Effect of a Ge interlayer on the high-temperature behavior of NiSi films

The effect of a thin Ge interlayer on the formation of Ni silicides on (100)Si substrates has been investigated. X-ray diffraction shows a remarkable increase of the nucleation temperature of NiSi2 in the presence of the Ge interlayer. Four-probe measurements show that the sheet resistance of silicide formed in Ni/Ge/Si system remains stable up to 850 degreesC, while the sheet resistance of silicide formed in Ni/Si system presents a significant increase at 750 degreesC. Scanning electron microscopy indicates that island formation is not observed in the NiSi film grown on Ge/Si substrate annealing at 800 degreesC. The classical nucleation theory is employed to explain the increased temperature of the nucleation of NiSi2 in the Ni/Ge-Si system. (C) 2004 American Institute of Physics.