The invention relates to a method of producing a semiconductor device, comprising the following steps consisting in: forming first, second and third semiconductor layers (1, 2, 3), whereby the first and second layers (1, 3) contain a smaller concentration of oxidizable species than the second layer (2); forming a mask (4) on the third layer (3); and oxidizing the second layer (2) with the diffusion of oxidizing species through the third layer (3).