Recording of 0.1 micron minimum mark size in a new phase change media

The shapes of phase-change marks on surface recording discs with a Substrate/Ag/lower ZnS-SiO2/AgInSbTe /upper ZnS-SiO2 layered structure were investigated by scanning electron microscopy (SEM). When the upper ZnS-SiO2 layer was removed by a wet chemical process, the marks were clearly observed as dark contrast in the secondary-electron image (SEI) mode. The SEM observation showed that the mark size could be reduced to around 0.1 mum in the tangential direction. The mark shapes were crescents, and fluctuation with scaling down was hardly visible. Uniform 0.1 mum marks made on surface recording discs which use AgInSbTe will allow an increase in disc capacity.