Growth-Dominant Superlattice-Like Medium and Its Application in Phase Change Memory

Abstract

Lateral PCM is one structure with good thermal confinement and low RESET current. Ideal growth-dominant (GD) phase change material is needed for lateral Phase change memory (PCM). We propose the concept of GD superlattice-like (SLL) phase change structure. GeTe and Sb7Te3 were selected to form the GD SLL structure. Crystallization temperature and resistivity of GeTe and Sb7Te3 were thickness dependent. The crystallization temperature of GeTe/Sb7Te3 SLL phase change structure increase with increasing thickness ratio of GeTe/Sb7Te3. GeTe/Sb7Te3 SLL structure built with a thickness ratio of 1.6:1 (GeTe to Sb7Te3) exhibited the lowest melting temperature compared to other thickness ratio. For a typical lateral PCM employing such GeTe/Sb7Te3 SLL phase change structure, stable SET/RESET operations with a low RESET current of 1.5 mA, SET and RESET speed of 30 nanoseconds, a good endurance above 106 cycles and a high RESET/SET resistance ratio window of 20 were achieved, demonstrating strong potentials in next generation non-volatile memory application.