This work demonstrates a new approach for fabrication of high-quality oxide layers on 4H-SiC with application for gate-dielectrics for power electronic MOSFETs as well as for surface passivation in general. The exposure of 1016 cm-3 nitrogen-doped 4H-SiC substrates to a biased, pure oxygen plasma causes the formation of a 5 nm SiO2 layer on the substrate surface in very short times starting at 10 min at temperatures as low as 20°C. Continued by a 60 min thermal annealing step in low-pressure O2 atmosphere at 900°C, TEM investigations revealed the formation of a SiO2 layer of a total thickness of 14 nm. In comparison to the SiO2 growth rates of dry thermal oxidation of 4H-SiC the reported oxide layer thickness takes 60 min process time at 1150°C in a O2 atmosphere at atmospheric pressure.