The formation of 3C-SiC on Insulator (SiCOI) using as tool wet oxidation is studied The wet oxidation is very anisotropic strongly depended on the defect density; at first a 35nm thick 3C-SiC film was deposited on Si substrate, then the film was annealed by flash lamps. After irradiation two zones can be distinguished, the upper, which exhibits a high defect density and the lower where the defect density was significantly reduced. The upper zone was wet oxidized and an oxide layer was formed on top of a good quality 3C-SiC film. In parallel a buried oxide layer was formed by oxidation of the Si-substrate through small channels, which were formed in the SiC during the wet oxidation. Through the oxidized channels the Si substrate is oxidized fast forming a continuous buried oxide layer realizing a 3C-SiC On Insulator structure..