Highly Reliable Multilevel and 2-bit/cell Operation of Wrapped Select Gate (WSG) SONOS Memory

Woei Cherng Wu, Tien-Sheng Chao, Wu Chin Peng, Wen Luh Yang, Jer Chyi Wang, Jian Hao Chen, Chao Sung Lai, Tsung Yu Yang, Chien Hsing Lee, Tsung Min Hsieh, Jhyy Cheng Liou

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14 Scopus citations


In this letter, high-performance and reliable wrapped select gate (WSG) polysilicon-oxide-nitride-oxide-silicon (SONOS) memory cells with multilevel and 2-bit/cell operation have been successfully demonstrated. The multilevel storage is easily obtained with fast program/erase speed (10 μs/5 ms) and low programming current (3.5 μA) for our WSG SONOS by a source-side injection. Besides the excellent reliability properties of our multilevel WSG-SONOS memory including unconsidered gate and drain disturbance, long charge retention (> 150 °C) and good endurance (> 104) are also presented. This novel WSG-SONOS memory with a multilevel and 2-bit/cell operation can be used in future high-density and high-performance memory application.

Original languageEnglish
Pages (from-to)214-216
Number of pages3
JournalIEEE Electron Device Letters
Issue number3
StatePublished - 7 Mar 2007


  • Multilevel operation
  • source-side injection
  • wrapped select gate (WSG) polysilicon-oxide-nitride-oxide-silicon (SONOS)


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