Sb2Te3/TiTe2-Heterostructure-Based Phase Change Memory for Fast Set Speed and Low Reset Energy

The phase change memory (PCM) device has spotlighted as a candidate group for storage class memory devices and neuromorphic devices. However, the conventional GST-based PCM has problems of relatively slow set speed and high reset energy consumption. In this study, we fabricate an amorphous Sb2Te3/TiTe2 heterostructure using a sputtering process by inserting multiple TiTe2 nanolayers inside the Sb2Te3 layer. The fabricated amorphous Sb2Te3/TiTe2 heterostructure film is confirmed as a phase change material with excellent properties through temperature-dependent crystallinity change and resistance change analysis. Also, the Sb2Te3/TiTe2 heterostructure is integrated into a conventional T-shape phase change memory with a bottom electrode diameter of 200 nm to analyze electrical switching characteristics. The Sb2Te3/TiTe2 heterostructure-based PCM exhibited a faster set speed (approximate to 30 ns) than the conventional GST-based PCM, and the reset energy consumption is also reduced by more than 80% compared with the GST-based PCM. In addition, the resistance drift coefficient is also reduced to 1/10 to improve the resistance drift characteristics. This study confirmed the excellent characteristics of the Sb2Te3/TiTe2 heterostructure as a phase change material and as a next-generation PCM.