Electrical measurements (DLTS, I-V and C-V) were combined with Auger Electron Spectroscopy (AES) to study the relation between the formation conditions of silicides and Schottky barrier heights. The mechanism of the barrier height depending on the distribution of defects/impurities produced during annealing, and the best annealing condition to form the ideal Schottky barrier of Pt silicides/Si are discussed in the present paper in detail.