New buried channel flash memory cell with symmetrical source/drain structure

Hidekazu Oda, Shuichi Ueno, Natsuo Ajika, Masahide Inuishi, Hirokazu Miyoshi

Research output: Contribution to journalArticle

Abstract

In flash memory, the writing operation is achieved by channel hot electron injection and the erasing operation is achieved by Fowler-Nordheim tunneling. Therefore, high voltage must be applied in both operations. In memory cells, the source/drain structures are asymmetrical in order to efficiently carry out writing/erasing operations. However, the asymmetrical structures and high voltage operation are serious obstacles in designing devices with microscopic structures. In order to overcome these obstacles, a memory cell with buried channel nMOSFETs was fabricated. This device had a symmetrical source/drain structure in order to achieve efficient hot carrier injection and low voltage operation. In addition, the reliability of the tunnel oxide layer was improved by implanting nitrogen into the tunnel oxide layer.

Original languageEnglish
Pages (from-to)76-84
Number of pages9
JournalElectronics and Communications in Japan, Part II: Electronics (English translation of Denshi Tsushin Gakkai Ronbunshi)
Volume80
Issue number4
Publication statusPublished - 1997 Apr

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Keywords

  • Buried channel nMOSFET
  • Flash memory
  • Nitrogen implantation
  • Symmetrical structure

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Computer Networks and Communications
  • Electrical and Electronic Engineering

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