Patent ID: 7371448

Claim:
An optical recording medium for high density phase change optical recording, said medium comprising gallium (Ga), antimony (Sb) and tellurium (Te) and unavoidable impurities, and having the following composition which is within the regions bounded by the broken lines in FIG. 2 : (Sb x Te 100-x ) 1-z (Ga y Sb 100-y ) z 35≦x≦55; 40≦y≦50; 0.05≦z≦0.9 said medium having: (1) single hexagonal phase after crystallization with lattice constant a ranging from 4.25 to 4.32 Å, c ranging from 11.200 Å to 11.657 Å, c/a ratio 2.58 to 2.72; (2) high grain growth rate in crystallization; (3) optimal activation energy of crystallization 3.0 to 6.3 eV; and (4) greater than 30 dB in writing CNR, and greater than 20 dB in erasure CNR.