非正交网格上半导体漂移扩散模型的控制体有限元方法研究

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

  • 摘要: 本文将经典的Scharfetter–Gummel格式与矢量基函数结合,获得了一种在非正交网格上可以稳定、准确求解半导体漂移扩散方程的控制体有限元格式(CVFEM–SG)。仿真了包括四边形网格MOSFET转移特征曲线、六面体网格BJT晶体管的稳态Gummel特性曲线等算例。测试结果表明:该方法对于计算机辅助设计建模后的棱边非正交的四边形/六面体等大变形网格具有良好的稳定性和准确性。

     

    Abstract: 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.

     

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