Low-voltage superjunction technology

The scalability of superjunction and superfield power MOSFET technologies to breakdown voltage lower than 250 V is investigated. The influence of device geometry and process architecture on the switching figures-of-merit of these relatively new classes of power switches with a breakdown voltage rating of 80 V is presented. The current flow and field distributions inside these devices are described. Using Gauss's law, the field-induced compensation of the doping density in the drift region during the blocking state of both superjunction and superfield MOSFETs is calculated from the knowledge of the lateral field distributions. It is shown that the problem associated with imperfect charge compensation at the edge of the die for a superfield effect power MOSFET structure can be avoided by using an unconventional racetrack layout design.