Systematical investigation and physical mechanism of HfO2 gate stacks band alignment, VFB shift and Fermi level pinning

Author

Wang, Xia L. ; Wang, W.W. ; Han, Kwangseok ; Zhang, Juyong ; Xiang, J.J. ; Ma, X.L. ; Yang, Hongming ; Chen, D.P. ; Ye, T.C.

Author_Institution

Key Lab. of Microelectron. Devices & Integrated Technol., Inst. of Microelectron., Beijing, China

fYear

2012

fDate

23-25 April 2012

Firstpage

1

Lastpage

2

Abstract

Band alignment of TiN/HfO₂/SiO₂/Si stack is systematically investigated by X-ray photoelectron spectroscopy. The differences of Si 2p binding energies between SiO₂ and Si substrate are experimentally found to decrease with the sequence of SiO₂/Si, 4 nm HfO₂/SiO₂/Si and 2 nm HfO₂/SiO₂/Si stacks. The p-type Schottky barrier heights at TiN/HfO₂ interface of TiN/HfO₂/SiO₂/Si stack are experimentally estimated to increase with thicker HfO₂ thickness. A physical model based on band alignment of TiN/HfO₂/SiO₂/Si stack is employed to successfully explain these experimental results. The positive VFB shift of TiN/HfO₂/SiO₂/Si stack and Fermi level pinning are also physically demonstrated by this model and attributed to interface induced gap states at TiN/HfO₂ and HfO₂/SiO₂ interfaces.

Keywords

Fermi level; Schottky barriers; binding energy; hafnium compounds; silicon compounds; titanium compounds; Fermi level pinning; HfO₂ gate stacks band alignment; HfO₂-SiO₂-Si; Si 2p binding energy; TiN-HfO₂; TiN-HfO₂-SiO₂-Si; V_FB shift; X-ray photoelectron spectroscopy; interface induced gap state; p-type Schottky barrier height; Hafnium oxide; Logic gates; Silicon; Tin;

fLanguage

English

Publisher

ieee

Conference_Titel

VLSI Technology, Systems, and Applications (VLSI-TSA), 2012 International Symposium on

Conference_Location

Hsinchu

ISSN

1930-8868

Print_ISBN

978-1-4577-2083-3

Type

conf

DOI

10.1109/VLSI-TSA.2012.6210159

Filename

6210159