Crystallization behavior of as-deposited, melt quenched, and primed amorphous states of Ge₂Sb_2.3Te₅ films

We compare the crystallization behavior of thin films of Ge₂Sb_2.3Te₅ in various amorphous states, namely, as-deposited, melt-quenched, and primed. These films are embedded in a quadrilayer stack similar in structure to the commercially available phase-change optical disks. This study shows that the melt-quenched amorphous film has a shorter crystallization onset time and a higher crystallization rate in comparison to the as-deposited amorphous film. We also observed that variable priming leads to crystallization behavior falling between that of the as-deposited and melt-quenched states. A qualitative model of the modification in crystallization behavior due to priming is given based on the notion that priming produces crystalline embryos which hastens crystallization process.