METHOD OF PROVIDING A PHASE-CHANGE OPTICAL RECORDING MEDIUM, AND A PHASE-CHANGE OPTICAL RECORDING MEDIUM

摘要

A phase-change recording medium having a recording layer (4) made of a Ge-Sb-Te alloy, comprises an interface reflection control layer (3) provided on a laser beam incident side of the recording layer (4). The interface reflection control layer (3) has an extinction coefficient k and a refractive index n, simultaneously satisfying: k /= 0.22n + 0.14, k /= 0.88n - 0.19, and n /= 2.8. From the foregoings, it follows that the intensity ratio between the reflected wave from and the incident wave on the interface between the recording layer (4) and the interface reflection control layer (3) is led to a specified range. As a result, for the recording layer (4) the ratio (Ac/Aa) of the light absorption rate (Ac) in the crystalline state to the light absorption rate (Aa) in the amorphous state increases. Furthermore, the optical contrast also has a sufficiently high value. It is therefore possible to produce a high quality readout signal in recording by overwriting. Further, by providing a heat diffusion layer (7) between the interface reflection control layer (3) and the substrate (1), the mark edge recording at a high recording density can be performed with precision. IMAGE