VDMOS器件二维数值模拟和典型参数优化分析

本文编制了功率MOSFET二维稳态分析软件TDSPM程序基于漂移扩散模型,特别考虑了功率器件高压工作状态下的速场特性和强场产生机制,因此可以对器件各工作区(包括击穿区)进行模拟。用全耦合法求解联立方程,用截断法修正迭代结果,大大改善了程序求解的收敛性和稳定性,使求解加压步长可取得很大(饱和区漏压可取100200V)。用TDSPM模拟VDMOS,得到器件的外部特性曲线和内部物理量分布;着重分析了击穿过程的内部机制;最后用TDSPM对器件进行了优化分析。

TWO-DIMENSIONAL NUMERICAL SIMULATION FOR VDMOS DEVICE AND THE OPTIMIZATION OF ITS TYPICAL PARAMETERS

A software for numerical simulation of power MOSFET, called TDSPM, is developed. In the program, DDM model is used. The velocity-electrical field characteristics and generation/recombination effect in high electrical field region for electrons are specially considered for simulating device performances at high voltage including the case of breakdown. The entirely coupled method is used. To enlarge the increment of applied voltage, the truncation method is employed. With the truncation method, the increment of drain-to-source of 100-200V can be used in saturation region. TDSPM is applied to simulation of VDMOS. The output characteristics are simulated. Internal distributions of some physical parameters are calculated and investigated. Special emphasis is placed on breakdown. At last the software is applied to optimization of VDMOS.