A semiconductor power device includes a plurality of groups of stripe-shaped gate trenches extending in a silicon region over a substrate, and a plurality of stripe-shaped sinker trenches each extending between two adjacent groups of the plurality of groups of stripe-shaped gate trenches. The plurality of stripe-shaped sinker trenches extend from a top surface of the silicon region through the silicon region and terminate within the substrate. The plurality of stripe-shaped sinker trenches are lined with an insulator along the sinker trench sidewalls so that a conductive material filling each sinker trench makes electrical contact with the substrate along the bottom of the sinker trench and makes electrical contact with an interconnect layer along the top of the sinker trench.