5-6-4-1 SiC High-Power Rectifiers

The high-power diode rectifier is a critical building block of power conversion circuits. Recent reviews of experimental SiC rectifier results are given in References 3, 134, 172, 180, and 181. Most important SiC diode rectifier device design trade-offs roughly parallel well-known silicon rectifier trade-offs, except for the fact that current densities, voltages, power densities, and switching speeds are much higher in SiC. For example, semiconductor Schottky diode rectifiers are majority carrier devices that are well known to exhibit very fast switching owing to the absence of minority carrier charge storage that dominates (i.e., slows, adversely resulting in undesired waste power and heat) the switching operation of bipolar pn junction rectifiers. However, the high breakdown field and wide energy bandgap permit operation of SiC metal–semiconductor Schottky diodes at much higher voltages (above 1 kV) than is practical with siliconbased Schottky diodes that are limited to operation below ~200 V owing to much higher reverse-bias thermionic leakage.