Research on Control Volume Finite Element Method for Semiconductor Drift-diffusion Models on Non-orthogonal Grids

TCAD (Computer-Aided Design) software has become the most commonly used tool for numerical simulation of radiation effects at the device level. Currently, mainstream TCAD tools adopt the drift-diffusion model to describe the electrodynamic processes in semiconductor devices. However, the finite volume method used to solve the semiconductor drift-diffusion equations faces challenges such as low robustness and strong dependence on the mesh. This paper combines the classical Scharfetter-Gummel scheme with the vector basis function to obtain a control volume finite element method (CVFEM-SG) that can stably and accurately solve the semiconductor drift-diffusion equations on non-orthogonal grids. This method is applied to simulate examples including the transfer characteristic curves of quadrilateral mesh MOSEFT and the steady-state Gummel characteristic curves of hexahedral mesh BJT transistors. Test results show that the new method still maintains good stability and accuracy for large-deformation grids such as quadrilateral/hexahedral meshes with non-orthogonal edges after TCAD modeling.