Journal of the Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회논문지)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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Evaluation of Multi-Level Memory Characteristics in Ge2Sb2Te5/TiN/W-Doped Ge2Sb2Te5 Cell Structure

Ge2Sb2Te5/TiN/W-Doped Ge2Sb2Te5 셀 구조의 다중준위 메모리 특성 평가

  • Jun-Hyeok Jo (School of Chemical Engineering, Chonnam National University) ;
  • Jun-Young Seo (School of Chemical Engineering, Chonnam National University) ;
  • Ju-Hee Lee (School of Chemical Engineering, Chonnam National University) ;
  • Ju-Yeong Park (School of Energy Resource Engineering, Chonnam National University) ;
  • Hyun-Yong Lee (School of Chemical Engineering, Chonnam National University)
  • 조준혁 (전남대학교 화학공학부) ;
  • 서준영 (전남대학교 화학공학부) ;
  • 이주희 (전남대학교 화학공학부) ;
  • 박주영 (전남대학교 에너지자원공학과) ;
  • 이현용 (전남대학교 화학공학부)
  • Received : 2023.10.10
  • Accepted : 2023.11.27
  • Published : 2024.01.01
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Abstract

To evaluate the possibility as a multi-level memory medium for the Ge2Sb2Te5/TiN/W-doped Ge2Sb2Te5 cell structure, the crystallization rate and stabilization characteristics according to voltage (V)- and current (I)- pulse sweeping were investigated. In the cell structures prepared by a magnetron sputtering system on a p-type Si (100) substrate, the Ge2Sb2Te5 and W-doped Ge2Sb2Te5 thin films were separated by a barrier metal, TiN, and the individual thicknesses were varied, but the total thickness was fixed at 200 nm. All cell structures exhibited relatively stable multi-level states of high-middle-low resistance (HR-MR-LR), which guarantee the reliability of the multilevel phase-change random access memory (PRAM). The amorphousto-multilevel crystallization rate was evaluated from a graph of resistance (R) vs. pulse duration (T) obtained by the nanoscaled pulse sweeping at a fixed applied voltage (12 V). For all structures, the phase-change rates of HR→MR and MR→LR were estimated to be approximately t<20 ns and t<40 ns, respectively, and the states were relatively stable. We believe that the doublestack structure of an appropriate Ge-Sb-Te film separated by barrier metal (TiN) can be optimized for high-speed and stable multilevel PRAM.

Keywords

Acknowledgement

이 논문은 전남대학교 연구비 지원에 의하여 연구되었음(과제번호: 2022-0128).

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