Band-to-Band Tunneling Injection Insulated-Gate Bipolar Transistor with a Soft Reverse-Recovery Built-In Diode

A band-to-band tunneling injection insulated-gate bipolar transistor (IGBT) featuring a tunnel junction as the collector p-n junction is proposed. The tunnel junction injects not only holes into the n-drift region by diffusion when it is forward biased but also electrons by band-to-band tunneling when it is reverse biased. Thus, the proposed device shows the output characteristics of a reverse conducting IGBT (RC-IGBT). Compared with the conventional RC-IGBT, which is prone to current concentration, the proposed device conducts current uniformly in both forward and reverse conducting states, which are favorable to the increase in conducting capability and the reduction in the reverse recovery peak current. During the reverse recovery, the electrons extracted from the drift region to the collector induce the hole injection into the drift region, which leads to the soft reverse recovery of the built-in diode. In addition, the technological ease of fabrication (no backside photolithography) is another attraction of the proposed device.