Patent ID: 7709890

Claim:
An insulated gate semiconductor device comprising: a semiconductor substrate of a first general conductivity type; a semiconductor layer of the first general conductivity type disposed on the semiconductor substrate; a first channel region of a second general conductivity type formed in the semiconductor layer; a second channel region of the second general conductivity type formed in the semiconductor layer; a first operation part comprising the first channel region and a plurality of first transistors each comprising a portion of the first channel region, the first transistors comprising corresponding trenches formed in the first channel region; a second operation part comprising the second channel region and a plurality of second transistors each comprising a portion of the second channel region, the second operation part being smaller than the first operation part, the second transistors comprising corresponding trenches formed in the second channel region; and an isolation region surrounding the second operation part and penetrating into the semiconductor layer and physically in contact with neither the first channel region nor the second channel region, wherein the isolation region penetrates deeper into the semiconductor layer than the trenches of the first and second transistors.