New Industry Products

ROHM SiC MOS Module, without a Schottky Diode Enters High-Volume Production

March 20, 2013 by Jeff Shepard

ROHM has started mass-production of a 1200V/180A-rated SiC MOS module BSM180D12P2C101 for inverters/converters used in industrial equipment, photovoltaic power conditioners and the like. This new module is the first to incorporate a power semiconductor comprised of just an SiC MOSFET, increasing the rated current to 180A for broader applicability while contributing to lower power consumption and greater compactness.

Next-generation SiC MOSFET technology is utilized to minimize conduction degradation of the body diode, eliminating the need for diode rectification. This makes it possible to increase the mounting area for higher current handling capability while maintaining the same compact form factor. In addition, by improving processes and device structures related to crystal defects ROHM was able to overcome all problems related to reliability, including that of the body diode. The result is 50% less loss compared with conventional Si IGBTs used in general-purpose inverters. This decreased loss, along with an operating frequency greater than 50kHz, ensures compatibility with smaller peripheral components for greater end-product miniaturization.

Switching characteristics are maintained using a simple MOS structure for minimal switching loss with no tail current. Switching characteristics are maintained even without an SBD. And unlike Si IGBTs, no tail current is generated, reducing loss by more than 50% for greater energy savings. In addition, switching frequencies over 50kHz are supported (impossible with Si IGBTs), contributing to smaller, lighter peripheral devices.

Reverse conduction is possible for high efficiency synchronous rectification. General-purpose Si IGBT devices are not capable of conduction in the reverse direction. In contrast, the body diode in ROHM's SiC MOSFET always conducts in reverse. Also, depending on the Gate signal input the MOSFET can operate in either direction for lower ON resistance vs. using just the diode. These reverse direction conduction characteristics allow for high efficiency synchronous rectification in the 1000V range - higher than diode rectification.

Body diode conduction degradation is eliminated, enabling conduction over 1000 hours with no performance loss. Clarifying the mechanism by which defects are spread based on body diode conduction makes it possible to minimize the primary factors through process and device construction With general-purpose products the ON resistance increases significantly after 20 hours. In contrast, ROHM's new module ensures no ON resistance increases - even after more than 1000 hours.