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Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
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The Analysis of Lateral Charge Migration at 3D-NAND Flash Memory by Tapering and Ferroelectric Polarization

Tapering과 Ferroelectric Polarization에 의한 3D NAND Flash Memory의 Lateral Charge Migration 분석

  • Lee, Jaewoo (Dept. of Electronics Engineering, Korea National University of Transportation) ;
  • Lee, Jongwon (Dept. of Electronics Engineering, Korea National University of Transportation) ;
  • Kang, Myounggon (Dept. of Electronics Engineering, Korea National University of Transportation)
  • Received : 2021.11.19
  • Accepted : 2021.12.29
  • Published : 2021.12.31
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Abstract

In this paper, the retention characteristics of 3D NAND flash memory applied with tapering and ferroelectric (HfO2) structure were analyzed after programming operation. Electrons trapped in nitride are affected by lateral charge migration over time. It was confirmed that more lateral charge migration occurred in the channel thickened by tapering of the trapped electrons. In addition, the Oxide-Nitride-Ferroelectric (ONF) structure has better lateral charge migration due to polarization, so the change in threshold voltage (Vth) is reduced compared to the Oxide-Nitride-Oxide (ONO) structure.

본 논문에서는 tapering과 ferroelectric(HfO2)구조가 적용된 3D NAND flash memory의 프로그램 이후 시간경과에 따른 retention특징을 분석했다. Nitride에 trap된 전자는 시간이 지남에 따라 lateral charge migration이 발생한다. 프로그램 이후 시간이 지남에 따라 trap된 전자가 tapering에 의해 두꺼워진 채널 쪽으로 lateral charge migration이 더 많이 발생하는 것을 확인했다. 또한 Oxide-Nitride-Ferroelectric (ONF) 구조는 polarization에 의해 lateral charge migration이 완화되기 때문에 기존 Oxide-Nitride-Oxide (ONO) 구조 보다 문턱전압(Vth)의 변화량이 줄어든다.

Keywords

Acknowledgement

This work was supported in part by the Institute of Information and Communications Technology Planning and Evaluation (IITP) funded by the Korea government (MSIT) under Grant 2021-0-01764 and in part by the MOTIE(Ministry of Trade, Industry & Energy (10085645) and KSRC(Korea Semiconductor Research Consortium) support program for the development of the future semiconductor device and in part by Korea Institute for Advancement of Technology (KIAT) grant funded by the Korea Government (MOTIE) (N000P0008500, The Competency Development Program for Industry Specialist).

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