PHASE-CHANGE OPTICAL RECORDING MEDIUM

摘要

A phase-change optical recording medium such that the reflectance circumferential distribution after initial crystallization is uniform, the recording capacity is equivalent to that of DVD-ROMs, overwrite recording at ten-fold recording linear velocity (35 m/s), and adequate modulation degree is possible. (1) On a substrate, a first intermediate layer, a recording layer, a second intermediate layer, and a reflective layer are formed in this order. The recoding layer is made of an alloy having a composition expressed by GaalphaSnbetaIngammaSbdelta (where alpha, beta, gamma, and delta are numbers in atom%, 5<=alpha<=20, 2<=beta<=20, 2<=gamma<=20, 40<=delta<=80, and alpha+beta+gamma+delta=100). Data can be recorded on this phase-change optical recording medium or erased from this medium by using reversible phase change between the amorphous and crystalline phases of the recording layer.