功率MOSFET抗SEB能力的二维数值模拟

Two-dimensional Numerical Simulation of SEB Survivability of Power MOSFET

在分析了单粒子烧毁(SEB)物理机制及相应仿真模型的基础上,研究了无缓冲层MOSFET准静态击穿特性曲线,明确了影响器件抗SEB能力的参数及决定因素。仿真研究了单缓冲层结构MOSFET,表明低掺杂缓冲层可提高器件负阻转折临界电流,高掺杂缓冲层可改善器件二次击穿电压,据此提出一种多缓冲层结构,通过优化掺杂浓度和厚度,使器件的抗SEB能力得到了显著提高。仿真结果显示,采用三缓冲层结构,二次击穿电压近似为无缓冲结构的3倍,负阻转折临界电流提高近30倍。

Based on the analysis of the physical mechanism of single event burnout（SEB） and the corresponding simula- tion model,the quasi-stationary breakdown characteristic of MOSFET without buffer is simulated first, and the parame- ters that influence the SEB survivabihty of MOSFETs are discussed.Then, single buffer layer MOSFETs are simulated. The simulation results show that low doping level buffer layer can improve the critical snap-back current, and high doping level buffer layer can improve the second breakdown vohage.Then a multi-buffer layer structure is proposed.By optimizing the doping level and thickness of buffer layers, the SEB abilitty of MOSFETs is signifieantly improved.Sim- ulation results show that the second breakdown voltage of three-buffer layer structure is approximately three times that of nonbuffer layer strueture, the critical snap-back current is nearly 30 times.