Patent ID: 7393574
Filing Date: 2008-07-01
Classification: G11B,Y10T

Abstract:
1. An information recording medium in which information is recorded and played back by applying light, the information recording medium comprising: recording layer made of phase-change material and provided on a substrate; a first boundary layer provided in contact with the surface of the recording layer, the surface being on a side where the light is incident; and a second boundary layer provided in contact with the opposite surface of the recording layer from the side where the light is incident, wherein the recording layer contains bismuth (Bi), germanium (Ge), and tellurium (Te), wherein the recording layer is made of the phase-change material having a composition ratio in a range surrounded by the following four points (A1, A2, B1, and B2) represented by coordinates on a composition triangle having the bismuth (Bi), the germanium (Ge), and the tellurium (Te) at the vertices thereof: A1 (Bi3, Ge46.2, Te50.8) A2 (Bi5, Ge46, Te49) B1 (Bi13, Ge38, Te49) B2 (Bi10, Ge38, Te52) where coordinates on the composition triangle are expressed in atomic percent, at least one of the first and second boundary layers contains chromium (Cr), tantalum (Ta), and oxygen (O) and has a film thickness of 0.8 nm to 8 nm, and wherein at least one of the first and second boundary layers contains the chromium (Cr) and the tantalum (Ta) in a range in which a composition ratio (y/x) of a content (y) of the tantalum (Ta) to a content (x) of the chromium (Cr) is 0.05 to 0.7(0.05<(y/x)<0.7).