Method for producing a semiconductor device, comprising: producing a stack including a first crystalline semiconductor portion intended to form a channel and arranged on at least one second portion which can be selectively etched vis-à-vis the first portion, producing a dummy gate and external spacers, etching the stack, a remaining part of the stack under the dummy gate and the external spacers being conserved, producing source/drain by epitaxy from the remaining part of the stack; removing the dummy gate and the second portion, oxidizing portions of the source/drain from the parts of the source/drain revealed by the removal of the second portion, forming internal spacers, producing a gate electrically insulated from the source/drain by the external and internal spacers.