The present disclosure concerns a method of forming an electronic power component inside and on top of a semiconductor substrate, comprising the following successive steps: a) forming of a peripheral groove in the semiconductor substrate on the side of a first surface of the semiconductor substrate; b) deposition of an oxygen-doped polysilicon layer, on top of and in contact with the bottom and the lateral walls of the peripheral groove and with the first surface of the semiconductor substrate; c) local deposition of a glass layer, on the oxygen-doped polysilicon layer, the glass layer extending in the peripheral groove and further extending over a portion of the first surface of the semiconductor substrate; and d) etching of the oxygen-doped polysilicon layer so that it extends on the first surface of the semiconductor substrate beyond the glass layer.