Optical recording medium and process for producing the same, sputtering target, using process of optical recording medium, and optical recording apparatus

Abstract

To provide an optical recording medium and the like that is adapted to higher density and higher speed recording of 8 times or more than that of DVD (about 28 m/sec or more) and that exhibits superior repeating and reservation properties. An optical recording medium is provided that comprises a substrate, and a recording layer, wherein at least one of recording, reproducing, erasing, and rewriting of information is carried out by means of reversible phase changes at marks on the recording layer, the reversible phase changes at marks are induced between crystalline and amorphous states by laser irradiation, the length of the respective marks is 0.4 μm or less in the traveling direction of the laser irradiation, and the recording layer has a composition expressed by the formula: InSb, wherein α and β are atomic percent of the respective elements; 0.73≦β/(α+β)≦0.90, α+β=100, alternatively a composition expressed by the formula: MInSb, wherein M represents an element other than In and Sb or an element combination containing two or more elements other than In and Sb; α and β are atomic percent of the respective elements, γ is atomic percent of the element or sum of atomic percent of the respective elements; 0.73≦β/(α+β)≦0.90, 0<γ<α, α+β+γ=100.