We utilize spin-dependent recombination (SDR) to observe deep level trap defects at or very near the interface of 6H silicon carbide and the SiO2 gate dielectric in SiC metal-oxide-semiconductor field effect transistors. The SDR response is strongly correlated to SiC/SiO2 interface recombination currents. The magnitude of the SDR response is correlated with processing-induced changes in interface trap density, an extremely strong indication that we are observing the dominating interface/near interface trapping defects. The SDR response is extremely large, as large as one part in 350. © 2004 American Institute of Physics.