Method of making a semiconductor layer having at least two different thicknesses

A method for producing a semiconductor layer having at least two different thicknesses (TSi1, TSi2) from a stack of the semiconductor on insulator type comprising at least one substrate on which an insulating layer and a first semiconductor layer are successively disposed, the method comprising at least a sequence comprising the following steps:

• etching of the first semiconductor layer so that the first semiconductor layer is continuous and comprises at least one first region the thickness (tsi1) of which is less than the thickness (tSi2) of at least one second region;
• oxidation of the first semiconductor layer in order to form an electrically insulating oxide film on the surface of the first semiconductor layer so that, in the first region, the oxide film extends as far as the insulating layer and so that in the second region the oxide film does not extend as far as the insulating layer;
• partial removal of the oxide film so as to bare the first semiconductor layer outside the first region and to keep at least part of the oxide film in the first region;
• formation on the stack of layers of a second semiconductor layer so as to form, with the first semiconductor layer, a third continuous semiconductor layer having different thicknesses (TSi1, TSi2).