Accurate FEM base nMOS switch modelling technique for RF applications

This paper teaches the way full-wave modelling methodology that has been considered for nMOS switch in BiCMOS technology process. A method mixing both RC extraction based method, in combination with Electromagnetic 3D FEM simulations is presented. This method allows a physical full-wave extraction of the substrate taking into account both shallow and deep trenches isolation. Partitioning methodology which is really key in that case is described keeping in mind its compatibility with commercial automated design flows. To support theoretical investigations, 2-ports S-parameters measurements are compared with simulated data obtained from the proposed method. From available results, a good correlation is obtained on both input and return losses (amplitude + phase) over a wide frequency range (up to 10 GHz). Parameters such as Coff and Ron are also compared and FOM (Figure Of Merit) is also issued. Typically a difference less than 50 mdB is obtained for insertion losses.