6H-SiC single crystal implanted with N+ ions with an energy of 160keV and a dose of 1×1017cm−2 at room temperature was analyzed by atomic force microscopy (AFM), positron annihilation lifetime spectroscopy (PALS) and superconducting quantum interference device (SQUID). AFM analysis results show the morphological characteristics of degraded implanted sample. PALS analysis indicated the main defect type was silicon vacancy (VSi) and the concentration of VSi increased in the SiC after N ion implantation. SQUID results showed that N-implanted 6H-SiC sample exhibits room-temperature ferromagnetic (RTFM) behavior. It is demonstrated that room temperature ferromagnetism can be obtained by metal-free doping. The possible mechanism of ferromagnetic order was briefly discussed. ► The main defect type was silicon vacancy (VSi). ► The concentration of VSi increased in the SiC after N ion implantation. ► Clearly loop at 300K indicate FM ordering dominated the sample.