SiC di/dt. High di/dt Switching Characteristics of a SiC Schottky Barrier Diode. Kazuto Takao, Member, Tsutomu Yatsuo, Member, Kazuo Arai, Non-member

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1 SiC di/dt High di/dt Switching Characteristics of a SiC Schottky Barrier Diode Kazuto Takao, Member, Tsutomu Yatsuo, Member, Kazuo Arai, Non-member High di/dt switching characteristics of a commercially available silicon carbide schottky barrier diode (SiC-SBD) has been experimentally evaluated in the various di/dt values of 300 A/µs to 2500 A/µs range. Diode voltage waveforms, diode current waveforms, diode stored charges, and diode turn-off losses have been theoretically analyzed. The stored charge and the diode turn-off loss are independent ofthe forward current value, thedi/dt value, and the junction temperature. It is shown that the switching behavior of the SiC-SBD can be expressed a simple variable capacitor, the capacitance of which depends on the reverse bias voltage. The switching characteristics of the SiC-SBD also have been compared to those of a commercially available ultra-fast silicon pn diode (Si-PND). The SiC-SBD has extremely low reverse current and low stored charge compared to those of the Si-PND. The SiC-SBD can reduce the IGBT turn-on loss compared to the Si-PND especially in the high di/dt operation. pn di/dt Keywords: silicon carbide schottky barrier diode, silicon pn diode, high di/dt switching characteristics, junction capacitance (1) (2) W/cm 3 (3) Si Si Si SiCSi National Institute of Advanced Industrial Science and Technology, Power Electronics Research Center AIST Tsukuba Central 2, Tsukuba Si 2 SiC Si SiC (4) (5) V 1200 V 4A 20A SiC SiC- SBD (6) (7) SiC-SBD Si-pn Si-PND (6) (7) di/dt SiC 2MHz 1MW 50 W/cm 3 (8) di/dt Si-PND di/dt L di/dt D

2 SiC-SBD (6) (7) 10 A di/dt 1000 A/µs di/dt SiC-SBD di/dt SiC-SBD di/dt = 300 A/µs 2500 A/µs SiC-SBD SiC-SBD Si-PND SiC-SBD Si-PND SiC-SBD IGBT 2. SiC-SBD SDP06S60 SiC-SBD 6A 600 V Si-PND HFA08TB60 Si-PND 8A 600 V TO SiC-SBD 1 C f L Load 80 µf 470 µh IGBT IXYS IXGH40N60C L S IGBT di/dt IGBT L S IGBT V CE Lecroy PPE2 kv I diode Pearson SiC-SBD 2877 Si-PND 2878 V diode Lecroy DXC 5100 Lecroy DA1855A Lecroy wavepro 950 I F 6A 12 A di/dt 300 A/µs 2500 A/µs C f V CC 300 VT j 25 C 150 C I F di/dt R G IGBT T j 150 C 1 Table 1. Si-PND. SiC-SBD Si-PND Basic characteristics of the SiC-SBD and the Fig Schematic diagram of the experimental circuit. 918 IEEJ Trans. IA, Vol.124, No.9, 2004

3 SiC SiC-SBD I diode V diode V CE I F = 6A di/dt = 395 A/µs 1980 A/µs T j = 25 C I diode 1.0A di/dt = 395 A/µs 3.6A di/dt = 1980 A/µs di/dt V diode V CE di/dt dv/dt 3 Si-PND I diode, V diode, V CE I F = 6A di/dt = 437 A/µs 1640 A/µs T j = 25 C I diode I RRM 5.6A di/dt = 437 A/µs 19 A di/dt = 1640 A/µs SiC-SBD 5 t rr di/dt di/dt = 437 A/µs di/dt = 1640 A/µs V diode 300 V 70 V L S di/dt Si-PND di/dt I RRM SiC-SBD 2 C SBD I diode C SBD L S V diode I diode dv diode I diode = C SBD (1) dt (1) I diode V diode di/dt I diode C SBD SiC-SBD C SBD di/dt I diode V diode C SBD L S SiC Si SiC Si 2 SiC-SBD IGBT T j = 25 C Fig. 2. Waveforms of the turn off current and voltage of the SiC-SBD and the turn on voltage of the IGBT (T j = 25 C). 3 Si-PND IGBT T j = 25 C Fig. 3. Waveforms of the turn off current and voltage of the Si-PND and the turn on voltage of the IGBT (T j = 25 C). D

