Crystallization of Ge2Sb2Te5 phase-change optical disk media

In this paper, the crystallization behaviour of amorphous Ge2Sb2Te5 thin films is investigated using differential scanning calorimetry), x-ray diffraction and optical transmissivity measurements. It is indicated that only the amorphous phase to face-centred-cubic phase transformation occurs during laser annealing of the normal phase-change structure, which is a benefit for raising the phase-change optical disk's 'carrier-to-noise ratio (CNR). For amorphous Ge2Sb2Te5 thin films,, the crystallization temperature is about 200degreesC and the melting temperature is 546.87degreesC. The activation energy for the crystallization, E-a, is 2.25eV. The crystallization dynamics for Ge2Sb2Te5 thin films obeys the law of nucleation and growth reaction. The sputtered Ge2Sb2Te5 films were initialized by an initializer unit. The initialization conditions have a great effect on the reflectivity contrast of the Ge2Sb2Te5 phase-change optical disk.