Abstract: In an information recording medium, a Bi—Ge—Te material is adopted as a phase-change recording layer material. A C—Ta—O material is used for at least any one of first and second boundary layers which are in contact with a recording layer.

Abstract: In an information recording medium, a Bi—Ge—Te material is adopted as a phase-change recording layer material. A C—Ta—O material is used for at least any one of first and second boundary layers which are in contact with a recording layer.

Abstract: In an optical disk for high density recording, for preventing the deformation of recording tracks caused by stress which may develop between the substrate and the recording stacked film formed thereon, a stress-compensation layer having a metal element such as Ti or Cr as a main component is provided. The stress-compensation layer undergoes contraction (tensile stress) to compensate for compression stress which develops in the stacked film during cooling after the thermal expansion of the substrate surface that occurs at the end of film formation. The stress-compensation layer has a pillar-like structure which, starting from the lower face, reaches the upper face of the film.

Abstract: A high-density information recording medium free from lowering the reflectance by over-write of a large number of times and exfoliation defect in a structure for suppressing cross-erase. This medium includes, over a substrate having a groove shape, a recording layer, and three-layered thin films of a first interference layer, a second interference layer and an interface layer having mutually different compositions and disposed on a laser beam incidence side of the recording layer in order named from the laser beam incidence side. The first interference layer has a smaller refractive index and a larger thermal conductivity than the second interference layer, the interface layer is interposed between the second interference layer and the recording layer, and a distance between the first interference layer and the recording layer is greater than at least a groove depth.

Abstract: In an optical disk for high density recording as DVD-RAM, for preventing the deformation of recording tracks caused by stress which may develop between the substrate and the recording stacked film formed thereon, a stress-compensation layer which comprises a metal element as Ti or Cr as the main component and has a property to undergo contraction (tensile stress) is provided, thereby to compensate the compression stress which develops in the stacked film owing to contraction of substrate surface during cooling after the thermal expansion of the substrate surface which occurs at the time of film formation and. To impart the property to contract to the layer, the layer is made to have a pillar-like structure which, starting from the lower face, reaches the upper face of the film.

Abstract: A high-density information recording medium free from lowering the reflectance by over-write of a large number of times and exfoliation defect in a structure for suppressing cross-erase. This medium includes, over a substrate having a groove shape, a recording layer, and three-layered thin films of a first interference layer, a second interference layer and an interface layer having mutually different compositions and disposed on a laser beam incidence side of the recording layer in order named from the laser beam incidence side. The first interference layer has a smaller refractive index and a larger thermal conductivity than the second interference layer, the interface layer is interposed between the second interference layer and the recording layer, and a distance between the first interference layer and the recording layer is greater than at least a groove depth.