Dependence of Short-Circuit Withstand Capability of SiC MOSFETs on Short-Circuit Failure Time
Dependence of Short-Circuit Withstand Capability of SiC MOSFETs on Short-Circuit Failure Time
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DOI：
10.1109/tpel.2021.3073991
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发表时间：
2021-04
影响因子：
6.7
通讯作者：
T. Shoji;M. Kuwahara;M. Usui
中科院分区：
文献类型：
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作者：
T. Shoji;M. Kuwahara;M. Usui
本文的目的是阐明SiC金属氧化物半导体场效应晶体管的短路故障机制，导致邻近栅极的层间介质的机械故障，找到短路耐受能力和短路故障时间之间的关系，并根据短路故障时间分类故障模式。当短路失效时间短于临界时间时，由SiC管芯的热膨胀引起的作用在层间电介质上的应力超过氧化物膜的断裂应力极限。因此，在栅极和源极之间的层间电介质处出现裂纹。在这种情况下，由于SiC管芯的热膨胀由温度上升决定，因此可以通过热理论预测耐短路能力。然而，当短路失效时间长于临界时间时，作用在层间电介质上的应力小于氧化膜的断裂应力极限。因此，故障模式变为金属化短路模式，而不引起层间电介质裂纹。热应力模拟和实验确定，由于SiC的热膨胀作用在层间电介质上的应力随着短路故障时间而变化，从而导致故障模式改变。
The aim of this article is to elucidate the short-circuit failure mechanism of SiC metal–oxide–semiconductor field-effect transistors that cause mechanical failure of the interlayer dielectric adjacent to the gate, to find the relationship between the short-circuit withstand capability and short-circuit failure time, and to classify failure modes by the short-circuit failure time. When the short-circuit failure time is shorter than the critical time, the stresses acting on the interlayer dielectric caused by the thermal expansion of the SiC die exceed the fracture stress limit of the oxide films. Therefore, cracks occur at the interlayer dielectric between the gate and the source. In this case, the short-circuit withstand capability can be predicted by thermal theory because the thermal expansion of the SiC die is determined by the temperature rise. However, when the short-circuit failure time is longer than the critical time, the stresses acting on the interlayer dielectric are less than the fracture stress limit of the oxide films. Thus, the failure mode changes to metallization short mode without causing interlayer dielectric cracks. Thermal stress simulations and experiments ascertain that the stress acting on the interlayer dielectric due to the thermal expansion of SiC varies with the short-circuit failure time, resulting in an altered failure mode.