Self-assembled β-FeSi2 quantum (QD) dots were grown on n-type Si and investigated in this work. Secondary electron images show the shape and distribution of the quantum dots depends on the temperature and thickness of the Fe deposition. Electrical characteristics were measured in MIS devices prepared by covering the quantum dots by an oxide or by a photoresist layer. The cold deposited and subsequently annealed Fe layers were found to generate large concentration of deep level defects, compensating the upper few microns layer of the silicon wafer. Reactive deposition epitaxy (RDE) growth of QDs – where the iron is deposited on hot substrate—generated much lower concentration of defect, in some devices with characteristics comparable to the reference wafer. The significant scatter on the surface is attributed to inhomogeneous growth conditions and to residual surface contamination on the surface.