SXRT Investigations on Electrically Stressed 4H-SiC PiN Diodes for 6.5 kV
4H-SiC PiN diodes for 6.5 kV were manufactured on both 4° and 8° off-cut substrates and subjected to an electrical stress test on wafer level and subsequent analysis of structural defects present in the active area of the diodes. For 8° off-cut diodes, the electrical characteristics with respect to leakage current and forward voltage drift are worse than the electrical characteristics of 4° off-cut diodes. Furthermore, a large number of stacking faults was found in 8° off-cut diodes, but little evidence for bipolar degradation was found in 4° off-cut diodes. Therefore, bipolar degradation was significantly reduced by avoiding BPDs in the active area of PiN diodes, i.e. by the use of 4° off-cut substrates. Furthermore, a strong correlation was found between the electrical screening test on wafer level and critical defects.
Alexander A. Lebedev, Sergey Yu. Davydov, Pavel A. Ivanov and Mikhail E. Levinshtein
B. Kallinger et al., "SXRT Investigations on Electrically Stressed 4H-SiC PiN Diodes for 6.5 kV", Materials Science Forum, Vols. 740-742, pp. 899-902, 2013