Production of a transistor, the channel structure of which comprises at least one finned channel structure, the method comprising: forming, from a substrate (1), a molding block (3), forming, on the molding block, a thin layer (7) made from a given semiconductor or semi-metallic material, and consisting of one to ten atomic or molecular monolayers of two-dimensional crystal, withdrawing the molding block while retaining a portion (7a) of the thin layer extending against a lateral face of the molding block, said retained portion (7a) forming a fin that is capable of forming a channel structure of the transistor, producing a coating gate electrode against said fin.