0620 Mw Rohm 4th Gen Mosfet Figure

4th-Generation SiC MOSFETs Boast Industry’s Lowest On-Resistance

June 17, 2020
These 1200-V devices provide high withstand voltages with low losses, making them apt for widespread adoption in the main drive inverters of EVs.

In recent years, the proliferation of next-generation electric vehicles (xEVs) has hastened the development of smaller, lighter, and more efficient electrical systems. Improving efficiency while decreasing the size of the drive system’s main inverter remains among the most important challenges, requiring further advancements in power devices. Onboard vehicle batteries are gaining in capacity so as to improve cruising range, while also moving to higher voltages (800 V) to meet demands for shorter charging times.

For power semiconductors, there is often a tradeoff between lower on-resistance and short-circuit withstand time, which is required to strike a balance for achieving lower power losses in SiC MOSFETs. In its new 4th-generation 1200-V, SiC power MOSFETs, ROHM was able to successfully improve this trade-off relationship and reduce on-resistance per unit area by 40% over conventional products without sacrificing short-circuit withstand time by further improving an original double-trench structure. In addition, significant reduction in the devices’ parasitic capacitance (which is a problem during switching) makes it possible to achieve 50% lower switching loss over the company’s previous generation of SiC MOSFETs.

As a result, the new SiC MOSFETs can deliver low on-resistance with high-speed switching performance, contributing to greater miniaturization and lower power consumption in a variety of applications, including automotive traction inverters and switching power supplies.

In 2015, ROHM began mass production of the industry-first trench-type SiC MOSFETs utilizing an original structure. In these new devices, the company has reduced on resistance by 40% compared to conventional products without sacrificing short-circuit withstand time by further improving its original double trench structure.

Generally, lower on resistances and larger currents tend to increase the various parasitic capacitances in MOSFETs, which can inhibit the inherent high-speed switching characteristics of SiC. However, ROHM was able to achieve 50% lower switching loss over conventional products by significantly reducing the gate-drain capacitance (Cgd).

Bare chip samples are available now with discrete packages to be offered in the future.