轨道交通用大功率IGBT结电容退化规律

Degradation Law of Junction Capacitance of High-Power IGBT for Rail Transit

结电容作为绝缘栅双极型晶体管(IGBT)芯片重要寄生参数之一,与器件开关动态性能密切相关。通过建立IGBT开关动态数学模型,搭建基于IGBT器件级行为模型的双脉冲测试仿真电路,研究了器件内部结电容对IGBT动态性能的影响规律和机理。进一步地,对机车不同服役时间的IGBT样本的结电容进行测试分析,验证了仿真模型的有效性。结果表明,IGBT结电容随服役时间增长均出现一定程度退化,其中栅极-发射极电容退化最为显著,进而导致IGBT开关损耗增大。这可能与长时间复杂应力耦合作用造成的栅氧退化、湿气侵入甚至材料特性变化有关。在工程应用中,结电容退化性能检测可为器件品质评估、状态监测及可靠性分析工作提供参考。

The junction capacitance,as one of the most important parasitic parameters of insulated gate bipolar transistor(IGBT)chips,is closely related to the switching dynamic performance of the device.By establishing the switching dynamic mathematical model of IGBT,the double pulse test simulation circuit based on the device level behavior model of IGBT was established.The influence law and mechanism of junction capacitance in the device on IGBT dynamic performance were studied.Then,the junction capacitance of IGBT samples selected from locomotives for different service time were tested and analyzed to verify the effectiveness of the simulation model.The results show that the junction capacitance of IGBT degrades with the increase of service time,especially the capacitance degradation between gate and emitter is of the most significant,which leads to the increase of IGBT switching loss.It is probably caused by the gate-oxide degradation,moisture intrusion and even the change of material characteristics under the influence of long-term complex stress coupling.The detection of junction capacitance degradation performance can provide reference for the quality evaluation,status monitoring and reliability analysis of devices in engineering applications.