The semiconducting disilicide of the Fe-Si binary system β-FeSi 2 has been synthesized by the Ion Beam Synthesis (IBS) technique. High purity n-type float zone silicon wafers have been irradiated at various fluences from 5×1015 to 1×1017 by Fe 10+ beam at 90 keV using a ECR based low energy ion beam implanter. The irradiated samples were annealed in pure argon ambient at 900°C for 1 hour. GIXRD measurements were done at 0.5 degree incidence on the irradiated samples and the beta phase was identified. Raman measurements confirm the existence of β-FeSi2. In addition to the semiconducting β-FeSi2 phase, the sample irradiated with the highest dose contains the metallic alpha phase. The transition from beta to alpha phase observed in the sample that is annealed at relatively lower temperature has been assigned to the presence of lattice defects.