Origin of flat band voltage shift in HfO2 gate dielectric with La2O3 insertion

K. Kakushima, K. Okamoto, M. Adachi, K. Tachi, P. Ahmet, K. Tsutsui, N. Sugii, T. Hattori, H. Iwai

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

The origin of flat band voltage (VFB) shift with La2O3 insertion for HfO2 gate dielectrics has been carefully examined. By separating the effect of the fixed charges located at each interface by thickness-dependent VFB evolution, total voltage shifts (dipole) at metal/high-k and high-k/SiO2 interfaces have been estimated. Using stacked capacitors of La2O3 and HfO2, it can be concluded that VFB is mainly determined by the high-k on SiO2. Therefore, the dipole at La2O3 and the interface has an additional dipole of 0.36 eV compared with that of HfO2/SiO2. The same trend has also been obtained with a high-k on a Si substrate without a SiO2 layer. A simple model using electronegativity has been proposed to explain the VFB shift.

Original languageEnglish
Pages (from-to)1280-1284
Number of pages5
JournalSolid-State Electronics
Volume52
Issue number9
DOIs
Publication statusPublished - 2008 Sep
Externally publishedYes

Keywords

  • Electronegativity
  • Flat band voltage
  • HfO
  • High-k
  • LaO
  • Metal gate

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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    Kakushima, K., Okamoto, K., Adachi, M., Tachi, K., Ahmet, P., Tsutsui, K., Sugii, N., Hattori, T., & Iwai, H. (2008). Origin of flat band voltage shift in HfO2 gate dielectric with La2O3 insertion. Solid-State Electronics, 52(9), 1280-1284. https://doi.org/10.1016/j.sse.2008.04.015