The Schottky barrier heights of the nickel silicide Schottky contacts formed at different annealing temperatures were independently investigated by I-V-T measurement and the infrared photocurrent measurement. It has been found that the Gaussian distribution of Schottky barrier height can be used to explain the experimental results very well. The Schottky barrier heights of the samples annealed at temperatures of 550 degreesC and 600 degreesC are larger than those of the samples annealed at the other temperatures. This may result from the phase transformation of nickel silicide at different annealing temperatures. The formation NiSi phase can be confirmed by Raman spectroscopy. (C) 2004 Elsevier B.V. All rights reserved.