Fermi pinning-induced thermal instability of metal-gate work functions

Author

Yu, H.Y. ; Ren, Chi ; Yeo, Yee-Chia ; Kang, J.F. ; Wang, X.P. ; Ma, H.H.H. ; Li, Ming-Fu ; Chan, D.S.H. ; Kwong, D.-L.

Author_Institution

Dept. of Electr. & Comput. Eng., Nat. Univ. of Singapore, Singapore

Volume

25

Issue

5

fYear

2004

fDate

5/1/2004 12:00:00 AM

Firstpage

337

Lastpage

339

Abstract

The dependence of the metal-gate work function on the annealing temperature is experimentally studied. We observe increased Fermi-level pinning of the metal-gate work function with increased annealing temperature. This effect is more significant for SiO₂ than for HfO₂ gate dielectric. A metal-dielectric interface model that takes the role of extrinsic states into account is proposed to explain the work function thermal instability. This letter provides new understanding on work function control for metal-gate transistors and on metal-dielectric interfaces.

Keywords

Fermi surface; annealing; dielectric properties; metal-insulator boundaries; silicon compounds; thermal stability; Fermi pinning-induced thermal instability; HfO₂; annealing temperature; extrinsic states; gate dielectric; metal gate transistors; metal gate work functions; metal-dielectric interface model; thermal stability; work function control; Annealing; Capacitors; Dielectric materials; Electrodes; Fabrication; Hafnium oxide; Inorganic materials; Laboratories; Silicon; Temperature dependence;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2004.827643

Filename

1295126