An IGBT and MOSFET gated SiC bipolar junction transistor

A high voltage 4H-SiC bipolar junction transistor (BJT) has been developed with 16 A, 600 V rating. This paper presents a new base drive structure for the SiC BJT for inverter application. The driver consists of one IGBT and one MOSFET to help turn-on and turn-off of the SiC BJT transistor in a Darlington like configuration. Instead of using conventional proportional current driven method for optimal driving bipolar transistor, the proposed base drive method can adaptively drive SiC BJT at near-saturated condition based on voltage balance of V/sub be/ and V/sub ce/. The IGBT and MOSFET gated transistor structure (IMGT) can significantly improve BJT switching behavior. Basic design principle is presented with simulation results. The proposed IMGT driver scheme is also verified by experimental results for both Si and SiC BJT. With the proposed driver scheme, the SiC BJT have the turn-on time of less than 0.5 /spl mu/s and turn-off time of less than 0.2 /spl mu/s under test condition of 300 V 15 A. Further work still needed for reducing conduction loss of SiC BJT.