Patent ID: 8823095

Claim:
A MOS power transistor having a drain and a source separated by a field oxide configured for a rated voltage above 100V between said drain and said source, said MOS power transistor being at least twice as long as it is wide, comprising: a rectangular isolating trench in an edge area of the MOS power transistor preventing an electrical breakthrough when blocking the rated voltage, said rectangular isolation trench having two parallel longer trench portions along the length and two parallel shorter trench portions along the width, and defining an outer contour of said MOS power transistor; wherein the rectangular isolating trench is filled with an isolating material and a filler material between two vertical layers of the isolating material configuring the rectangular isolating trench to terminate the MOS transistor by electrical field line control to neighboring areas up to the rated voltage; the MOS power transistor having a gate electrode overlapping with length portions of the two longer trench portions of the rectangular isolation trench, and wherein a ratio of a depth to a breadth of the rectangular isolating trench is between 8:1 and 15:1.