Masakiyo Sumitomo

Low loss IGBT with Partially Narrow Mesa Structure (PNM-IGBT)

A PNM (Partially Narrow Mesa) -IGBT with a fundamentally new surface is proposed for the first time. The unique gate shape looks like a “vase” and generates an extreme injection enhancement. Its performance approaches the limits of Si-IGBT. Therefore, PNM-IGBT is able to contribute to the saturation voltage reduction and the improvement of Vce(sat)-Eoff trade off. Furthermore, it can be adapted to actual conditions because of its sufficiently rugged structure.

Injection control technique for high speed switching with a double gate PNM-IGBT

We proposed a PNM-IGBT [1] that can realize performance close to the theoretical limit shown by Nakagawa, et, al [2, 3]. In that work, we confirmed PNM-IGBT can achieve a very low saturation voltage due to its great injection enhancement effect. However, it is accompanied by a slight increase in turn-off-loss. We believe that we can diminish this increase by our unique control technique. Therefore, in this paper, we propose a fundamentally new IGBT control technique. By combining this control technique and PNM-IGBT, it becomes possible to achieve both a low saturation voltage and fast switching speed. To demonstrate the above hypothesis, we have developed a double gate PNM-IGBT, and confirmed a decrease in turn-off-loss of 30% using this technique.