Abstract — This paper discusses the static and dynamic behavior of the body diode buried in SiC JFETs and SiC Schottky Barrier Diodes (SBDs). The device parameters are extracted from experimental results and their temperature dependencies are discussed. There is reverse current flow from source to drain in the channel of JFETs for on condition at low temperatures. In higher temperatures, it tends to flow through the body diode due to the increase of the resistance across the channel. The dynamic characteristics indicate that the reverse recovery phenomena of the body diode in a SiC JFET deteriorates with increasing temperature. It is therefore desirable to add an external SiC SBD for improving the static and dynamic behavior for high temperature operation of SiC JFETs. I. INTRODUCTION Silicon Carbide (SiC) as a semiconductor material has superior wide band gap characteristics, which cannot be attained by conventional silicon (Si) semiconductors, thereby making them well suited for constructing switching devices in power electronic circuits [1-11]. The superior characteristics of the SiC devices currently available are not enough to justify their higher costs when operating them at conditions similar to those of Si devices. Therefore, the authors are focusing on SiC devices for operation under extremely high ambient temperatures [12-14], a realm not available to Si devices [15-28]. In their previous work, the authors evaluated the static VI characteristics and the dynamic switching characteristics of SiC JFETs in their forward conduction operation [12,14], but they did not discuss the device characteristics in the reverse conduction operation, which is the focus of this paper. The studied SiC JFET[10-11] has a buried body diode which is similar to that of a general Si power MOSFET. The body diode can be used as a freewheeling diode, whose characteristics largely affect the performance of a converter. This paper characterizes the body diode in SiC JFETs with some device parameters extracted from experimental results, discusses the temperature dependency of the device performance, and then evaluates the feasibility of using the SiC JFET in a synchronous rectifier configuration. The latter is a typical application for a power FET with body diode even though the FET body diode has inferior performance compared to a discrete power switching diode. Thus, the paper also characterizes SiC Schottky Barrier Diodes (SBD) for the same operating conditions and discusses the shortcomings in the body diode of SiC JFETs. II. SPECIFICATION OF SIC DEVICES The type and rated value of the studied SiC JFET and SBDs are given in Table 1. They are packaged in a dedicated high temperature package, whose specification is also given in Table 1, to study the temperature dependency of the device characteristics from room temperature (25 o C) to extremely high temperature (450 o C). Both the JFET and SBD have vertical topology suited for heat transfer in power devices. The area of the JFET is 2.8 mm 2 , and SBD is 1.191 mm 2 (SIDC02D60SIC2) and 1.488 mm 2 (CPWR-0600S004), respectively. Characterization of SiC Diodes in Extremely High Temperature Ambient T. Funaki 1) a) , A. S. Kashyap 3) , H. A. Mantooth 3) ,J. C. Balda 3) , F. D. Barlow 3) , T. Kimoto 2) and T. Hikihara 1) TABLE I SiC DEVICE PARAMETERS Packaging Ni plated JEDEC, TO-258, 3 mil Al wire bond SiC JFET Manufacturer Type Rated current (Ids) Rated voltage (Vds) SiCED Vertical JFET, 2.5 A 1200 V 1 2 Manufacturer Type Rated current, voltage Infineon SIDC02D60SIC2 6 A, 600 V SiC SBD 3 Manufacturer Type Rated current, voltage Cree CPWR-0600S004 4 A, 600 V n+ n+ Source Source p p+ p+ Gate n- Drift region n Fieldstop 4H n+ Substrate Drain D S G Body diode D S G Body diode (a) Cross section (b) Device symbol Fig. 1: Configuration of the studied SiC JFET. 1,2) Kyoto University, Graduate School of Eng., 1) Dept. of Electrical Engineering 2) Dept. of Electronic Science and Eng. Katsura, Kyoto, 615-8510, Japan. a) Email: funaki@kuee.kyoto-u.ac.jp 3) University of Arkansas, Department of Electrical Engineering, 3217 Bell Engr. Center, Fayetteville, AR 72701, USA 441 0-7803-9547-6/06/$20.00 ©2006 IEEE.