A new generation of power unipolar devices: the concept of the FLoating islands MOS transistor (FLIMOST)

In this paper, a new vertical DMOS Transistor is proposed, in which floating islands are placed in the drift region. This new structure, called “FLIMOST”, exhibits improved on-state performance when compared to the conventional VDMOST. For instance, for a breakdown voltage of 900 Volts, the performance is strongly improved in term of specific 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 FLIMOST family are determined and compared to those of the “Superjunction” MOS Transistor family: this comparison shows the strong interest of the FLIMOSFET in the 200 V-1000 V breakdown voltage range