Electromagnetic and Semiconductor Modeling of Scanning Microwave Microscopy Setups

This article presents finite difference time domain (FDTD) and finite element method (FEM) based electromagnetic modeling and simulation of an industrial scanning microwave microscopy (SMM) material measurement setup. These two methods have been employed to cross verify each other for classical electromagnetic simulations of the homogeneous conductive materials under SMM. For the SMM simulations involving semiconductor materials, however, a coupled multiphysics solver is required in addition to the pure electromagnetic analysis. As a solution to this problem, an FEM-based semiconductor Poisson-Drift-Diffusion (PDD) solver and its coupling to transient electromagnetic solver is presented in this article. The considered SMM setup consists of a conductive fine tip suspended at a certain height above the sample. For the validation purposes of electromagnetic solvers, the numerical modeling was based on both the time domain FEM (TD-FEM) and FDTD. Both numerical methods extract the scattering parameters from the computed field of the conductive or dielectric samples. At the second stage of the analysis, the TD-FEM solver is coupled with the time domain PDD semiconductor solver in order to simulate charge transport and explain behavior of the charges in semiconducting domains under electromagnetic illumination similar to SMM setups.