Dual-work-function metal gates by full silicidation of poly-Si with Co-Ni bi-Layers

Author

Liu, J. ; Wen, H.-C. ; Lu, J.P. ; Kwong, D.-L.

Author_Institution

Dept. of Electr. & Comput. Eng., Univ. of Texas, Austin, TX, USA

Volume

26

Issue

4

fYear

2005

fDate

4/1/2005 12:00:00 AM

Firstpage

228

Lastpage

230

Abstract

Dual-work-function metal gates fabricated by full silicidation (FUSI) of Co-Ni bi-layer with doped poly-Si were investigated for the first time, along with single-metal FUSI systems of CoSi₂ and NiSi. Complete conversion of poly-Si into Co-Ni alloy silicided metal gate (FUSI) Co_xNi_1-xSi₂ was demonstrated. Although a linear relationship between work function and Ni percentage was observed for FUSI of undoped poly-Si systems, the work functions of doped Co_xNi_1-xSi₂ are almost identical to those of doped NiSi FUSI metal gates. The alloy FUSI metal gates explored in this letter provide a new class of metal gates for CMOS devices that combine the advantages of both NiSi and CoSi₂, i.e., proper work function tunability of NiSi and high thermal stability of CoSi₂.

Keywords

CMOS integrated circuits; bismuth; cobalt alloys; cobalt compounds; elemental semiconductors; integrated circuit metallisation; nickel alloys; silicon; work function; CMOS devices; Co-Ni Bi-layers; Co-Ni alloy silicided metal gate; CoNiBiSi; CoSi₂; NiSi FUSI metal gates; doped Co_xNi_1-xSi₂; doped poly-Si; dual-work-function metal gates; full silicidation; single-metal FUSI system; thermal stability; undoped poly-Si system; work function tunability; Capacitors; Cobalt alloys; Electrodes; Nickel alloys; Rapid thermal annealing; Silicidation; Silicides; Silicon alloys; Thermal resistance; Thermal stability; NiSi; dual work function; full silicidation (FUSI); metal gate;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2005.844696

Filename

1408025