R&D: Anomalous Crystallization Kinetics of Ultrafast ScSbTe Phase-Change Memory Materials Induced by Nitrogen Doping

Acta Materialia has published an article written by Bin Che, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518071, China, and Shenzhen Key Laboratory of New Information Display and Storage Materials, Shenzhen University, Shenzhen 518071, China, Yuanling Che, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518071, China, Yimin Chen, Department of Microelectronic Science and Engineering, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China, and Laboratory of Infrared Material and Devices & Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province, Advanced Technology Research Institute, Ningbo University, Ningbo 315211, China, Keyuan Ding, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518071, China, and Shenzhen Key Laboratory of New Information Display and Storage Materials, Shenzhen University, Shenzhen 518071, China, Dongqi Wang, Vnuo Certification&Testing Co. Ltd., Suqian 223802, China, Tao Song, Jiaen Huang, Feng Rao, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518071, China, and Shenzhen Key Laboratory of New Information Display and Storage Materials, Shenzhen University, Shenzhen 518071, China.

Abstract: “Phase-change random access memory has been served as a bridge across the memory wall within the conventional von Neumann computing architecture, owing to its excellent non-volatility and rapid switching. Nitrogen doping in Ge₂Sb₂Te₅-like phase-change materials (PCMs) was a routine method for enhancing non-volatility of amorphous phases, although sacrificing crystallization speed markedly. Here we introduced N element into Sc_0.3Sb₂Te₃ PCM that possesses sub-nanosecond crystallization speed, trying to cope with stability/reliability issues raised by backend thermal-budget processing. However, we observed an abnormal deterioration in thermal stability of N-doped amorphous Sc_0.3Sb₂Te₃ films. As compared to the undoped counterparts, they exhibit a weakened fragile-to-strong crossover in viscosity that gives rise to a higher atomic mobility at elevated temperatures while a less rigid vitreous network at low temperatures. Therefore, N doping leads to an accelerated crystal growth rate and a higher steady-state nucleation rate in heterogeneous manner, causing a faster crystallization, whereas the kinetic suffocation contributed by original Sc element as approaching room temperature must have been partially counteracted by N dopant. This acceleration in crystallization kinetics delivers N-doped Sc_0.3Sb₂Te₃ as a promising candidate in working memory.“