beta-FeSi2 quantum dots (QD) were grown by evaporating 2, 4 and 7 nm Fe onto Si(100) wafers and in situ annealed at 600 degreesC for 10 min. QDs were grown also by reactive deposition epitaxy (RDE) evaporating 2 nm Fe onto a 600 degreesC Si substrate and annealed further for 5 min. MIS structures were prepared by evaporating SiOx over the QDs and A1 dots on the oxide. The SEM investigations show the density of the QDs is about 10(10) cm(-2) in the 2 and 4 nm Fe samples, and it increases to about 3 x 10(11) cm(-2) in the 7 nm Fe sample. The nanoscope investigation shows well resolved QDs only in the 7 nm Fe samples, but their density and size do not allow individual characterization of the QDs by scanning capacitance microscopic measurements. In the RDE samples the QDs are small and irregular, indicating the need for thicker Fe layer. Capacitance-voltage (C-V) measurements show point defects generated by silicidation which compensate the silicon doping (2 x 10(15) cm(-3)) in about 1 mum depth. C-V results show that in the RDE samples less point defect are generated, their concentration is lower than doping of the Si wafers. The electrical characteristics of MIS structures show that the room temperature deposited iron degrades the I-V characteristics, and induces leakage. (C) 2004 Elsevier B.V. All rights reserved.