Silicon Carbide based electronics remains the most suitable choice to replace silicon in power electronics. Especially in avionics SiC devices represent a reliable solution for reducing weight and size of aircraft power switching technology. However, some issues need to be solved to unleash the full potential of this kind of electronics. The most important challenge is related to the quality of the dielectric/SiC interface and to the techniques implemented to fabricate this interface. In this work, we investigate the morphological and electrical properties of low temperature dielectric films deposited on SiC substrate by using ECR-PECVD. To this end, we fabricated capacitors with silicon dioxide layer, deposited at low temperature, studying their performance with and without surface pretreatments and considering post-annealing effects at different temperatures and times.