3.1 Steady-State Current-Voltage Characteristics of Low-Voltage Thyristor Structures

The current-voltage characteristics of 6H-SiC thyristors with a forward breakover voltage close to 100 V were measured up to a current density j 5 x 10 ³A/cm ² in Ref. ^[54]. For this current density the forward voltage drop V was 10 V, which is significantly larger than V values for identically rated GaAs and Si thyristors at the same current densities. This result made questionable practical use of SiC thyristors at high and super high current densities.

The steady-state current- voltage characteristics in 4H-SiC thyristors with a forward breakover voltage of about of 400V at very high current density (up to 7 10 ⁴ A/cm ²) were investigated in Refs ^{[55] [56]}. The voltage drop across SiC thyristors has been found to be sufficiently less than the drop across 6H-SiC thyristor described in ^[54] and substantially less than the drop across identically rated Si and GaAs thyristors.

The cross-section of low-voltage p ⁺np ^?n 4H-SiC thyristor is shown in Fig. 1. The parameters of the structures are described in Section 2.1.

Curve 1 in Fig. 11 shows the dependence of the current density j versus voltage drop V at 300 K.

It is seen that the curve consists of two characteristic parts. At small current densities j < 300 400 A/cm ², the "on" state...