Patent ID: 7265415

Claim:
A trench MOS-gated transistor comprising: a first region of a first conductivity type; a well region of a second conductivity type forming a pn junction with the first region, the well region having a flat bottom portion and a portion extending deeper than the flat bottom portion, wherein the deeper portion of the well region, at its deepest point, is about 0.2-0.4 μm deeper than the flat bottom portion; a gate trench extending into the well region; and channel regions in the well region along outer sidewalls of the gate trench, wherein a first bottom portion of the gate trench terminates within the first region and a second bottom portion of the gate trench terminates within the deeper portion of the well region such that when the transistor is in an on state the deeper portion of the well region prevents a current from flowing through those channel region portions located directly above the deeper portion of the well region.