Poly flanked VDMOS (PFVDMOS): a superior technology for superjunction devices

A novel VDMOS structure, named poly flanked VDMOS (PFVDMOS), is proposed for the first time to provide a better performance and process technology for superjunction MOSFET devices. The structure contains a thin oxide barrier to eliminate the existing p-n lateral interdiffusion problem, thus both the n-epi and p poly column widths can be reduced to a minimum. This reduction in column width enables the device to have a much higher n-epi doping concentration. In a sense, it leads to an optimal reduction in on-state resistance compared to other existing structures for the same voltage rating.