5kV 4H-SiC SEJFET Sei-Hyung Ryu John W. Palmour Temperature dependence of On-state characteristics, and Switching characteristics of 5 kv class 4H-SiC SEJFET Katsunori Asano, Member, Toshihiko Hayashi, Member, Daisuke Takayama,Member, Yoshitaka Sugawara, Member, Sei-Hyung Ryu, Non-member, John W. Palmour, Non-member A normally-off type 5 kv class 4H-SiC JFET with low specific on-resistance, called SEJFET (Static Expansion channel JFET), has been fabricated. Its normally-off operation is realized at the temperature from RT to 600 K. A very fast switching time of the 4H-SiC SEJFET are realized. The turn-on time at RT is 20ns and the turn-off time at RT is 47ns. In this SEJFET, temperature dependences of the output characteristics and transfer characteristics are evaluated. Its specific on-resistance has a large positive temperature dependence, and its transconductance has a large negative temperature dependence. SiCJFET SEJFET Keywords: SiC, high blocking voltage, JFET, SEJFET, specific on-resistance, threshold voltage, current gain, turn on time, turn off time 1. Si Si Si Si SiC SiC Si 10 3.2 ev 4H-SiC Si 3 (1) Si FET 661-0974 3-11-20 Electric Power Engineering Research Center, The Kansai Electric Power Company 11-20, 3-Chome, Nakoji, Amagasaki 661-0974 Cree, Inc 4600 Silicon Drive, Durham, NC 27703 USA SIT SiC FET Si FET SiC FET (2) (15) 4H-SiC MOSFET 10 cm 2 /Vs (2) (4) (6) Si MOSFET 1/32 4kV 6kVSiCSIAFET (7) (8) 5 kv SEMOSFET (9) SiC JFET (10) (11) 5 kv 5.5 kv JFET SEJFET; Static Expansion channel JFET (12) (13) 3kV JFET (14) (15) SEJFET 2. 4H-SiC SEJFET 1 4H-SiC SEJFET SEJFET 2 D 125 2 2005 147
1 4H-SiC SEJFET Fig. 1. Schematic cross-sectional structure of 4H-SiC SEJFET. 2 4H-SiC SEJFET 300 K Fig. 2. Output characteristics of a fabricated 4H-SiC SEJFET at 300 K. JFET p p n p p 4H-SiC 2.7 V (12) 3. 4H-SiC SEJFET 3 1 4H-SiC SEJFET 4H-SiC SEJFET 30 /cm 2 5 10 19 cm 3 n + 4H-SiC CVD (16) 9 10 14 cm 3 45 µm p Al n p p 6.2 kv 4H-SiC pn JTE (17) 4H-SiC SEJFET 1.7 mm 1.7 mm 4.45 10 3 cm 2 1.3 3 2 4H-SiC SEJFET 2 5.1 kv 4H-SiC SEJFET V GS 0V I DS V GS 2.0 V I DS V GS =5V V DS =1V78 mωcm 2 V GS = 5V 0.29 ma 5kV 69 mωcm 2 (13) SEJFET 600 K 300 K V GS =5V 22.2 A/cm 2 = 98.8 ma/4.45 10 3 cm 2 p p 3 8 4H-SiC SEJFET 3 148 IEEJ Trans. IA, Vol.125, No.2, 2005
SiCSEJFET 3 4H-SiC SEJFET Fig. 3. Output characteristics of a fabricated 4H-SiC SEJFET at V GS = 5 V at various temperatures. 4 4H-SiC SEJFET Fig. 4. Temperature dependence of the specific onresistance of a fabricated 4H-SiC SEJFET at V GS =5V and V DS =1V. V GS =5V 4H-SiC 4 4H-SiC SEJFET Specific On-resistance V GS =5V V DS 1V 2.8 4H-SiC 4H-SiC 2.0 3.1 (18) (19) 4H-SiC SEJFET 5 4H-SiC SEJFET V DS 5V I DS V GS 6 gm gm 5 gm 2.1 5 4H-SiC SEJFET Fig. 5. Transfer characteristics of a fabricated 4H-SiC SEJFET at various temperatures. 7 Vth Vth 5 V GS 2.5 V 4.0 V I DS =0 V GS Vth Vth 500 K 8 4H-SiC SEJFET V GS 5V V DS 1V I GS 300 K 0.29 ma I GS 600 K 5.5 ma 9 4H-SiC SEJFET D 125 2 2005 149
