A method for producing a micromechanical and/or nanomechanical device includes partial etching of at least one sacrificial layer arranged between a first layer and a substrate, forming at least one cavity in which is arranged at least one portion of the sacrificial layer in contact with the first layer and/or the substrate. The method also includes chemical transformation of at least one wall of the first layer and/or the substrate in the cavity, delimiting at least one stop in the first layer and/or the substrate at the level of the portion of the sacrificial layer. The portion of the sacrificial layer and the chemically transformed wall of the first layer and/or the substrate is also eliminated.