Semiconductor Materials Seal Role in Power Devices

摘要

Power control using power electronics is based on low-resistant, high-speed switching technology achieved by power devices. It can be safely said that power control performance depends on the performance of power devices. Against this backdrop, manufacturers are pining high hopes on wide bandgap semiconductors that have wider band- gaps than silicon in order to further improve the performance of power devices. Among various kinds of wide bandgap semiconductors, silicon carbide (SiC), gallium nitride (GaN) and gallium oxide (Ga_2O_3) attract attention as materials for power devices. Using these materials makes it possible to reduce conduction resistance at On-operation, enabling the achievement of low-loss devices. In addition, they can operate under high temperatures. In particular, SiC has high thermal conductivity, and enables the downsizing of cooling devices of power electronics devices. SiC diodes (Schottky barrier diodes [SBDs]) have been widely put to practical use, including inverters of home electric appliances, industrial equipment and railway cars. Furthermore, SiC metal-oxide semiconductor field-effect transistor (SiC-MOSFET) and GaN high electron mobility transistor (GaN-HEMT) devices have also begun to be incorporated in inverters of power conditioner systems (PCS) for photovoltaic power generation systems, and commercial products for railway and automotive applications.