Low ON-State Voltage Optically Triggered Power Transistor for SiC Emitter Turn-OFF Thyristor

In this letter, a new optically triggered power transistor (OTPT) rated for 100-A load current is proposed. Moreover, some modifications in the base epitaxial layer are made to reduce both the ON-state voltage drop and the required optical power for the driving laser. This new structure benefits the fact that increasing the leakage current yields to a lower ON-state voltage in power semiconductor devices (PSDs). Although the proposed structure has a higher leakage current during the OFF-state, the high leakage current is blocked by a high-power low-leakage SiC thyristor that is connected in series with the proposed OTPT. Therefore, one can use the advantage of a rather leaky OTPT to further decrease the ON-state voltage. ON-state voltage drop of 0.8 V is achieved across the proposed OTPT in operating condition of 100 A and 100 °C while it is illuminated by optical power of 5 W. The proposed OTPT, respectively, features 22% and 92% improvement in the textscon-state voltage drop at optical powers of 5 and 2 W, as compared with the conventional low-leakage OTPT.