Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
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A Study of the Memory Characteristics of Al2O3/Y2O3/SiO2 Multi-Stacked Films with Different Tunnel Oxide Thicknesses

터널 산화막 두께에 따른 Al2O3/Y2O3/SiO2 다층막의 메모리 특성 연구

  • Jung, Hye Young (Department of Materials Science and Engineering, Yonsei University) ;
  • Choi, Yoo Youl (Department of Materials Science and Engineering, Yonsei University) ;
  • Kim, Hyung Keun (Department of Materials Science and Engineering, Yonsei University) ;
  • Choi, Doo Jin (Department of Materials Science and Engineering, Yonsei University)
  • Received : 2012.05.04
  • Accepted : 2012.08.22
  • Published : 2012.11.30
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Abstract

Conventional SONOS (poly-silicon/oxide/nitride/oxide/silicon) type memory is associated with a retention issue due to the continuous demand for scaled-down devices. In this study, $Al_2O_3/Y_2O_3/SiO_2$ (AYO) multilayer structures using a high-k $Y_2O_3$ film as a charge-trapping layer were fabricated for nonvolatile memory applications. This work focused on improving the retention properties using a $Y_2O_3$ layer with different tunnel oxide thickness ranging from 3 nm to 5 nm created by metal organic chemical vapor deposition (MOCVD). The electrical properties and reliabilities of each specimen were evaluated. The results showed that the $Y_2O_3$ with 4 nm $SiO_2$ tunnel oxide layer had the largest memory window of 1.29 V. In addition, all specimens exhibited stable endurance characteristics (program/erasecycles up to $10^4$) due to the superior charge-trapping characteristics of $Y_2O_3$. We expect that these high-k $Y_2O_3$ films can be candidates to replace $Si_3N_4$ films as the charge-trapping layer in SONOS-type flash memory devices.

Keywords

References

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