Suppression of fermi level pinning and flat band voltage shift by inserting diamond-like carbon at a high-k/SiO2 interface in a gate stack structure

Yuta Iwashita, Tetsuya Adachi, Kenji Itaka, Atsushi Ogura, Toyohiro Chikyow

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1 Citation (Scopus)

Abstract

Fermi level pinning (FLP) has been a major impediment to limiting flat band voltage (Vfb) shift in the metal/high-k gate stacks. This phenomenon occurs due to dipole formation at the high-k/SiO2 interface, caused by oxygen diffusion from the high-k oxide to the underlying SiO2. One method of eliminating FLP is to suppress oxygen diffusion through the high-k/SiO 2 interface. Diamond-like carbon (DLC) has potential as an oxygen diffusion barrier, since it has an appropriate optical band gap and dielectric constant. After inserting DLC into a high-k/SiO2 interface, we found that FLP was suppressed, since we observed a less flat band shift before and after rapid thermal annealing in an oxygen atmosphere. We could also see a clear work function dependence, giving direct evidence of FLP elimination when using Pt and W in an HfO2/DLC/SiO2 gate stack.

Original languageEnglish
Pages (from-to)06GH031-06GH034
JournalJapanese journal of applied physics
Volume49
Issue number6 PART 2
DOIs
Publication statusPublished - 2010 Jun 1
Externally publishedYes

ASJC Scopus subject areas

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

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