Phase change disk media having rapid cooling structure

Abstract

It is found that a rapid cooling structure is effective to improve overwrite characteristics of phase change type optical disk media. For a rapid cooling structure, thin A1N dielectric layer, 30 nm, with high thermal conductivity is suitable. The layer is adopted between the active layer and the reflective metal layer in quadrilayer disk structure. The cooling rate of the disk is calculated to be 12°C/nsec. This disk structure shows clear amorphous marks. A thin active layer disk structure using GeTe–Sb2Te3–Sb ,alloy of 20 nm has produced two million cycle stable bit error rate characteristics.1)And the erasability of the disk having a rapid cooling structure goes up more than 30 dB and shows rather wide plateau region of power dependency. © 1989 The Japan Society of Applied Physics.