A method of manufacturing a fixed structure defining a volume receiving a movable member including a mems

The invention relates to the manufacture of a fixed structure (20) of semiconductor defining a volume (10), for example of a MEMS microelectromechanical system (1). The method comprises: pre-determining (E100) Ei thicknesses depending on functional distances (b, p, c) associated with elements (30, 32, 34), forming (E210, E220, E230) of at least one element on a substrate (21), said formation (E210, E220, E230) comprising a thermal oxidation (E214, E224, E234) of the substrate (21) for forming a layer (23, 26, 27) of thickness E1 oxide, followed by selective etching (E216, E226, E236) of the layer (23, 26, 27) of oxide to define said volume (10) in an engraved portion (25) by exposure of the substrate under -jacent and to define the element in a non-etched portion (24) and subsequent oxidation (E240) of the substrate to form a layer (28) of thickness E4 oxide, so as to obtain the elements having said functional distances .