Potentiality of the Ag–In–Sb–Te Phase Change Recording Material for High Density Erasable Optical Discs

The feasibility of using Ag–In–Sb–Te phase change material for high density of directly overwritable optical discs has been studied. A linear density of 0.34 µm/bit with a track pitch of 0.74 µm is confirmed to be achievable with a light source wavelength of 680 nm, with an objective lens NA of 0.60 and the criteria of data-to-data jitter of less than 14% of the channel bit length. The recording characteristics are also studied using an optical system with a 635 nm red laser diode in order to investigate the attainment of a linear density of 0.267 µm/bit which is equivalent to the DVD-ROM (read only memory) specification.