A process for producing a component comprising a structure of III-V material(s) on the surface of a substrate, said structure comprising at least one upper contact level (N sup) defined on the surface of a first III-V material, which extends laterally above said substrate, and a lower contact level (N inf) defined on the surface of a second III-V material, which extends laterally above said substrate, involving: - encapsulating said structure with at least one dielectric; - producing, in said dielectric, at least one primary upper aperture (O sp) on the surface of said first III-V material and at least one primary lower aperture (O ip) on the surface of said second III-V material, so as to define contact bottom zones on said first III-V material and on said second III-V material; - producing contact bottom metallisations in said at least one upper aperture (Os) and in said at least one lower aperture (Oi), to form an intermediate structure; - encapsulating the intermediate structure with at least one dielectric of said at least one primary upper aperture (O sp) and of said at least one primary lower aperture (O ip); - producing at least one secondary upper aperture (O ss) in the dielectric located in said at least one primary upper aperture (O sp), and producing at least one secondary lower aperture (O is) in the dielectric located in said primary lower aperture (O ip); - filling said at least one secondary upper aperture (O ss) and said at least one secondary lower aperture (O is) with at least one metallic material so as to produce at least one upper contact pad on a lower contact bottom metallisation surface that is smaller than the surface of the contact bottom metallisation deposited in said at least one primary upper aperture and at least one lower contact pad on a lower contact bottom metallisation surface that is smaller than the surface of the contact bottom metallisation deposited in said at least one primary lower aperture; - the contact bottom metallisations and the contact pads defining at least one upper contact of said first III-V material in contact with said upper contact level (N sup) and at least one lower contact of said second III-V material in contact with said lower contact level (N inf); - at least said upper contact and at least said lower contact are integrated in dielectric and have an upper surface which is not covered by the dielectric and defined in one and the same plane; - the contact bottom metallisations being of a different nature than that of the metallic material; - said structure having a lower base made of second III-V material and a mesa made of first III-V material located above said base. - encapsulating said structure with at least one dielectric; - producing, in said dielectric, at least one primary upper aperture (O sp) on the surface of said first III-V material and at least one primary lower aperture (O ip) on the surface of said second III-V material, so as to define contact bottom zones on said first III-V material and on said second III-V material; - producing contact bottom metallisations in said at least one upper aperture (Os) and in said at least one lower aperture (Oi), to form an intermediate structure; - encapsulating the intermediate structure with at least one dielectric of said at least one primary upper aperture (O sp) and of said at least one primary lower aperture (O ip); - producing at least one secondary upper aperture (O ss) in the dielectric located in said at least one primary upper aperture (O sp), and producing at least one secondary lower aperture (O is) in the dielectric located in said primary lower aperture (O ip); - filling said at least one secondary upper aperture (O ss) and said at least one secondary lower aperture (O is) with at least one metallic material so as to produce at least one upper contact pad on a lower contact bottom metallisation surface that is smaller than the surface of the contact bottom metallisation deposited in said at least one primary upper aperture and at least one lower contact pad on a lower contact bottom metallisation surface that is smaller than the surface of the contact bottom metallisation deposited in said at least one primary lower aperture; - the contact bottom metallisations and the contact pads defining at least one upper contact of said first III-V material in contact with said upper contact level (N sup) and at least one lower contact of said second III-V material in contact with said lower contact level (N inf); - at least said upper contact and at least said lower contact are integrated in dielectric and have an upper surface which is not covered by the dielectric and defined in one and the same plane; - the contact bottom metallisations being of a different nature than that of the metallic material; - said structure having a lower base made of second III-V material and a mesa made of first III-V material located above said base.