Phase-change optical recording medium

Abstract

A phase-change optical recording medium has a recording film that brings about reversible phase-change between a crystalline phase and an amorphous phase upon irradiation with light and an interface film formed in contact with at least one surface of the recording film and comprising hafnium (Hf), silicon (Si), oxygen (O) and carbon (C).

1 . A phase-change optical recording medium, comprising: 
 a recording film that brings about reversible phase-change between a crystalline phase and an amorphous phase upon irradiation with light; and    an interface film formed in contact with at least one surface of the recording film,    the interface film comprising:    at least one element selected from the group A consisting of titanium (Ti), niobium (Nb), zinc (Zn), praseodymium (Pr), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and ruthenium (Ru);    oxygen (O);    silicon (Si); and    at least one element selected from the group B consisting of carbon (C) and nitrogen (N).    
     
     
         2 . The phase-change optical recording medium according to  claim 1 , wherein the interface film has an extinction coefficient of 1×10 −4  or less.  
     
     
         3 . The phase-change optical recording medium according to  claim 1 , wherein the recording film is represented by the general formula:  
         Ge x Sb y Te z ,  where x+y+z=100, and wherein the recording film has a composition within a range defined by x=55, z=45; x=45, z=55; x=10, y=28, z=42; and x=10, y=36, z=54 on the ternary phase diagram of GeSbTe.    
     
     
         4 . The phase-change optical recording medium according to  claim 3 , wherein Bi and/or Sn is substituted for a part of the constituent elements of the recording film, and wherein the recording film has a composition represented by the general formula:  
         (Ge w Sb (1-w) ) x (Sb v Bi (1-v) ) y Te z ,  where x+y+z=100, 0≦w<0.5 and 0≦v<1.0.    
     
     
         5 . The phase-change optical recording medium according to  claim 1 , wherein the recording film is represented by the general formula:  
         Ge x Bi y Te z ,  where x+y+z=100, and wherein the recording film has a composition within a range defined by x=55, z=45; x=45, z=55; x=10, y=28, z=42; and x=10, y=36, z=54 on the ternary phase diagram of GeBiTe.