. 912-919, 2000; M.J. Dekker et al, Proc. SPIE vol. 4090, pp. 28-35, 2000) and dual-layer DVR format. A simulation tool to predict formation and erasure of amorphous marks has proven to be helpful. Last year, we presented modelling results for mark formation and erasure in dual-layer DVR stacks based on fast-growth phase-change materials (E.R. Meinders et al, Proc. SPIE vol. 4342, pp. 64-75, 2001). One of the main challenges of such a simulation tool is accurate determination of the input parameters, such as the thermal properties of the disc and the crystallisation kinetics. We have developed the melt-threshold method to determine the thermal properties from threshold power measurements and modelling (E.R. Meinders et al, Jpn. J. Appl. Phys. vol. 40, pp. 1558-1564, 2001). In this paper, we present results of the experimentally determined crystallisation kinetics used in the mark formation and erasure model. We discuss modelling results and compare the predicted mark shapes with transmission electron microscopy (TEM) measurements.