This work reports on the growth and characterization of Al 2 O 3 films on 4H-SiC, by Plasma Enhanced-Atomic Layer Deposition (PE-ALD). Different techniques were used to investigate the morphological, structural and electrical features of the Al 2 O 3 films, both with and without the presence of a thin SiO 2 layer, thermally grown on the 4H-SiC before ALD. Capacitance-voltage measurements on MOS structures resulted in a higher dielectric constant (ε~ 8.4) for the Al 2 O 3/SiO 2/SiC stack, with respect to that of the Al 2 O 3/SiC sample (ε~ 6.7). Moreover, Current density-Electric Field measurements demonstrated a reduction of the leakage current and an improvement of the breakdown behaviour in the presence of the interfacial thermally grown SiO 2. Basing on these preliminary results, possible applications of ALD-Al 2 O 3 as gate insulator in 4H-SiC MOSFETs can be envisaged.