Characterization of 15 kV SiC n-IGBT and its Application Considerations for High Power Converters Arun Kadavelugu, Subhashish Bhattacharya FREEDM Systems Center North Carolina State University Raleigh, NC, USA. Sei-Hyung Ryu, Edward Van Brunt, David Grider, Anant Agarwal* Cree, Inc. Durham, NC, USA. *Currently, with the US. Dept. of Energy. Scott Leslie Powerex, Inc Youngwood, PA, USA. Abstract—The 4H-SiC n-IGBT is a promising power semiconductor device for medium voltage power conversion. Currently, Cree has successfully built 15 kV n-IGBTs. These IGBTs are pivotal for the smart grid power conversion systems and medium voltage drives. The need for complex multi-level topologies or series connected devices can be eliminated, while achieving reduced power loss, by using the SiC IGBT. In this paper, characteristics of the 15 kV n-IGBT have been reported for the first time. The turn-on and turn-off transitions of the 15 kV, 20 A IGBT have been experimentally evaluated up to 11 kV. This is highest switching characterization voltage ever reported on a single power semiconductor device. The paper includes static characteristics up to 25 A (forward) and 12 kV (blocking). The dependency of the power loss with voltage, current and temperature are provided. In addition, the basic converter design considerations using this ultrahigh voltage IGBT for high power conversion applications are presented. Also, a comparative evaluation is reported with an IGBT with thicker field-stop buffer layer as a means to show flexibility in choosing the IGBT design parameters based on the power converter frequency and power rating specification. Finally, power loss comparison of the IGBTs and MOSFET is provided to consummate the results for a complete reference. I. INTRODUCTION The 6.5 kV Silicon (Si) IGBTs are the highest voltage power semiconductor devices commercially available for high switching frequency power conversion. But, the growing interest in smart-grid power electronics at distribution voltage levels requires the Si IGBTs to be either connected in series or using multi-level converter topologies. The series connection requires expensive snubber circuits for voltage balancing and results in significant power loss [1]. On the other hand, the multilevel topologies need complex controllers and suffer from voltage and power balancing problems [2]. Owing to these problems, there has been a considerable interest to develop high voltages devices (> 10 kV) using SiC [3], [4]. The 10 kV 4H-SiC MOSFETs are viable high voltage devices with low on-resistance while allowing switching frequencies beyond 20 kHz [4]. But, like in the case of Si, MOSFETs are not feasible for higher voltage due to increased drift resistance (due to unipolar nature) which is amplified further with temperature. In [5], it is predicted that approximately above 9 kV, IGBTs are better than MOSFETs, for the same foot-print size. Initially, IGBTs were designed with p-type drift due to practical limitation in preparing low resistivity p-SiC substrates required for the n- IGBTs [6]. However, with advances in the SiC technology, n-IGBTs have also been built [7], [8]. As predicted, the n- IGBTs are superior to p-IGBTs in terms of on-state drop as well as switching characteristics [8]. The following section of the paper reports the performance of the state-of-the-art 15 kV, 20 A, n-IGBT. In Fig. 1, the cross-section of the IGBT is shown. The thicknesses of the field-stop buffer layer and the drift region are 2 µm and 140 µm respectively as shown. Figure 1: Cross-sectional view of the 15 kV n-IGBT. This work is supported by ARPA-E Contract #DE-AR0000110. 2528 U.S. Government work not protected by U.S. copyright