Application of simulation on the design of phase-change optical recording disks

Optical absorption and thermal conduction are the two key factors affecting temperature distribution and, subsequently, the write, erase characteristics of a phase-change optical recording disk, Therefore, by using carefully measured film physical properties of each layer, this work simulates a transient temperature profile while simultaneously considering optical absorption and thermal conduction, Through the simulated transient temperature profile, tooling-rate and reflectivity, dependence of phase-changed spot size on the laser power and laser pulse duration was observed, The proper combination of the disk structure and the associated write, erase conditions are obtained as well, A disk structure can subsequently be designed on the basis of this information, In addition, a novel dielectric layer, i.e. hydrogenated amorphous carbon (alpha-C:H), is simulated and compared with the disk applying conventionally used ZnS-SiO2 dielectric layers, The disk structures used herein are PC/ZnS-SiO2/GeSbTe/ZnS-SiO2/Al and PC/alpha-C:H/GeSbTe/alpha-C:H/Al. According to those results, a-C:H film is highly promising as a dielectric layer of the phase change optical recording disk for both wavelengths of 780 and 660 nm.