| 摘要 |
PROBLEM TO BE SOLVED: To form a dielectric layer at a high rate and to produce an optical recording medium at a low cost by using a sputtering target having a specified relative density or above in the formation of the dielectric layer by sputtering. SOLUTION: The sputtering target has >=98% relative density. The optical recording medium is a phase change type one. The dielectric layer is preferably a ZnS-SiO2 mixed film excellent in long-term preservability, in particular a ZnS-SiO2-carbon mixed film less liable to cause the deterioration of recording sensitivity, C/N, vanishing rate, etc. In order to ensure >=98% relative density by powder sintering, HIP(hot isostatic pressing) is preferably carried out at >=1,000 deg.C and >=100 MPa pressure. The typical layer structure of the optical recording medium is obtd. by successively laminating a 1st dielectric layer, a recording layer, a 2nd dielectric layer and a reflecting layer on a transparent substrate. The material of the reflecting layer is preferably a metal such as Al or Au or an alloy based on these. The material of the recording layer is preferably a Pb-Ge-Sb-Te alloy.
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