A new generation of power MOSFET based on the concept of "Floating Islands"

In this paper, a new concept called "Floating Islands diode" (FLI-diode) is proposed: the voltage handling capability of this new diode is assumed by the association of several PN junctions in series. This concept can be appl ied to any power devices (lateral. or vertical). An example of vertical pow er MOSFET based on this concept is presented here: this new structure, call ed "FLIMOSFET"', exhibits improved on-state resistance performance when com pared to the conventional VDMOSFET. For instance, for a breakdown voltage o f 900 volts, the theoretical performance are strongly improved in term of s pecific on-resistance (reduction of about 70% relative to the conventional structure and 40% relative to the silicon limit). Moreover the specific on- resistance theoretical limits of FLIMOSFET family are determined and compar ed to those of the "Superjunction" MOS Transistor family: this comparison s hows the strong interest of the FLIMOSFET in the 200 volts-1000 volts break down voltage range.