Degradation Assessment and Precursor Identification for SiC MOSFETs Under High Temp Cycling
Degradation Assessment and Precursor Identification for SiC MOSFETs Under High Temp Cycling
复制标题
SiC MOSFET 高温循环下的退化评估和前体识别
DOI：
10.1109/tia.2019.2891214
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发表时间：
2019
影响因子：
4.4
通讯作者：
B. Akin
中科院分区：
文献类型：
--
作者：
Enes Ugur;Fei Yang;S. Pu;Shuai Zhao;B. Akin
碳化硅功率MOSFET在高压、高频和高温应用中是硅器件的很有前途的替代品。由于有限的现场数据和潜在的不确定性，SIC设备的快速和广泛的部署带来了长期的可靠性问题，特别是对于任务和安全关键系统。因此，有必要研究碳化硅器件中的渐进退化和参数漂移，为自监测转换器开发系统集成退化监测工具，以便能够在最早阶段识别故障前兆，防止灾难性故障。本文对商用的碳化硅MOSFET在高温工作和高温摆动下的长期可靠性、与退化有关的关键先兆及其可能的原因进行了全面的分析。为此，离散的SIC器件进行电源循环，并在曲线跟踪器的帮助下以一定的间隔记录所有数据表参数。为了评估它们与开关老化/退化状态的相关性，给出了整个测试过程中电气参数的变化。其中，所有样品都观察到了与栅氧电荷陷阱相关的阈值电压漂移和相应的态电阻变化。对于某些样品，键合线跟开裂是导通电阻突然升高和体二极管电压升高的根本原因。通过故障器件的解封获得的故障分析支持关于老化先兆的讨论。最后，根据实际实施中的相关问题，对研究结果进行了评估，以确定电学参数作为老化前兆参数的适宜性。
Silicon carbide (SiC) power mosfets are promising alternatives to Si devices in high-voltage, high-frequency, and high-temperature applications. The rapid and widespread deployment of SiC devices raises long-term reliability concerns, particularly for mission and safety critical systems due to limited field data and potential uncertainties. Therefore, it is essential to investigate progressive degradations and parameter shifts in SiC devices to develop system integrated degradation monitoring tools for self-monitoring converters, which can recognize failure precursors at the earliest stage and prevent catastrophic failures. This paper presents a comprehensive long-term reliability analysis of commercially available SiC mosfets under high temperature operation and high temperature swing, degradation related key precursors, and possible causes behind them. For this purpose, discrete SiC devices are power cycled and all datasheet parameters are recorded at certain intervals with the aid of the curve tracer. Variation of electrical parameters throughout the tests is presented in order to assess their correlation with the aging/degradation state of the switch. Among them, gate oxide charge trapping related threshold voltage drift and corresponding on state resistance variation has been observed for all samples. For some samples, bond wire heel cracking is found to be the root cause of sudden on state resistance and body diode voltage increases. The discussions regarding aging precursors are supported by failure analysis obtained through the decapsulation of failed devices. Finally, the findings are evaluated in order to define the suitability of electrical parameters as an aging precursor parameter under the light of practical implementation related issues.