Theoretical investigation of the interfaces between Hf-based high-k dielectrics and poly-Si and metal gates

K. Shiraishi, T. Nakayama, Y. Akasaka, S. Miyazaki, T. Nakaoka, K. Ohmori, P. Ahmet, K. Torii, H. Watanabe, T. Chikyow, Y. Nara, K. Yamada

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have theoretically investigated poly-Si and metal gates on Hf-related high-k gate dielectrics. First, we have investigated the cause of the Fermi level pinning (FLP) in Hf-related high-k gate stacks with p+poly-Si gates. The oxygen vacancy (Vo) level in ionic HfO 2 is located in a relatively higher part of the band gap. If the p+poly-Si-gate is in contact with HfO 2, Vo formation in the HfO 2 induces a subsequent electron transfer across the interface because of the higher energy level position of Vo, causing FLP in p+poly-Si gate MISFETs. Next, we investigate the unusual behaviors of metal effective work functions (WFs) on Hf-related high-k gate stacks. We have constructed a a new concept of generalized charge neutrality level. Our theory systematically reproduces the experimentally observed effective WFs of various gate materials, and will become a useful guiding principle for material selection of gate metals.

Original languageEnglish
Title of host publicationProceedings of the 5th International Conference on Semiconductor Technology, ISTC 2006
Pages320-329
Number of pages10
Publication statusPublished - 2006
Event5th International Conference on Semiconductor Technology, ISTC 2006 - Shanghai, China
Duration: 2006 Mar 212006 Mar 23

Publication series

NameProceedings - Electrochemical Society
VolumePV 2006-03

Other

Other5th International Conference on Semiconductor Technology, ISTC 2006
CountryChina
CityShanghai
Period06/3/2106/3/23

ASJC Scopus subject areas

  • Engineering(all)

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    Shiraishi, K., Nakayama, T., Akasaka, Y., Miyazaki, S., Nakaoka, T., Ohmori, K., Ahmet, P., Torii, K., Watanabe, H., Chikyow, T., Nara, Y., & Yamada, K. (2006). Theoretical investigation of the interfaces between Hf-based high-k dielectrics and poly-Si and metal gates. In Proceedings of the 5th International Conference on Semiconductor Technology, ISTC 2006 (pp. 320-329). (Proceedings - Electrochemical Society; Vol. PV 2006-03).