Analysis of Superjunction MOSFET (CoolMOSTM) Concept Limitations—Part II: Simulations

The CoolMOS^TM (Infineon Technologies AG, Munich, Germany) has been regarded as a device that alleviates high-voltage limitations of unipolar power devices. However, although the theoretical considerations seem to confirm this possibility, this expectation has not been fulfilled to date. It appears that there are some limitations in the CoolMOS^TM concept, and the paper deals with their identification. Part I concentrated on the theory of high-voltage superjunction and its implementation into a power VDMOS transistor, which resulted in the CoolMOS^TM structure. This part is aimed at the physical and technological limitations that have been identified, taking advantage of numerical investigations of CoolMOS^TM structures developed on the basis of a typical VDMOS one.