Semiconductors

† Fuji Electric Co., Ltd. chip having reverse blocking capability for use in matrix converters and advanced NPC (A-NPC: advanced neutral-point-clamped) type inverters*2 that can be used to realize higher effi ciency in equipment. Using this chip, an IGBT module for use in an A-NPC circuit in combination with a conventional IGBT as shown in Fig. 1, and a bidirectional switching IGBT module for use in a matrix converter have been developed. Fuji Electric has developed IGBT modules and IPMs (intelligent power modules) for applying to hybrid vehicles, a plated IGBT having twice the current density of a general-purpose IGBT using a doublesided cooling package structure, a diode chip, and the like. All of these devices are either 600 V or 1,200 V products. In recent years, the motor capacities of hybrid and electric vehicles have increased, and with the increase in motor output current, higher effi ciency through optimizing the module voltage has increasingly been demanded. In response to this demand, Fuji Electric has developed a 750 V IGBT module for mild hybrid vehicles that realizes an approximate 30% reduction in loss compared to previous modules. In the fi eld of power modules, technical development to improve further the performance of IGBTs as key devices in the “energy and environment” fi eld, and product development to meet customer needs are being carried out. 3. Next-generation Devices As 6th generation IGBTs, which are the mainstream devices of today, are approaching the theoretical performance limit of silicon, dramatic performance improvements as in the past are no longer expected. Therefore, attention has shifted to next-generation devices that use silicon carbide (SiC) and gallium nitride (GaN) materials. Since 2009, Fuji Electric has actively been developing these next-generation devices jointly with outside organizations, and is endeavoring to accelerate development aiming for practical application. Using SiC material, in joint development with the National Institute of Advanced Science and Technology, Fuji Electric is advancing the development of MOSFETs (metal oxide semiconductor fi eld effect transistors) and schottky barrier diodes. Through using SiC devices, loss can be reduced by 50% or more compared to conventional silicon, and SiC technology is considered to hold promise for making signifi cant contributions to technical innovation in power electronic devices. Meanwhile, for GaN device development, Fuji Electric and the Furukawa Electric Co. have jointly established the Technical Research Association for Next-Generation Power Devices, and are advancing research toward practical applications. GaN can be formed on a silicon wafer, and is therefore potentially less expensive than SiC.