Effect of thin metal layers on the work function of polysilicon-metal electrode stacks

Husam Niman Alshareef*, H. C. Wen, K. Choi, R. Harris, P. Lysaght, H. Luan, P. Majhi, B. H. Lee

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

Abstract

The impact of thin metal nitride layers on the effective work function (EWF) of poly-Si/metal gate stacks has been investigated. The electrode stacks studied include very thin (0.5-2.0 run) TaNx and MoNx metal layers sandwiched between the poly-Si gate and the gate dielectric. Both n and p-type polysilicon electrodes were evaluated. The results indicate that when the metal nitride layers are as thin as 0.5 nm, they can have significant effect on the polysilicon effective work function. The observed results are explained by reactions between poly-Si and the metal nitrides leading to the formation of TaxSiyNz in the case of TaN x inter-layers. As the metal nitride inter-layers become thicker, the work function is controlled by the metal nitride EWF. Preliminary quasistatic C-V analysis shows minimal poly depletion with the metal inter-layers. Gate leakage current and fixed charges comparable to conventional polysilicon electrodes were obtained.

Original languageEnglish (US)
Pages198-206
Number of pages9
StatePublished - Dec 1 2005
Event207th ECS Meeting - Quebec, Canada
Duration: May 16 2005May 20 2005

Other

Other207th ECS Meeting
CountryCanada
CityQuebec
Period05/16/0505/20/05

ASJC Scopus subject areas

  • Engineering(all)

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