Dramatic frequency boost for SiC power MOSFETs

US startup NoMIS Power has made a significant breakthrough in improving the short-circuit withstand time (SCWT) of SiC MOSFETs while keeping the on resistance unchanged. This development addresses a major obstacle hindering the widespread adoption of SiC technology in high-power applications and enables higher frequency operation. Consequently, smaller magnetics can be used for more compact and lighter power systems.

Unlike the typical SCWT of 2 to 3us, the latest 1.2kV, 80 mΩ MOSFET boasts a time of 5 µs, enhancing the reliability of devices. By enhancing packaging to impact junction-to-case thermal capacitance and implementing innovative thermal management techniques with high heat transfer coefficients, the overall SCWT can be increased up to four times that of current devices.

This achievement was made possible by balancing the trade-off between the specific on resistance (Ron,sp) and SCWT through a proprietary SiC MOSFET fabrication design and process flow, which can be customized based on the specific application requirements. Through complete optimization of SiC MOSFETs with extended SCWT using this approach, NoMIS Power aims to further enhance the SCWT while minimizing the impact on the Ron. The university spinout, headquartered in Albany, New York, showcased significant device improvements at the IEDM conference last year.

One of the key highlights of this advancement is the launch of the 1200V SiC MOSFET by NoMIS Power. These SiC devices undergo rigorous screening for latent defects and facilitate easier gate driver desaturation (dSat) design for high di/dt and dv/dt, enabling faster switching frequencies of up to hundreds of kHz. The extended short-circuit withstand time ensures robust and reliable performance in critical applications, reinforcing the durability of SiC-based power systems.

Applications that are sensitive to electromagnetic interference and cannot solely rely on digital control and sensing schemes to detect and respond to short-circuit events can now effectively leverage SiC MOSFETs. "At NoMIS Power, we have dedicated significant efforts to device architecture engineering, resulting in a notable advancement in SiC short-circuit withstand time," stated Woongje Sung, the CTO at NoMIS Power. "We believe this accomplishment offers valuable benefits to the power electronics community, empowering engineers to integrate SiC solutions with increased confidence in applications where robustness is paramount."

These innovative devices will be on display at APEC 2025 this week in Atlanta, Georgia, showcasing the latest advancements in SiC MOSFET technology and the potential they hold for enhancing the performance and reliability of power systems across various industries.