A method for manufacturing a SeOI substrate that includes a thin working layer made from one or more semiconductor material(s); a support layer; and a thin buried oxide layer between the working layer and the support layer. The method includes a manufacturing step of an intermediate SeOI substrate having a buried oxide layer with a thickness greater than a thickness desired for the thin buried oxide layer; and a dissolution step of the buried oxide layer in order to form therewith the thin buried oxide layer. After the dissolution step, an oxidation step of the substrate is conducted for creating an oxidized layer on the substrate, and an oxide migration step for diffusing at least a part of the oxide layer through the working layer in order to increase the electrical interface quality of the substrate and decrease its Dit value.