Evolution of Drift-Free, High Power 4H-SiC PiN Diodes


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The PiN diode is an attractive device to exploit the high power material advantages of 4H-SiC. The combination of high critical field and adequate minority carrier lifetime has enabled devices that block up to 20 kV and carry 25 A. Furthermore, these devices exhibit fast switching with less reverse recovery charge than commercially available Si PiN diodes. The path to commercialization of the 4H-SiC PiN diode technology, however, has been hampered by a fundamental problem with the forward voltage stability resulting from stacking fault growth emanating from basal plane screw dislocations (BPD). In this contribution, we highlight the progress toward producing stable high power devices with sufficient yield to promote commercial interest. Two independent processes, LBPD1 and LBPD2, have been shown to be effective in reducing the BPD density and enhancing the forward voltage stability while being compatible with conventional power device fabrication. Applying the LBPD1 and LBPD2 processes to 10 kV (20 A and 50 A) 4H-SiC PiN diode technology has resulted in a dramatic improvement in the total device yield (forward, reverse, and forward drift yields) from 0% to >20%. The LBPD1 process appears to be more robust in terms of long term forward voltage stability.



Materials Science Forum (Volumes 527-529)

Edited by:

Robert P. Devaty, David J. Larkin and Stephen E. Saddow




M. K. Das et al., "Evolution of Drift-Free, High Power 4H-SiC PiN Diodes", Materials Science Forum, Vols. 527-529, pp. 1329-1334, 2006

Online since:

October 2006




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DOI: https://doi.org/10.4028/0-87849-425-1.141

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DOI: https://doi.org/10.4028/0-87849-425-1.1355

[5] [10] [15] [20] [25] [30] 0 0. 5 1 1. 5 2 2. 5 3 3. 5 4 Forward Voltage (V) Diode Current (A) Initial After 1000 h.

[5] [10] [15] [20] 250. 0 1. 0 2. 0 3. 0 4. 0 5. 0 Forward Voltage (V) Diode Current (A) Initial After 2000 h Fig. 6. Long term forward bias stress of packaged 10 kV, 20 A PiN diodes indicates that the KOH based LBPD1 process is more robust than the LBPD2 process in terms of long term VF stability. LBPD2 LBPD1.