Method of forming a phase changeable material layer, a method of manufacturing a phase changeable memory unit, and a method of manufacturing a phase changeable semiconductor memory device

Abstract

A phase changeable material layer usable in a semiconductor memory device and a method of forming the same are disclosed. The method includes forming a plasma in a chamber having a substrate disposed therein, providing a first source gas including a germanium based material to form a first layer including the germanium based material on the substrate while maintaining the plasma in the chamber, providing a second source gas including a tellurium based material to react with the first layer to form a first composite material layer including a germanium-tellurium composite material on the substrate while maintaining the plasma in the chamber, providing a third source gas including an antimony based material to form a second layer including the antimony based material on the first composite material layer while maintaining the plasma in the chamber, and providing a fourth source gas including tellurium based material to react with the second layer including antimony based material to form a second composite material layer including an antimony-tellurium composite material on the first composite material layer. Accordingly, the phase changeable material layer may be formed at a low temperature and power to have desirable electrical characteristics.