Effects of On-State Snap-back Characteristics on the Current Sharing of Parallel RC-IGBTs

Reverse Conducting RC-IGBTs are in continuous development for a wide range of voltage classes targeting different power electronics applications. One of the main challenges faced in the design of RC-IGBTs is the on-state snap-back characteristics. Hence, different collector short design concepts have been investigated in order to reduce or eliminate this type of behavior. All previous investigations are based on the assumption that a negative differential resistance zone in the IV output characteristics could lead to failure events when devices are operated in parallel. Some devices might not turn-on during switching transients under real operational conditions leading to very high current densities in the conducting devices. In this paper, the effects of the snap-back characteristics on the switching behavior of parallel RC-IGBTs is presented with the aid of TCAD simulations of 1200V RC-IGBT models. Furthermore, the paper will provide analysis of the current mis-sharing at device and circuit levels.