Phase change optical recording medium and process for manufacturing same

A phase change optical recording medium in which writing, reading and/or erasing of information is conducted by utilizing a change of phase of a recording layer by irradiation with light, said recording medium comprising a substrate, a first transparent dielectric layer on a substrate, a recording layer on the first transparent dielectric layer, a second transparent dielectric layer on the recording layer, and a reflective layer on the second transparent dielectric layer,

• wherein said first transparent dielectric layer in contact with said recording layer contains oxygen in a molar ratio greater than a molar ratio of oxygen in said second transparent dielectric layer and
• wherein said first and second transparent dielectric layers comprise ZnS added with 12 to 35 mol % of SiOx.

A process for manufacturing a phase change optical recording medium in which writing, reading and/or erasing of information is conducted by utilizing change of phase of a recording layer by irradiation with light, said process comprising the steps of preparing a substrate, forming a first transparent dielectric layer on the substrate, forming a recording layer on the first transparent dielectric layer, forming a second transparent dielectric layer on the recording layer, and forming a reflective layer on the second transparent dielectric layer,

• wherein said process further comprises a step of forming a third transparent dielectric layer between said first transparent dielectric layer and said recording layer, said first and second transparent dielectric layer being formed by sputtering in a rare gas atmosphere and said third transparent dielectric layers being formed by sputtering in an atmosphere comprising a gaseous mixture of a rare gas and at least one oxygen atom-containing gas, said third transparent dielectric layer having a thickness of 1 to 10 mn.

A process for manufacturing a phase change optical recording medium in which writing, reading and/or erasing of information is conducted by utilizing change of phase of a recording layer by irradiation with light, said process comprising the steps of preparing a substrate, forming a first transparent dielectric layer on the substrate, forming a recording layer on the first transparent dielectric layer, forming a second transparent dielectric layer on the recording layer, and forming a reflective layer on the second transparent dielectric layer,

• wherein said first and second transparent dielectric layers comprise ZnS added with 12 to 35 mol % of SiOx, and
• wherein said first transparent dielectric layer is formed by sputtering in an atmosphere comprising a gaseous mixture of a rare gas and at least one oxygen atom-containing gas, and said second transparent dielectric layer is formed by sputtering in a rare gas atmosphere.