Metalorganic chemical vapor deposition of non-GST chalcogenide materials for phase change memory applications

Abstract

The feasibility of InSbTe (IST) chalcogenide new materials by metalorganic chemical vapor deposition (MOCVD) was demonstrated for PRAM applications. IST-MOCVD at a low temperature of 250 degrees C resulted in a favorable conformal deposition in the trench structure with a high aspect ratio. The IST films grown at 250 degrees C showed the highest resistance of approximately 10(8) Omega/sq, suggesting the amorphous phase of IST and the films grown at 300 degrees C include various crystalline phases of IST, In-Sb, and In-Te. MOCVD-IST films exhibited a step-coverage of about 95% in the trench structure with a 5 : 1 aspect ratio (a height of 500 nm and a diameter of 100 nm) and also showed reliable filling of the trench under appropriate deposition conditions. Phase switching between amorphous and crystalline states in the IST films grown on a trench structure at a high-aspect ratio (3.5 : 1) was demonstrated showing functional characteristics for applications in memory devices. The IST-based chalcogenide films used included various crystallized phases of In-Sb-Te, In-Sb and In-Te, which proved to be favorable for multilevel data storage.