| 摘要 |
PURPOSE:To prevent the increase in noise, the decrease in the change rate of effective optical characteristics and the decrease in erasing ratio by changing the crystallization temp. of a phase change film which is a recording film in the thickness direction of the recording film. CONSTITUTION:The recording film 3 formed on a substrate 1 is constituted of plural elements and the compsn. ratios thereof are varied in the thickness direction of the recording film 3 so that the crystallization temp. of the recording film 3 is increased on the substrate 1 side. Namely, the film of the phase change type consisting of an SbSeBi system is formed by sputtering as the recording film 3 to provide a region 31 where the Bi concn. is low, a region 32 where the Bi concn. is middle and a region 33 where the Bi concn. is high. The increase in noise, the decrease in the change rate of the effective optical characteristics and the decrease in the erasing ratio are prevented in this way. |
