Peak Voltage and Switching Slope Dependency of Gate Switching Instability in SiC MOSFET

Abstract:

The pursuit of ever-higher system efficiency and power density in power electronic applications paves the way for an increased utilization of wide bandgap semiconductor devices such as silicon carbide (SiC) MOSFETs, due to reduced conduction and switching losses compared to silicon. For real-world application reliable operation along its lifetime is of utmost importance. To assure robust operation in electric drives and traction inverters SiC MOSFETs are switched bipolar to prevent parasitic turn on. Recently, it has been shown that not only bias temperature instability, but also gate-switching instability in bipolar switched applications has to be considered as a reliability concern for SiC MOSFET. While in gate switching stress tests usually only critically damped conditions are investigated irrespective of rise and fall times, in real-world applications gate voltage overshoots may occur and a broad variety of slew rates may be used depending on the individual power converter design. Therefore, this work investigates the influence of gate voltage overshoot and voltage slopes on threshold voltage aging using high frequencies and online degradation monitoring. It is shown that overshoots have a dominating impact on the overall degradation, while the gate voltage slope impacts minorly.

• Periodical: Key Engineering Materials (Volume 1054)
• Pages: 1-8
• DOI: https://doi.org/10.4028/p-KxTj4u
• Online since: May 2026
• Authors: Ruben Schnitzler*, Tobias Fink, David Halmer, Dominik Koch, Ingmar Kallfass
• Keywords: Gate Switching Instability (GSI), Gate Switching Stress, Reliability, Threshold Voltage Degradation

References

[1] J. Wang and X. Jiang, "Review and analysis of sic mosfets' ruggedness and reliability," IET Power Electronics, vol. 13, no. 3, p.445–455, 2020.

DOI: 10.1049/iet-pel.2019.0587

[2] T. Aichinger and M. Schmidt, "Gate-oxide reliability and failure-rate reduction of industrial sic mosfets," in 2020 IEEE International Reliability Physics Symposium (IRPS), IEEE, 2020.

DOI: 10.1109/irps45951.2020.9128223

[3] T. Aichinger, G. Rescher, and G. Pobegen, "Threshold voltage peculiarities and bias temperature instabilities of sic mosfets," Microelectronics Reliability, vol. 80, p.68–78, 2018.

DOI: 10.1016/j.microrel.2017.11.020

[4] Schnitzler, R., Halmer, D., Fink, T., Koch, D., & Kallfass, I. (2025, May). 10 MHz Accelerated Gate-Switching Stress Tests Utilizing In-Situ Degradation Monitoring for SiC MOSFETs. In PCIM Conference 2025; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (pp.1734-1742). VDE.

DOI: 10.1109/ecce-europe62795.2025.11238631

[5] X. Zhong et al., "Bias temperature instability of silicon carbide power mosfet under ac gate stresses," IEEE Transactions on Power Electronics, p.1, 2021.

DOI: 10.1109/tpel.2021.3105272

[6] JEDECTRAVEL and J.-. 2, "Guideline for evaluating bias temperature instability of silicon carbide metal-oxidesemiconductor devices for power electronic conversion,".

DOI: 10.3403/30499100

[7] P. Salmen, M. W. Feil, K. Waschneck, H. Reisinger, G. Rescher, and T. Aichinger, "A new test procedure to realistically estimate end-of-life electrical parameter stability of sic mosfets in switching operation," in 2021 IEEE International Reliability Physics Symposium (IRPS), IEEE, 2021.

DOI: 10.1109/irps46558.2021.9405207

[8] D. Scholten, J. Baringhaus, D. Krebs, and S. Noll, "Hypothesis to explain threshold drift due to dynamic bipolar gate stress," Materials Science Forum, vol. 1090, p.159–164, 2023.

DOI: 10.4028/p-bt3i95

[9] S. Thiele, C. Herrmann, D. Yang, M. Neumeister, and T. Basler, "Gate switching instability of sic mosfets under simultaneously high drain-source voltage and high frequency acceleration," in 2024 36th International Symposium on Power Semiconductor Devices and ICs (ISPSD), IEEE, 2024, p.136–139.

DOI: 10.1109/ispsd59661.2024.10579621

[10] M. Xie, P. Sun, K. Wang, Q. Luo, and X. Du, "Online gateoxide degradation monitoring of planar sic mosfets based on gate charge time," IEEE Transactions on Power Electronics, vol. 37, no. 6, p.7333–7343, 2022.

DOI: 10.1109/tpel.2022.3142139

[11] T. Grasser et al., "A recombination-enhanced-defect-reactionbased model for the gate switching instability in sic mosfets," in 2024 IEEE International Reliability Physics Symposium (IRPS), IEEE, 2024, 3B.1–1–3B.1–7.

DOI: 10.1109/irps48228.2024.10529465

[12] M. W. Feil et al., "On the frequency dependence of the gate switching instability in silicon carbide mosfets," Materials Science Forum, vol. 1092, p.109–117, 2023.

DOI: 10.4028/p-6g5v7s

[13] M. W. Feil et al., "Gate switching instability in silicon carbide mosfets—part i: Experimental," IEEE Transactions on Electron Devices, vol. 71, no. 7, p.4210–4217, 2024.

DOI: 10.1109/ted.2024.3397636

[14] D. B. Habersat and A. J. Lelis, "Ac-stress degradation and its anneal in sic mosfets," IEEE Transactions on Electron Devices, vol. 69, no. 9, p.5068–5073, 2022.

DOI: 10.1109/ted.2022.3190815

[15] "Ecpe, "qualification of power modules for use in power electronics converter units in motor vehicles," ecpe guideline aqg 324, rev. 03.1/2021, 2019.," in.

[16] E. H. Nicollian and J. R. Brews, MOS (metal oxide semiconductor) physics and technology (Wiley classics library), Wiley classics library ed. Hoboken, NJ: Wiley-Interscience, 2003.

[17] Ruben Schnitzler, Tobias Fink, Dominik Koch, David Halmer and Ingmar Kallfass "Parameter-Dependent Analysis of Gate Switching Instability in SiC MOSFETs", Accepted, to be published at ECCE europe 2025.

DOI: 10.1109/ecce-europe62795.2025.11238631

[18] Huerner, A., Sochor, P., Sun, Q., Feil, M. W., & Elpelt, R. (2022, May). Influence of turn-off gate-voltage undershoots on the turn-on behavior of SiC MOSFETs. In PCIM Europe 2022; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (pp.1-8). VDE.

[19] Zeng, Z., & Li, X. (2017). Comparative study on multiple degrees of freedom of gate drivers for transient behavior regulation of SiC MOSFET. IEEE Transactions on Power Electronics, 33(10), 8754-8763.

DOI: 10.1109/tpel.2017.2775665