Experimental study of three-dimensional fin-channel charge trapping flash memories with titanium nitride and polycrystalline silicon gates

Yongxun Liu, Takashi Matsukawa, Kazuhiko Endo, Shinichi O'uchi, Junichi Tsukada, Hiromi Yamauchi, Yuki Ishikawa, Wataru Mizubayashi, Yukinori Morita, Shinji Migita, Hiroyuki Ota, Meishoku Masahara

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Three-dimensional (3D) fin-channel charge trapping (CT) flash memories with different gate materials of physical-vapor-deposited (PVD) titanium nitride (TiN) and n+-polycrystalline silicon (poly-Si) have successfully been fabricated by using (100)-oriented silicon-on-insulator (SOI) wafers and orientation-dependent wet etching. Electrical characteristics of the fabricated flash memories including statistical threshold voltage (Vt) variability, endurance, and data retention have been comparatively investigated. It was experimentally found that a larger memory window and a deeper erase are obtained in PVD-TiN-gated metal-oxide-nitride-oxide-silicon (MONOS)-type flash memories than in poly-Si-gated poly-Si-oxide- nitride-oxide-silicon (SONOS)-type memories. The larger memory window and deeper erase of MONOS-type flash memories are contributed by the higher work function of the PVD-TiN metal gate than of the n+-poly-Si gate, which is effective for suppressing electron back tunneling during erase operation. It was also found that the initial Vt roll-off due to the short-channel effect (SCE) is directly related to the memory window roll-off when the gate length (Lg) is scaled down to 46 nm or less.

Original languageEnglish
Article number04ED16
JournalJapanese journal of applied physics
Volume53
Issue number4 SPEC. ISSUE
DOIs
Publication statusPublished - 2014 Apr
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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