Material characterization and application of eutectic SbTe based phase-change optical recording media

A brief review is described on the material characterization(structure, and crystallization and amorphization process) and application of the Ge(Sb70Te30)+Sb alloy. A mechanism to enable fast crystalline growth is discussed based on its single phase, hexagonal crystalline structure. A competitive process of amorphization and re-crystallization during re-solidification is discussed with a simple simulation model, where it is suggested that continuous crystalline growth from the boundary of molten area assures no resolution limit in the formation of amorphous mark edge. Two important concepts of "enhanced recrystallization" and "2T-period divided pulse strategy" are proposed to fully utilize this class of material. The enhanced recrystallization realizes precise amorphous mark size control, realizing high density multi-level recording. The 2T-period divided pulse strategy resolves a pre-mature amorphization issue due to an insufficient cooling period in the case of over 100MHz clock frequency for high speed recording. Finally, it is reported that 120Mbps digital video recording(DVR) and over 40GB multi-level recording on CD size single layer are feasible.