70 mΩ / 600 V Normally-off GaN Transistors on SiC and Si Substrates

O. Hilt1, R. Zhytnytska1, J. Böcker2, E. Bahat-Treidel1, F. Brunner1, A. Knauer1, S. Dieckerhoff2 and J. Würfl1

Published in:

Proc. 27th International Symposium on Power Semiconductor Devices & IC's (ISPSD 2015), May 10-14, Hong Kong, China, pp. 237-240 (2015).

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Abstract:

The static and dynamic electrical performance of normally-off p-GaN gate AlGaN/GaN HFETs, manufactured on SiC and on Si substrates are compared. By implementing a ptype GaN gate, normally-off operation with 1 V threshold voltage has been realized for 70 mΩ / 600 V transistors on both substrates. The GaN-on-SiC devices out-perform Si-based superjunction MOSFETs in terms of gate charge and switching energy and feature a low area-specific on-state resistance, also when considering the full chip area. The higher thermal impedance of the GaN-on-Si devices is reflected in a reduced maximum drain current for pulse lengths > 1 µs. However, no significant thermal effect was found for lower pulse powers as targeted for efficient power switching.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
2 Power Electronics Research Group, Technical University of Berlin, Berlin, Germany

Keywords:

GaN; normally off; dynamic on-state resistance; dispersion; switching; self heating.