4 (9) SiC Si I diode Si-PND SiC-SBD I diode V diode V CE T j = 25 C 150 C I F = 6A di/dt = 2000 A/µs T j = 25 C T j = 150 C SiC-SBD 5 Si-PND I diode, V diode,v CE T j = 25 C 150 C I F = 6A,di/dt = 2000 A/µs T j 150 C I RRM t rr Si-PND T j = 150 C T j = 25 C V diode L S di/dt T j = 25 C 70 V T j = 150 C 50 V Q C Q rr E diode IGBT E IGBT Si-PND Q rr E diode 2 SiC-SBD I diode V diode SiC-SBD Q C Si-PND Q rr E diode 1 Q C SiC-SBD I diode I diode = 0 t 1 V diode = V CC t 2 SiC-SBD E diode V diode I diode t 1 t 2 7 Q C Q rr di/dt 8 E diode di/dt 7 8 Si-PND Q rr E diode di/dt I F T j SiC-SBD Q C E diode di/dt I F T j SiC-SBD Q C E diode Si-PND Q rr E diode 2 4 I diode V diode 7 8 Q C E diode Q C E diode C SBD 4 SiC-SBD IGBT T j = 25 C 150 C Fig. 4. Comparison of waveforms of the turn off current and voltage of the SiC-SBD and the turn on voltage of the IGBT at T j = 25 C and 150 C. 5 Si-PND IGBT T j = 25 C 150 C Fig. 5. Comparison of waveforms of the turn off current and voltage of the Si-PND and the turn on voltage of the IGBT at T j = 25 C and 150 C. 920 IEEJ Trans. IA, Vol.124, No.9, 2004

5 SiC 6 SiC-SBD Si-PND IGBT Fig. 6. Definitions of turn off characteristics of 1 the SiC-SBD, 2 thesi-pnd, and 3 a turn on characteristics of the IGBT. 9 SiC-SBD C V Q C E diode Fig. 9. C V characteristic of the SiC-SBD and comparisons of Q C and E diode between calculated values and measured values. 7 SiC-SBD Q C Si-PND Q rr di/dt Fig. 7. Dependences of di/dt of Q C of the SiC-SBD and Q rr of the Si-PND. 8 SiC-SBD Si-PND E diode di/dt Fig. 8. Dependences of di/dt of E diode of the SiC-SBD and the Si-PND. SiC-SBD C V 7 8 Q C E diode Q C E diode = V CC 9 SiC-SBD C V C Q C E diode SiC-SBD V diode I diode Q C E diode C V C V Q C E diode C SBD Q C = C SBD (V R )dv R (2) E diode = V R dq C (3) V R SiC-SBD Q C E diode SiC-SBD Q C E diode C SBD SiC-SBD Q C E diode I F di/dt C V (2) (3) Si-PND E diode SiC-SBD E diode C SBD SiC-SBD 3 4 IGBT 10 IGBT E IGBT di/dt E IGBT 6 3 V CE I F 10 % V CE V CC 5% Si-PND SiC-SBD di/dt E IGBT di/dt E IGBT Si-PND T j E IGBT SiC-SBD D

6 3 2 Si-PND T j I RRM t rr SiC-SBD T j 3 5 SiC-SBD E IGBT 10 SiC-SBD E IGBT 11 di/dt Si-PND E IGBT E IGBT (Si-PND) SiC-SBD E IGBT E IGBT (SiC-SBD) % di/dt = 400 A/µs T j = 150 C SiC-SBD E IGBT 45% di/dt T j Si-PND di/dt > 1000 A/µs E diode 11 di/dt > 1000 A/µs SiC-SBD E diode SiC-SBD di/dt > 1000 A/µs di/dt E IGBT 10 E IGBT di/dt Fig. 10. Dependences of di/dt of E IGBT. 4. SiC-SBD 600 V 6A di/dt = 300 A/µs 2500 A/µs Si-PND 1 SiC-SBD Q C E diode SiC-SBD SiC-SBD 2 SiC-SBD Q C E diode I F di/dt C V 3 SiC-SBD 4 SiC-SBD E IGBT Si-PND 45% I F = 6A T j = 150 C di/dt di/dt Si-IGBT SiC-SBD Si-IGBT SiC-SBD di/dt SiC-SBD di/dt E IGBT (Si-PND) E IGBT (SiC-SBD) Fig. 11. Ratios of E IGBT (Si-PND) and E IGBT (SiC- SBD). 1 E. Masada: Power Electronics in Industrial Strategy for Modern Society, PCC-Osaka 2002 (2002) 2 (2002) 3 H. Ohashi: Recent Power Devices Trend, J. IEE Japan, Vol.122, No.3, 922 IEEJ Trans. IA, Vol.124, No.9, 2004

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