This paper describes how to characterize the pad structure embedding silicon devices directly in terms of scattering parameters. The new procedure accounts for distributed effects associated with the structure itself (e.g. the so-called dangling source leg effect) and other coupling effects. The proposed approach is key to extending device characterization into the mm-wave range. The procedure makes use of standard structures typically available on silicon tiles without calling for measurements of additional structures. Further, it does not rely on an equivalent circuit of the structure for its characterization. The procedure is demonstrated by measurements of structures available on the Tower-Jazz semiconductor SBC13 SiGe BiCMOS process. Results acquired over the broad range of frequencies from 2 to 50GHz will be presented and discussed.