A method is provided for producing a semiconductor layer having at least two different thicknesses from a stack of the semiconductor on insulator type including at least one substrate on which an insulating layer and a first semiconductor layer are successively disposed, the method including etching the first layer so that said layer is continuous and includes at least one first region having a thickness less than that of at least one second region; oxidizing the first layer to form an electrically insulating oxide film on a surface thereof so that, in the first region, the oxide film extends as far as the insulating layer; partly removing the oxide film to bare the first layer outside the first region; forming a second semiconductor layer on the stack, to form, with the first layer, a third continuous semiconductor layer having a different thickness than that of the first and second regions.