Day: 14 March 2025

NoMIS Power has announced a major breakthrough in improving the short-circuit withstand time (SCWT) of SiC MOSFETs. This innovation addresses one of the key challenges limiting the widespread adoption of SiC technology in high-power applications.

Silicon carbide (SiC) devices have gained prominence in power electronics due to their high efficiency, fast switching, and superior thermal performance. However, their historically lower short-circuit robustness compared to silicon-based IGBTs has posed challenges for their use in high-voltage and high-reliability environments, such as industrial drives, electric vehicles, and grid applications. NoMIS Power’s latest advancement significantly extends the SCWT of SiC MOSFETs to a minimum of 5 µs (Fig. 1), compared to the current industry standard of 2-3 µs, with no deleterious effect on specific on-resistance (R_on,sp) (Fig. 2). This enhancement greatly improves reliability and unlocks new opportunities for system designers seeking to maximize performance while maintaining fault tolerance.

Figure 1: Drain currents of the NoMIS Power SiC MOSFET and NoMIS Power SiC MOSFET with long SCWT under short-circuit conditions right before failure. Drain currents of the 1.2 kV, 80 mΩ SiC MOSFET (dark blue) and the long SCWT 1.2 kV, 80 mΩ SiC MOSFET (light blue) from NoMIS Power are compared. The measurement for short-circuit was conducted under the following conditions: Rg of 20 Ω, Vgs of 20 V, and a Vds of 800 V.

By tuning the trade-off between R_on,sp and SCWT using NoMIS Power’s proprietary SiC MOSFET fabrication design and process flow, the performance shown in Fig. 1 & Fig. 2 was achieved; and can be similarly managed depending on the specific application. Complete optimization of SiC MOSFETs with long SCWT using this approach will allow NoMIS Power to further extend the SCWT while maintaining negligible impact on R_on,sp.

Figure 2: Typical output characteristics of NoMIS Power 1.2 kV, 80 mQ SiC MOSFET and NoMIS Power 1.2 kV, 80 mQ SiC MOSFET with long SCWT showing no significant negative impact on on-resistance.

“At NoMIS Power, we have focused extensively on device architecture engineering, leading to a significant advancement in SiC short-circuit withstand time,” said Woongje Sung, CTO at NoMIS Power. “We believe this achievement provides valuable advantages to the power electronics community, helping engineers integrate SiC solutions with greater confidence in applications where robustness is critical.” 

NoMIS Power’s long SCWT devices are well-screened for latent defects and offer easier gate driver desaturation (dSat) design for high di/dt and dv/dt, enabling faster switching frequencies of up to hundreds of kHz. Initial test results demonstrate a 2X to 4X increase in short-circuit withstand time compared to existing SiC devices, positioning NoMIS Power’s technology as a frontrunner in the next generation of power semiconductors. Additionally, when coupled with packaging innovations that impact junction-to-case thermal capacitance, alongside novel thermal management techniques with high heat transfer coefficients, the overall SCWT of the SiC MOSFET can be further improved. 

The impact of this innovation extends across multiple industries, including renewable energy, electric transportation, and high-power industrial applications. A longer short-circuit withstand time ensures rugged and reliable performance in critical applications, reinforcing the robustness of SiC-based power systems. For example, built-in redundancy of the SiC MOSFETs inside power converters, which impacts costs as well as power density, can be reduced. Furthermore, applications sensitive to electromagnetic inference, that cannot solely rely on digital control and sensing schemes to detect and act upon short-circuit events, will now be able to effectively utilize SiC MOSFETs with lower risk. As SiC adoption accelerates, NoMIS Power’s breakthrough will play a pivotal role in enhancing the reliability and safety of SiC-based power converters and systems.

NoMIS Power is showcasing this breakthrough technology at APEC 2025, March 16-20, Atlanta, GA, Booth 548 along with its expanded range of SiC discretes and power modules.

Original – NoMIS Power