Energy-band model offsets, trap density distributions and gate leakage characteristics of MOS capacitors with PECVD and thermal gate oxides on 3C- and 4H-SiC were compared. The difference in trap energy distributions between the polytypes demonstrated in this experiment confirms that the 3C-SiC polytype is less vulnerable to near-interface traps (NIT) which are found in high density in the 4H-SiC. It was also shown that the examined 3C-SiC substrates demonstrated higher leakage currents due to higher dislocation concentration compared with 4H-SiC. Finally, the energy band model of the SiC MOS devices was described quantitatively which could be considered in further development of the devices and processes.