Understanding the Effects of Ta Doping in Sb2Te3 for High-Performance Phase Change Memory

초록

Phase change memory is a leading candidate for storage class memory (SCM). Among various phase-change materials, Sb-Te-based materials, which have high-speed operation characteristics, are actively studied. Herein, a high-performance phase-change material is designed for doping tantalum (Ta) inside Sb2Te3 (ST). To optimize the Ta doping concentration, Ta-doped ST films with various Ta concentrations are fabricated using a sputtering process. The phase change characteristics of the fabricated Ta-doped ST films of various concentrations are analyzed, and the crystallographic, structural, and electrical effects of Ta doping inside Sb2Te3 are analyzed. Analysis of the Ta doping effect on Sb2Te3 shows that the crystallization temperature of the ST-based phase-change material increased and that grain growth is suppressed, thereby affecting electrical conductivity. Consequently, the optimized Ta doping concentration as a phase-change material is obtained. A phase change memory device is fabricated using optimized Ta(0.41):ST and confirmed to have fast set speed (approximate to 15 ns) and low resistance drift characteristics. Through this study, the Ta doping effect of Sb2Te3 is extensively analyzed, and the optimal Ta doping concentration is demonstrated. It is confirmed that Ta-doped ST is a high-performance phase-change material applicable to next-generation SCM.

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