Materials Science Forum, Vol.457-460, 1169-1172, 2004
A high voltage (1570V) 4H-SiC bipolar Darlington with current gain beta > 640 and tested in a half-bridge inverter up to 20A at V-Bus=900V
This paper reports the design, fabrication and characterization of a 4H-SiC bipolar Darlington transistor with both high common emitter current gain and high blocking voltage. The driving and output transistors were and fabricated on the same chip with a 12mum, 8.5x10(15)cm(-3) doped drift layer. The Darlington's driving transistor was capable of 1,600V and 5.3A with a maximum DC current gain beta(1)=26 at a collector current I-C1=3.12A (J(C1)=260A/cm(2)) and V-CE1=4.2V, and a specific on-resistance (R-SP_(ON)) of 12.2mOmega(.)cm(2) for currents up to I-C1=3.65A (J(C1)=304A/cm(2)) and V-CE1=3.7V. The output transistor can handle over 23A and a blocking voltage higher than 1600V with a peak DC current gain beta(2)=22.3 at I-C2=15.7A (J(C2)=262A/cm(2)) and V-CE2=4.54V, and an R-SP_(ON) of 16.7mOmega(.)cm(2) for currents up to I-C2=18A (J(C2)=300A/cm(2)) and V-CE2=4.1V. The maximum AC current gain of the hybrid BJT Darlington at room temperature was >640. The DC current gain at room temperature was found to increase with the collector current, up to 462 at I-C=13.9A (J(C2)similar to232A/cm(2)) and V-CE2=10.6V, limited only by the measurement instrument. The Darlington can block voltages up to 1571V, conduct an I-C of 14A at V-F=7.7V and has a differential R-SP_(ON) of 16.7mOmega(.)cm(2) at J(C2) up to over 240A/cm(2) (I-C=14.4A). Inductively-loaded half-bridge inverter switching is also reported at 900V-20A.