Nanocrystalline Al 2 O 3 layers were produced by means of impulse plasma deposition (IPD) technique on Si and SiC substrates. Morphology, microstructure and chemical composition of films and film/substrate interfaces were investigated using SEM and SIMS methods. After depositing on top of the layers metal (Al) dot contacts also C-V and I-V measurements of so produced metal-insulator-semiconductor structures were performed in order to determine their electrophysical properties. Obtained Al 2 O 3 films are uniform, show good adhesion to the substrates and maintain at the same time good stoichiometry and purity. Their electronic properties seem to be promising from the point of view of applications in microelectronics. Features, like low-leakage currents, high resistivity and reproducible C-V and I-V characteristics indicate that IPD aluminum oxide films may be a prospective dielectric material, especially for application in novel wide bandgap materials-based (e.g. SiC) electronic devices.