The iridium silicide-silicon Schottky barrier has been fabricated and the diffraction spectra of samples are analyzed. The formation process of iridium silicide and the relation between the process and square resistance of the film are discussed. Schottky barrier height and infrared absorptivity are measured and analyzed. The results show that the iridium silicide-silicon barrier is a new type of structure expected to be used in detecting infrared radiation extended to longer wavelengths.