The charge generated in 6H-SiC n+p diodes by oxygen (O) ion irradiation at energies between 6 and 15 MeV was evaluated using the Transient Ion Beam Induced Current (TIBIC). The signal peak of the transient current increases, and the fall-time decreases with increasing applied reverse bias. The value of collected charge increases with increasing applied reverse bias, and the saturation of the collected charge was observed in high reverse bias regions (e.g. above 70 V in the case of 12MeV O-irradiation). The charge generated in the deeper region than the depletion layer is collected due to the "funneling effect". Almost all charge generated in n+p SiC diodes by O-irradiation between 6 and 15 MeV is collected when the length of the depletion layer becomes longer than the projection range of ions.