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Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
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The Analysis of Retention Characteristic according to Remnant Polarization(Pr) and Saturated Polarization(Ps) in 3D NAND Flash Memory

3D NAND Flash Memory의 Remnant Polarization(Pr)과 Saturated Polarization(Ps)에 따른 Retention 특성 분석

  • Lee, Jaewoo (Dept. of Electronics Engineering, Korea National University of Transportation) ;
  • Kang, Myounggon (Dept. of Electronics Engineering, Korea National University of Transportation)
  • Received : 2022.04.25
  • Accepted : 2022.06.23
  • Published : 2022.06.30
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Abstract

In this paper, retention characteristics of lateral charge migration according to parameters of 3D NAND flash memory to which ferroelectric (HfO2) structure is applied and ∆Vth were analyzed. The larger the Ps, the greater maximum polarization possible in ferroelectric during Programming. Therefore, the initial Vth increases by about 1.04V difference at Ps 70µC/cm2 than at Ps 25µC/cm2. Also, electrons trapped after the Program operation causes lateral charge migration over time. Since ferroelectric maintains polarization without applying voltage to the gate after Programming, regardless of Ps value, polarization increases as Pr increases and the ∆Vth due to lateral charge migration becomes smaller by about 1.54V difference at Pr 50µC/cm2 than Pr 5µC/cm2.

본 논문에서는 ferroelectric(HfO2)구조가 적용된 3D NAND flash memory의 parameter에 따른 lateral charge migration의 retention과 Vth를 분석하였다. Ps가 클수록 Program 시 ferroelectric에서 가능한 최대 polarization이 크기 때문에 초기 Vth는 Ps 25µC/cm2 보다 Ps 70µC/cm2에서 약 1.04V차이로 커진다. 또한 Program 이후 trap된 전자는 시간이 지남에 따라서 lateral charge migration이 발생한다. Program 이후 gate에 전압을 가하지 않고 ferroelectric은 polarization을 유지하기 때문에 Ps와 크게 관계없이 Pr이 클수록 polarization이 커지고 lateral charge migration에 의한 ∆Vth는 Pr 5µC/cm2 보다 Pr 50µC/cm2에서 약 1.54V차이로 작아진다.

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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