Thermal Characteristics of 3kV, 600A 4H-SiC Flat-Package pn Diodes

3kV, 600A 4H-SiC high-temperature flat-package diodes have been developed for use in electricity supply. They consist of a pressure contact flat package and include five 6 mm x 6 mm SiC diode chips. These flat-package diodes have a thermal resistance of 0.21 deg/W, which is ten times the silicon thermal resistance, because the SiC diode chip is smaller than a Si diode chip. In order to lower the thermal resistance, it is necessary to increase the number of SiC chips in the flat package due to the difficulty of making a large-area SIC chip. The SiC pn flat package diode can achieve the same thermal resistance value at only half the chip area. The transient thermal impedance becomes saturated at nearly 1 s. In contrast, the Si diode's transient thermal impedance is saturated at 50 s. If a short circuit current flows for 50 ms, the SiC pn flat package diode withstands greater pulse loads than the Si diode at temperatures above Tjmax = 200 degrees C. For example, the SiC diode withstands 2.3 times as much energy as the Si diode at Tjmax = 500 degrees C. (C) 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(4): 1-7, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20978