Turn-on Process in High Voltage 4H-SiC Thyristors

ABSTRACTThe turn-on process and the steady state current-voltage characteristics have been investigated in 4H-SiC thyristors with a forward breakover voltage close to 700 V and pulse switch current density of 16 000 A/cm2. The rise current constant, τr, has been found to decrease monotonically with temperature: τr, ≈ 10.5 nsec at T = 300 K and τr ≈ 1.2 nsec at T = 500 K at high bias Uo ≥ 300 V. The value of τr ≈ 1.2 nsec is the lowest observed value for SiC thyristors. At very high current density, j ≥ 5 103 A/cm2, the residual voltage drop for 4H-SiC thyristors is lower than for identically rated Si thyristors. The voltage drop Udo decreases monotonically with temperature.