6 4H-SiC SEJFET gm Fig. 6. Temperature dependence of the transconductances of a fabricated 4H-SiC SEJFET. 8 4H-SiC SEJFET Fig. 8. Gate current of a fabricated 4H-SiC SEJFET at elevated temperatures. 7 4H-SiC SEJFET Vth Fig. 7. Temperature dependence of the threshold voltages of a fabricated 4H-SiC SEJFET. 9 4H-SiC SEJFET Fig. 9. Temperature dependence of the current gains of a fabricated 4H-SiC SEJFET. Current gain V GS 5V I GS 300 K 343, 600 K 3.7 9 exp( 0.0153T)T 3 3 4H-SiC SEJFET 10 4H-SiC SEJFET Fig. 10. 10 Measurement circuit of the switching characteristics. 150 IEEJ Trans. IA, Vol.125, No.2, 2005
SiCSEJFET SEJFET 4. 11 4H-SiC SEJFET Fig. 11. Turn-on waveforms at room temperature of a fabricated 4H-SiC SEJFET. 4H-SiC JFET SEJFET 1 4H-SiC SEJFET 600 K 2 4H-SiC SEJFET 2.8 2.1 4 4H-SiC SEJFET 343 5 4H-SiC SEJFET 20 ns 47 ns 15 9 19 16 9 1 12 4H-SiC SEJFET Fig. 12. Turn-off waveforms at room temperature of a fabricated 4H-SiC SEJFET. 4H-SiC SEJFET 11 12 5V V DS 30 V 11 V DS I DS 20 ns 7ns 13 ns 47 ns 7ns 40 ns 1 SiC,, Vol.185, p.282 (1998) 2 S. Onda, R. Kumar, and K. Hara: SiC integrated MOSFETs, Phys. stat. sol. (a) 162, pp.369 388 (1997) 3 Y. Sugawara and K. Asano: 1.4 kv 4H-SiC UMOSFET with Low Specific On-Resistance, Proceedings of ISPSD 98, pp.119 122 (1998) 4 J. Tan, J.A. Cooper, and M.R. Melloch Jr.: High-voltage accumulationlayer UMOSFET s in 4H-SiC, IEEE Electron Device Letters, Vol.19, No.12, pp.487 489 (1998) 5 D. Peters, R. Schorner, P. Friedrichs, J. Volkl, H. Mitlehner, and D. Stephani: An 1800 V triple implanted vertical 6H-SiC MOSFET, IEEE Transact. Electron Devices, Vol.46, No.3, pp.542 545 (1990) 6 P.M. Senoy and B.J. Baliga: The planar 6H-SiC ACCUFET: A new highvoltage power MOSFET structure, IEEE Electron Device Letters, Vol.18, No.12, pp.589 591 (1997) 7 Y. Sugawara, K. Asano, R. Singh, J. Palmour, and D. Takayama: 4.5 kv novel high voltage high performance SiC-FET SIAFET, Proceedings of ISPSD 2000, pp.105 108 (2000) 8 D. Takayama, Y. Sugawara, T. Hayashi, R. Singh, J. Palmour, S. Ryu, and K. Asano: Static and Dynamic Characteristics of 4-6 kv 4H-SiC SIAFETs, Proceedings of ISPSD 01, pp.41 44 (2001) 9 Y. Sugawara, K. Asano, D. Takayama, S. Ryu, R. Singh, J. Palmour, and T. Hayashi: 5.0 kv 4H-SiC SEMOSFET with low RonS of 88 mωcm 2, Proceedings of ICSCRM2001 (2001) 10 H. Mitlehner, W. Bartsch, K.O. Dohnke, P. Rriedrichs, R. Kaltschmidt, U. Weinert, B. Weis, and D. Stephani: Dynamic characteristics of high voltage 4H-SiC vertical JFETs, Proc. of ISPSD 99, pp.339 342 (1999) 11 P. Friendrichs, H. Witlehner, K.O. Dohnke, D. Peters, R. Schorner, U. Weinert, E. Baudelot, and D. Stephani: SiC Power devices with low onresistance for fast switching applications, Proc. of ISPSD2000, pp.213 216 (2000) 12 