Anomalous Electrical Behavior of 4H-SiC Schottky Diodes in Presence of Stacking Faults

In this work, we investigated the impact of crystallographic defects (specifically stacking faults, SFs) on the mechanisms of the current transport in 4H-SiC Schottky contacts. The electrical characteristics were studied under both forward and reverse bias. In particular, while the presence of SFs under the contact did not show a significant impact on the forward characteristics of the Schottky diode, a significant increase in the leakage current occurred under reverse bias in defective diodes. This anomalous behavior can be explained by a space-charge limited current model, consistent with the presence of a trapping state distribution in the 4H-SiC gap. An increase of the reverse bias above 30 V leads to a complete trap filling. The weak temperature-dependence of the leakage current observed at highest voltage suggests that a tunneling of the carriers through the barrier can be also present.