Patent ID: 7977745

Claim:
A power metal-oxide-semiconductor field effect transistor (MOSFET) cell comprising: a semiconductor substrate having first and second main surfaces opposite to each other; a first electrode disposed on the first main surface of the semiconductor substrate; a voltage sustaining layer formed on the second main surface of the semiconductor substrate, the voltage sustaining layer including a first region of a first conductivity type extending to the second main surface of the semiconductor substrate and a second region of a second conductivity type extending to the second main surface of the semiconductor substrate, the second conductivity type being opposite to the first conductivity type, the voltage sustaining layer being surrounded by a dielectric region extending to the second main surface of the semiconductor substrate; a highly doped active zone of the first conductivity type formed in the voltage sustaining layer opposite the semiconductor substrate, the highly doped active zone having a striped shape with a generally central aperture and a channel region being generally centrally located within the central aperture, the voltage sustaining layer including the channel region; a stripe-shaped terminal region of the second conductivity type disposed in the voltage sustaining layer proximate the highly doped active zone, the stripe-shaped terminal region having a central aperture; and an extension region disposed in the voltage sustaining region at least partially within the central aperture of the highly doped active zone.