Product Key Points

Development of 4th-Generation SiC MOSFET, Achieving Industry’s Lowest On-Resistance : Support for xEV/EV Main Inverters, Higher Battery Voltages


Points of this article

・As recent engineering trends, much emphasis has been placed on miniaturization, performance enhancement, and design properties.

・Because of these trends, heat generation has increased and heat dissipation has worsened, so that thermal design has become more difficult.

・It is important to examine whether existing criteria for evaluation of thermal designs can accommodate these current engineering trends.

ROHM has developed 1200 V fourth-generation SiC MOSFETs that are optimal for automotive power train systems, including the main inverters, as well as power supplies for industrial equipment. These fourth-generation SiC MOSFETs achieve the industry’s lowest* on-resistance, and are anticipated to provide support for high-efficiency, miniaturized and lightweight electric drive systems in next-generation electric vehicles (xEVs), for miniaturization and improved efficiency in the main inverter systems that are the core of vehicle propulsion, and for higher battery voltages (800 V) and reduced charging times accompanying the increased battery capacities of electric vehicles (EVs). At present, bare chip samples can be provided.
*ROHM survey, June 17 2020

<Features of the 1200 V Fourth-Generation SiC MOSFET>

  • ・ROHM’s proprietary double trench structure was further developed, to reduce the on-resistance by approximately 40% per unit area compared with conventional products, without sacrificing the short-circuit withstand time
  • ・By greatly reducing parasitic capacitance, switching losses are cut about 50% compared with conventional products
  • ・Through the above features, miniaturization and reduced power consumption are possible in various power conversion applications such as inverters and power supplies

Proprietary Trench Structure Developed to Realize Industry’s Lowest On-Resistance

In 2015, ROHM succeeded in the world’s first mass production of SiC MOSFETs adopting a proprietary trench structure, and has persisted in efforts to improve the performance of SiC power devices. Reduction of the on-resistance involves a tradeoff with a shorter resulting short-circuit withstand time, but in the newly developed fourth-generation SiC MOSFETs, by further developing a proprietary double-trench structure, ROHM succeeded in lowering the on-resistance by about 40% per unit area compared with current devices, without sacrificing the short-circuit withstand time.

Parasitic Capacitance Greatly Reduced, Switching Losses Cut 50%

Generally in MOSFETs there is a tendency for various parasitic capacitances to increase as the on-resistance is lowered and larger currents are passed. Because switching losses grow as parasitic capacitances increase, limits are imposed on the fast switching operation that is normally a feature of SiC. In these fourth-generation devices, however, by dramatically reducing the gate-drain capacitance (CGD), it was possible to reduce switching losses by roughly 50% compared with current devices.

Information on Downloading Technical Documents

Downloadable materials, including lecture materials from ROHM-sponsored seminars and a selection guide for DC-DC converters, are now available.

Download Technical Documents

Downloadable materials, including lecture materials from ROHM-sponsored seminars and a selection guide for DC-DC converters, are now available.

Product Key Points