We report on improved SiCOI (SiC On Insulator) structures elaborated on new Unibond material. Using conventional high temperature deposition technique to grow 3C-SiC, only small cavities (similar to100 to 250 rim diameter) were found in the buried layers. They cover less than 0.03% of the overall interface, with average density similar to10(5) cm(-2). This is by far the lowest value ever reported but the density is still several orders of magnitude too high to be related to the defect density in the starting material. The deposited SiC layers have state of the art properties and the new point is that the layers grown on the thinner SOI structure exhibit the best overall quality.