The effect of poly-Si thickness on silicidation of Ni film was investigated by using X-ray diffraction, auger electron spectroscopy, cross-sectional scanning transmission electron microscopy, resistivity, I-V, and CV measurements. The poly-Si films with various thickness of 30-200 nm were deposited by LPCVD on thermally grown 50 run thick SiO(2), followed by deposition of Ni film right after removing the native oxide. The Ni film was prepared by using atomic layer deposition with a N(2)-hydroxyhexafluoroisopropyl-N(1) (Bis-Ni) precursor. Rapid thermal process was then applied for a formation of fully silicide (FUSI) gate at temperature of 500 degrees C in N(2) ambient during 30 s. The resultant phase of Ni-silicide was strongly dependent on the thickness of poly-Si layer, Continuously changing its phase from Ni-rich (Ni(3)Si(2)) to Si-rich (NiSi(2)) with increasing the thickness of the poly-Si layer, which is believed to be responsible for the observed flat band voltage shift, Delta V(FB), in C-V curves. (C) 2009 Elsevier B.V. All rights reserved.