K. Asano, Y. Sugawara, S. Ryu, R. Singh, J. Palmour, T. Hayashi, and D. Takayama: 5.5 kv Normally-off Low RonS 4H-SiC SEJFET, Proc. of ISPSD 01, pp.23 26 (2001) 13 K.Asano,Y.Sugawara,T.Hayashi,S.Ryu,R.Singh,J.Palmour,andD. Takayama: 5 kv 4H-SiC SEJFET with Low RonS of 69 mωcm 2, Proc. of ISPSD 02, pp.61 64 (2002) 14 J.H.Zhao,X.Li,K.Tone,P.Alexandrov,M.Pan,andM.Weiner: ANovel High-Voltage Normally-Off 4H-SiC Vertical JFET, Materials Science Forum Vol.389-393, pp.1223 1226 (2002) 15 J.H. Zao, K. Tone, X. Li, P. Alexandrov, L. Fursin, and M. Weiner: 3.6mWcm 2, 1726 V 4H-SiC Normally-off Trenched-and-Implanted Verti- D 125 2 2005 151
cal JFETs, Proc. of ISPSD 2003, pp.50 53 (2003) 16 O. Kordina, J.P. Bergman, A. Henry, E. Janzen, S. Savage, J. Andre, L.P. Ramberg, U. Lindefelt, W. Hermansson, and K. Bergman: A 4.5 kv 6H silicon carbide rectifier, Appl. Phys. Letter, Vol.67, pp.1561 1563 (1995) 17 Y. Sugawara and K. Asano: 6.2 kv 4H-SiC pin diode with low forward voltagedrop,materials Science Forum Vol.338 342, pp.1371 1374 (2000) 18 A. Itoh, T. Kimoto, and H. Matsunami: Efficient Power Schottky Rectifiers of 4H-SiC, Proc. of ISPSD 95, pp.101 106 (1995) 19 K. Asano, T. Hayashi, R. Saito, and Y. Sugawara: High Temperature Static and Dynamic Characteristics of 3.7 kv High Voltage 4H-SiC JBS, Proc. of ISPSD2000, pp.97 100 (2000) 1965 7 20 1991 3 4 SF 6 HVDC 8kV SiC 1970 12 9 1996 3 4 1999 SiC 1970 7 17 1996 3 4 1999 SiC 1969 MOCVD IC 1995 HVDC 8kV SiC 1998 ISPSD IEEE Sei-Hyung Ryu He was received B.S. Degree in February, 1992 from Seoul National University (Seoul, Korea), and M.S. and Ph.D. degrees in Electrical Engineering in December 1993 and in May 1997, respectively, from Purdue University, where he developed a CMOS technology in 6H-SiC for smart power applications. He continued his research in SiC devices as a Post- Doctoral Research Associate with the Wide Bandgap Research Group of Purdue University until January 1999. Since February 1999, He is with Cree, Inc., where he has been developing high performance power switching devices such as DiMOSFETs, SIAFETs, SEJFETs, SEMOSFETs, GTO s, BJT s, IGBT s, and Schottky rectifiers. John W. Palmour He is a co-founder of Cree Inc., Durham, NC, where he is the Director of Advanced Devices. He has been responsible for the development of high voltage, high temperature 4H-SiC power diodes, MOSFETs and thyristors, as well as high frequency MESFETs and SiC CMOS circuits. He is also responsible for Cree s development of microwave GaN HEMTs. Dr. Palmour received his B.S. and Ph.D. degrees in Materials Science from North Carolina State University in 1982 and 1988, respectively. He has co-authored over 165 publications in various conference proceedings and refereed journals, and is an inventor on 17 issued US patents concerning semiconducting SiC. He also serves on the Board of Directors for Cree, Inc. 152 IEEJ Trans. IA, Vol.125, No.2, 2005