PHASE CHANGE TYPE INFORMATION RECORDING MEDIUM AND SPUTTERING TARGET

摘要

PROBLEM TO BE SOLVED: To provide a phase change type information recording medium in which initial crystallization is easy, recording sensitivity is excellent at a high line speed with the same capacity as that of for DVD-ROM and with the recording line speed of ten times or more, overwrite recording can be executed, and which has excellent storage reliability.

SOLUTION: At least a first protective layer, a phase change recording layer, a second protective layer, and a reflective layer are formed on a transparent substrate in this order in the phase change type information recording medium. The recording of the information is executed by the reversible phase changes of a crystalline state and a noncrystalline state of the phase change recording layer by the irradiation with a laser beam. The alloy, which is the main component of a material constituting the phase change recording layer, has the composition formulas of SnαSbβGaγGeδ[wherein α, β, γ, and δ satisfy α+β+γ+δ=100 and represent a composition ratio (atom%) of each element], and 5≤α≤25, 40≤β≤91, 2≤γ≤20, and 2≤δ≤20 are satisfied.

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