Patent ID: 7569417

Claim:
A method of fabricating a phase changeable material layer usable in a semiconductor memory device, the method comprising: forming a plasma in a chamber having a substrate disposed therein; applying a first source gas of a germanium based material to deposit a layer of the germanium based material on the substrate while maintaining the plasma in the chamber; applying a second source gas of a tellurium based material to react with the layer of the germanium based material to form a germanium-tellurium composite material on the substrate while maintaining the plasma in the chamber; applying a third source gas of an antimony based material to deposit a layer of the antimony based material on the germanium-tellurium composite material while maintaining the plasma in the chamber; and applying a fourth source gas of tellurium based material to react with the layer of antimony based material to form an antimony-tellurium composite material on the germanium-tellurium composite material.