Crystallization behavior of as-deposited, melt-quenched, and primed amorphous states of Ge/sub 2/Sb/sub 2.3/Te/sub 5/ films in phase change optical recording

In phase change (PC) optical data storage, information is recorded as sub-micron sized amorphous marks (bits) on a moving polycrystalline chalcogenide film using a focused high power laser pulse. It raises the local temperature of the film above its melting temperature (T/sub M/) and the subsequent rapid cooling leaves an amorphous mark. These amorphous marks can be erased (i.e., re-crystallized) by locally annealing them above the glass transition temperature of the storage material under the same focused laser beam at a moderate power level. Here, we will discuss the crystallization behavior of the as-deposited, melt-quenched and primed Ge/sub 2/Sb/sub 2.3/Te/sub 5/ (GST) film used in data storage.