Influence of oxygen transfer in Hf-based high-k dielectrics on flatband voltage shift

Toshihide Nabatame, Masayuki Kimura, Hiroyuki Yamada, Akihiko Ohi, Tomoji Ohishi, Toyohiro Chikyow

研究成果: Article査読

9 被引用数 (Scopus)


We investigated flatband voltage (Vfb) behavior for several Hf-based high-k dielectrics, including HfO 2, Mg-, and La-incorporated HfO 2, HfSiO x, and Mg-, La-, and N-incorporated HfSiO x, during the reduction (forming gas annealing: FGA) and oxidation annealing (ODA) processes. A negative Vfb shift appeared in all high-k dielectrics as the FGA temperature increased. In contrast, a positive Vfb shift was observed after the introduction of additional oxygen into the high-k layer during ODA. The oxygen diffusion coefficient (D) values of all samples were estimated using Fick's law. The results showed that the D value of the HfO 2 dielectric was five times as large as that of the HfSiO x dielectric in ODA at 400°C. Furthermore, the Mg-, La-, and N- incorporated high-k dielectrics exhibited a larger D value compared with the pure high-k dielectrics. These results strongly suggest that the ionicity of high-k dielectrics, which we attribute to a large positive Vfb shift, enhances oxygen diffusion in the high-k layer.

ジャーナルThin Solid Films
出版ステータスPublished - 2012 2月 1

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 表面および界面
  • 表面、皮膜および薄膜
  • 金属および合金
  • 材料化学


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