In this paper, some aspects of the electrical characterization of trapping phenomena occurring at interfaces between insulators and wide band semiconductors (WBG) are presented, with a focus on the SiO 2/SiC and SiO 2/GaN systems. In particular, time resolved capacitance, current measurements, and parallel conductance measurements as a function of frequency were correlated to investigate trapping states in SiC and GaN MOS-structures, allowing to distinguish between slow and fast states in these systems. Furthermore, gate ...