Combined Electromagnetic and Drift Diffusion Models for Microwave Semiconductor Device

Abstract

In this work, we present a numerical model to solve the drift diffusion equations coupled with electromagnetic model, where all simulations codes are implemented using MATLAB code software. As first, we present a one-dimensional (1-D) PIN diode structure simulation achieved by solving the drift diffusion model (DDM). Backward Euler algorithm is used for the discretization of the proposed model. The aim is to accomplish time-domain integration. Also, finite dif- ferent method (FDM) is considered to achieve space-Domain mesh. We introduced an iterative scheme to solve the ob- tained matrix systems, which combines the Gummel’s iteration with an efficient direct numerical UMFPACK method. The obtained solutions of the proposed algorithm provide the time and space distribution of the unknown functions like electrostatic potential and carrier’s concentration for the PIN diode. As second case, the finite-difference time-domain (FDTD) technique is adopted to analyze the entire 3-D structure of the stripline circuit including the lumped element PIN diode. The microwave circuit is located in an unbounded medium, requiring absorbing boundaries to avoid non- physical reflections. Active device results were presented and show a good agreement with other reference. Electro- magnetic results are qualitatively in agreement with other results obtained using SILVACO-TCAD.