Equivalent circuit fitting method for microwave characterisation of low-k dielectric thin films

Abstract An equivalent fitting analysis scheme is proposed for extending a method developed for high-k dielectrics to correctly characterise low-k dielectrics, which are more sensitive to various parasitics. The same concentric capacitor devices and measurement setup are used as in the original method, as they are easy to fabricate, which made the old approach attractive in the first place. The physical model used in the analysis step of the original method, which overestimates the dielectric permittivity, is improved by implementing fringing fields and a parasitic gap capacitance as a circuit element. The new approach is verified on experimental data and is demonstrated to more accurately determine the dielectric permittivity compared to the original method.