What changes when Si MOSFET/IGBT is replaced with SiC MOSFET?

By replacing Si IGBT with SiC MOSFET, it is possible to reduce the size and weight of the equipment and achieve highly efficient power conversions due to high frequency operation. Comparison of characteristics of Si MOSFET/IGBT and SiC MOSFET are shown in Table1.

＊：Fast Recovery Diode　　★：The higher the number, the better the relative.
Electrical Characteristics Symbol
（Improvement）		 Relation on application use Si material SiC material
MOSFET IGBT
(Built-in *FRD)		 MOSFET
(Built-in SBD)
High Voltage range
(Large)		 High Voltage range of set ★★ ★★★ ★★★
Switching Loss
(Small)		 Efficiency
(Smallness of the loss at the Turn-on/off time)		 ★★ ★ ★★★
Forward Voltage of Built in Diode
(Small)		 Efficiency
(Smallness of the loss at the energy for Diode)		 ★★ ★★ ★★★
Reverse recovery time of Built in Diode trr
(Small)		 Efficiency
(Smallness of the loss at the Turn-on)		 ★ ★★ ★★★


Table 1. Comparison of characteristics of Si MOSFET, Si IGBT and SiC MOSFET

When Toshiba’s SiC MOSFET and Si IGBT are switched at Ta =25°C, the switching loss waves are  shown in Figures 1(a) and 1(b). For SiC MOSFET, the turn-off loss and turn-on loss are reduced by 65% compared to Si IGBT.

i) The reduction in turn-on loss is due to the smaller trr・Irr of SiC MOSFET's built-in SiC SBD affecting the loss than Si IGBT's built-in Si FRD.

ii) The reduction of turn-off loss is influenced by the fact that SiC MOSFET has no accumulation of minority carrier and no loss due to tail current as in Si IGBT.

Figure 1(a). Turn-on Switching Loss of SiC MOSFET and Si IGBT
Figure 1(a). Turn-on Switching Loss of SiC MOSFET and Si IGBT
Figure 1(b). Turn-off Switching Loss of SiC MOSFET and Si IGBT
Figure 1(b). Turn-off Switching Loss of SiC MOSFET and Si IGBT

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