Zero interface dipole induced threshold voltage shift of HfO 2/SiO2 gate dielectric stacks with NH3 plasma treatment

Jer Chyi Wang*, Chia Hsin Chen, Hsiang Yu Liu, Chih Ting Lin, Hsin Chun Lu

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

Abstract

The NH3 plasma treatment on interfacial SiO2 has been proposed to reduce the interface dipole effect of HfO2/SiO 2 gate dielectric stacks. The X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV-VIS) were used to establish the band diagram of the HfO2 films. The tetragonal crystallization phase of the HfO2 films examined by X-ray diffraction (XRD) was responsible for the band-gap increase during the NH3 plasma treatment. By using the Schottky emission and Fowler-Nordheim (F-N) tunneling, the effective electron barrier height of the Al/HfO2 gate stacks can be determined. Thus, the interface dipole and Fermi-level pinning induced flat-band voltage shifts of the Al/HfO2/SiO2/p-Si structure subjected to different NH3 plasma treatment conditions were obtained. It was found that the NH3 plasma treatment for about 4 min was sufficient for achieving the zero dipole interface of the HfO2/SiO2 gate dielectric stack due to the negligible movement of the oxygen ions between the HfO2 and the nitrided oxide.

Original languageEnglish
Pages (from-to)120-122
Number of pages3
JournalMicroelectronic Engineering
Volume109
DOIs
StatePublished - 2013

Keywords

  • Fermi-level pinning
  • HfO
  • High-k
  • Interface dipole
  • NH plasma

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