US Patent 7180848 Optical information recording medium

An optical information recording medium is composed of at least a phase-change type recording layer 4 provided on a substrate 1. The optical information recording medium is conducted to record and erase information by changing a phase of the phase-change type recording layer by irradiating light. The phase-change type recording layer is further composed of TiwGexSbyTez, wherein each of w, x, y and z is in atomic percent and satisfies following relations: 0.5≦w≦4.0, 3.4≦x≦14.5, 2.1≦y/z≦4.0 and w+x+y+z=100.