Erbium silicide formation and its contact properties on Si(100) have been studied in this work. With sputtering and rapid thermal annealing, the deposited Er was found to react with the Si(100) substrate upon 300 degrees C annealing. The formed ErSi2-x is stable up to 1000 degrees C annealing. Problems of surface oxidation and defect formation were discussed. Pinhole or pyramidal defect was observed to form in the ErSi2-x films depending on the initial Er thickness. The electrical characteristics of ErSi2-x/p-Si(100) Schottky contacts were measured at room temperature for the annealing temperature ranging from 500 to 900 degrees C and Schottky barrier height (SBH) was found to vary between 0.783 and 0.805 eV. ErSi2-x/n-Si(100) contacts formed after annealing at a temperature from 500 to 900 degrees C, which have much lower SBHs, were characterized by temperature-dependent current-voltage measurement. The measurement results were analyzed with a Gaussian distribution model of the inhomogeneous SBH. The mean SBHs were extracted to be 0.343-0.427 eV for different annealing temperatures. The standard deviation of the SBH was found to be larger for the ErSi2-x/n-Si(100) diodes annealed at 700, 800, and 900 degrees C than for those annealed at 500 and 600 degrees C. (c) 2008 American Vacuum Society.