TURN-ON PROCESS IN HIGH-VOLTAGE 4H-SIC THYRISTORS

The turn-on process and steady state current-voltage characteristics h ave been investigated in 4H-SiC thyristors with a forward breakover vo ltage close to 700 V and pulse switch current density of 16 000 A cm(- 2). The current rise constant tau(r) decreases monotonically with incr easing temperature: tau(r) approximate to 10.5 ns at T = 300 K and tau (r) approximate to 1.2 ns at T = 500 K at high bias U-0 greater than o r equal to 300 V. The value of tau(r) approximate to 1.2 ns is the low est observed value for SiC thyristors. At very high current density j greater than or equal to 5 x 10(3) A cm(-2) the residual voltage drop on 4H-SiC thyristors is lower than on identically rated Si thyristors. The voltage drop U-d0 decreases monotonically with increasing tempera ture.