Semiconductor Power Device Having a Top-side Drain Using a Sinker Trench

A semiconductor power device includes a plurality of groups of stripe-shaped trenches extending in a silicon region over a substrate, and a contiguous sinker trench completely surrounding each group of the plurality of stripe-shaped trenches so as to isolate the plurality of groups of stripe-shaped trenches from one another. The contiguous sinker trench extends from a top surface of the silicon region through the silicon region and terminates within the substrate. The contiguous sinker trench is lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the contiguous sinker trench makes electrical contact with the substrate along the bottom of the contiguous sinker trench and makes electrical contact with an interconnect layer along the top of the contiguous sinker trench.