Data storage device having a phase change memory medium reversible by direct overwrite

Claim 2

In an optical data storage memory device comprising a substrate, a dielectric first encapsulating layer on the substrate, a memory layer on the dielectric first encapsulating layer, and a dielectric second encapsulating layer atop the memory layer, the improvement wherein the memory layer is a non-ablative, reversible, phase change memory layer comprising a solid solution of antimony, selenium, and tellurium, said solid solution being single phase in the amorphous and crystalline states, having a crystallization temperature above 120 degrees Centigrade, and having the composition (Sb.sub.2 Te.sub.3).sub.1-x (Sb.sub.2 Se.sub.3).sub.x where x is from 0.18 to 0.43.

Claim 3

In an optical data storage memory device comprising a substrate, a dielectric first encapsulating layer on the substrate, a memory layer on the dielectric first encapsulating layer, and a dielectric second encapsulating layer atop the memory layer, the improvement wherein: (a) the memory layer has a nominal thickness of 800 Angstroms, is a non-ablative, reversible, phase change memory layer comprising a solid solution of antimony, selenium, and tellurium, said solid solution being single phase in the amorphous and crystalline states, having a crystallization temperature above 120 degrees Centigrade, and having the composition; (Sb.sub.2 Te.sub.3).sub.1-x (Sb.sub.2 Se.sub.3).sub.x where x is from 0.20 to 0.35; (b) the dielectric first encapsulating layer has a nominal thickness of 1030 Angstroms and comprises germanium oxide; (c) the dielectric second encapsulating layer has a nominal thickness of 2060 Angstroms and comprises germanium oxide; and (d) the memory device has a crystallization time of less then 300 nanoseconds at 8300 Angstrom incident laser radiation.

Claim 4

In an optical data storage memory device comprising a substrate, a dielectric first encapsulating layer on the substrate, a memory layer on the dielectric first encapsulating layer, and a dielectric second encapsulating layer atop the memory layer, the improvement wherein: (a) the memory layer has a nominal thickness of 800 Angstroms, is a non-ablative, reversible, phase change memory layer comprising a solid solution of antimony, selenium, and tellurium, said solid solution being single phase in the amorphous and crystalline states, having a crystallization temperature above 120 degrees Centigrade, and having the composition; (Sb.sub.2 Te.sub.3).sub.1-x (Sb.sub.2 Se.sub.3).sub.x where x is from 0.20 to 0.35; (b) the dielectric first encapsulating layer has a nominal thickness of 1030 Angstroms and comprises germanium oxide; (c) the dielectric second encapsulating layer has a nominal thickness of 2060 Angstroms and comprises germanium oxide; and (d) the memory device has a crystallization time of less then 300 nanoseconds at 8300 Angstrom incident laser radiation.