Crystallization of Ag-In-Sb-Te phase-change optical recording films

Crystalline phases formed on thermally annealed and laser-annealed Ag12.4In 3.8Sb55.2Te28.6 four-element alloy films were observed to be different. Aft er 1 h isothermal annealing at temperatures between 190 degreesC and 450 de greesC, hexagonal Sb and chalcopyrite AgInTe2 phases were observed, whereas laser annealing by initialization at laser power higher than 2.86 mW/mum(2 ) yielded cubic crystalline Sb and AgSbTe2 phases. There was only one exoth ermic peak at 170 degreesC determined by differential scanning calorimetry (DSC) measurement. Only the hexagonal Sb phase was observed by X-ray diffra ction of samples subjected to DSC measurement. These experimental results s uggest that the activation energy for crystallization derived from Kissinge r's equation using DSC data may not be the same as that for crystallization during erasing of phase-change optical recording disks.