By taking into account the transistor parasitic lumped elements originated from the contact pads and the metal interconnections including the top-down connection, an enhanced de-embedding procedure for on-wafer G-band measurements has been developed and implemented. This method relies on a transistor access lumped element modelling, with a special care for the top-down connection, which prove to be the main contributor to the series parasitic effects. RF measurements on four test structures are sufficient to build the entire access model. The improved performance of such de-embedding technique is demonstrated, especially in the upper range of G-band, on the small-signal equivalent circuit extraction of advanced SiGe HBTs.
