A method of production of a field-effect transistor from a stack of layers forming a semiconductor-on-insulator type substrate, the stack including a superficial layer of an initial thickness, made of a crystalline semiconductor material and covered with a protective layer, the method including: defining, by photolithography, a gate pattern in the protective layer; etching the gate pattern into the superficial layer to leave a thickness of the layer of semiconductor material in place, the thickness defining a height of a conduction channel of the field-effect transistor; forming a gate in the gate pattern; forming, in the superficial layer and on either side of the gate, source and drain zones, while preserving, in the zones, the initial thickness of the superficial layer.