Interface properties of Hf-based high-k gate dielectrics —O vacancies and interface reaction—

Author

Shiraishi, Kenji

Author_Institution

Univ. of Tsukuba, Tsukuba

fYear

2007

fDate

16-20 Dec. 2007

Firstpage

37

Lastpage

41

Abstract

We have investigated, theoretically the cause of the substantial threshold voltage (V_th) shifts observed in Hf-related high-k gate stacks with p+poly-Si and p-metal gates, by focusing on the ionic nature of HfO₂. The oxygen vacancy (Vo) level in ionic HfO₂ is located in a relatively higher part of the band gap. This high position of the V_O results in a significant elevation of the Fermi level for p+poly-Si and p-metal gates, if Si can interact with high-k HfO₂. Vo formation in the HfO₂ induces a subsequent electron transfer from HfO₂ to gates, causing a substantial V_th shifts in MISFETs.

Keywords

Fermi level; MIS structures; MISFET; hafnium compounds; high-k dielectric thin films; Fermi level pinning; HfO₂; MISFET; high-k gate dielectric; interface property; interface reaction; oxygen vacancy; p+poly-Si gate; p-metal gate; substantial threshold voltage shift; Channel bank filters; Dielectric substrates; Electrons; Hafnium oxide; High K dielectric materials; High-K gate dielectrics; Large scale integration; Leakage current; MISFETs; Threshold voltage; Fermi level pinning; High-k HfO2 dielectrics; Oxygen vacancy; poly-Si and metal gates; send a blank e-mail to shiraishi@comas.frsc.tsukuba.ac.jp;

fLanguage

English

Publisher

ieee

Conference_Titel

Physics of Semiconductor Devices, 2007. IWPSD 2007. International Workshop on

Conference_Location

Mumbai

Print_ISBN

978-1-4244-1728-5

Electronic_ISBN

978-1-4244-1728-5

Type

conf

DOI

10.1109/IWPSD.2007.4472450

Filename

4472450