Title :
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
fDate :
4/1/2005 12:00:00 AM
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) CoxNi1-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 CoxNi1-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 CoxNi1-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;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2005.844696
