Analysis of superjunction structure of fast switching loss IGBT with non-equivalent segmented anode NPN

Abstract

To reduce switching losses and improve the breakdown voltage of IGBTs, a novel superjunction IGBT structure with a non-equivalent segmented anode NPN transistor (NSA-SJ-IGBT) is proposed, along with a simulation study of its performance. The proposed structure incorporates a collector region embedded with a non-equivalent segmented anode NPN transistor. By optimizing the concentration and thickness of the P-type region in the NPN transistor of the NSA-SJ-IGBT, electron extraction during the turn-off process is accelerated, resulting in a significant reduction in turn-off losses. Additionally, during the turn-on process, the NSA-SJ-IGBT benefits from a more direct flow path for both electrons and holes, as well as a more uniform distribution of electron and hole densities, which facilitates faster and more efficient turn-on. Compared to the NSA-BJSJ-IGBT structure, the NSA-SJ-IGBT exhibits a reduction of approximately 38.7 % in turn-on losses at the same forward conduction voltage, while maintaining similar breakdown voltage and turn-off losses. When compared to the BJSJ-IGBT, under equivalent conditions and comparable forward conduction voltage, the NSA-SJ-IGBT demonstrates a 41 % reduction in turn-off losses, a 32 % reduction in turn-on losses, and an improvement in breakdown voltage. Furthermore, the NSA-SJ-IGBT offers significant design flexibility, enabling better optimization of the trade-off between turn-off loss and conduction voltage drop by adjusting the embedded NPN transistor, thereby enhancing overall device performance.