Effect of thin Si insertion at metal gate/high-k interface on electrical characteristics of MOS device with La2O3

D. Kitayama*, T. Koyanagi, K. Kakushima, P. Ahmet, K. Tsutsui, A. Nishiyama, N. Sugii, K. Natori, T. Hattori, H. Iwai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The effect of a thin Si layer insertion at W/La2O3 interface on the electrical characteristics of MOS capacitors and transistors is investigated. A suppression in the EOT increase can be obtained with Si insertion, indicating the inhibition of diffusion of oxygen atoms into La 2O3 layer by forming an amorphous La-silicate layer at the W/La2O3 interface. In addition, positive shifts in V fb and Vth caused by Si insertion implies the formation of amorphous La-silicate layer at the top of La2O3 dielectrics reduces the positive fixed charges induced by the metal electrode. Consequently, a large improvement in mobility has been confirmed for both at peak value and at high Eeff of 1 MV/cm with Si inserted nFETs. Although a degradation trend on EOT scaling has been observed, the insertion of thin Si layer is effective in pushing the scaling limit.

Original languageEnglish
Pages (from-to)1330-1333
Number of pages4
JournalMicroelectronic Engineering
Volume88
Issue number7
DOIs
StatePublished - Jul 2011

Keywords

  • Direct contact
  • Effective mobility
  • High-k
  • La-silicate

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