Low VF 4H-SiC N-i-P diodes using newly developed low-resistivity p-type substrates

Abstract

We fabricated 4H-SiC N-i-P (N-intrinsic-P) diodes using newly developed low-resistivity p-type substrates with higher acceptor concentrations than conventional substrate. N-i-P diodes with 10 μm thick n− drift layers were fabricated on both a low-resistivity p-type substrate and a conventional one to investigate the difference in substrate resistance and bipolar degradation with a heavily doped p-type buffer layer. The differential on-resistance of N-i-P diode, using low-resistivity p-type substrates was decreased to one third compared to the conventional case, and the difference was similar to the p-type substrates resistivity. No stacking faults expansion was observed up to 1100 A cm−2. N-i-P diodes with 233 μm thick n− drift layers were fabricated to demonstrate forward characteristics instead of an ultra-high voltage n-channel IGBTs. The forward characteristics of the N-i-P diodes with 233 μm thick n− drift layers at 200 °C showed low on-voltage 6.9 V and low differential on-resistance 32.2 mΩ cm2.