Method and device for power rail in a fin type field effect transistor

A semiconductor device structure, comprising:

• semiconductor fins, disposed on a substrate, the semiconductor fins pitched at a fin pitch;
• a buried power rail in a trench on a first side of a cell, disposed in parallel with the semiconductor fins;
• and
• an isolation oxide between the semiconductor fins and on the buried power rail;
• wherein a width within the substrate of the buried power rail is greater than a minimum fin pitch and greater than a width of the buried power rail above the substrate.

A method for forming a fin type field effect transistor (finFET) device, comprising

• providing semiconductor fins on a substrate, the semiconductor fins pitched at a fin pitch;
• providing a mask, disposed over the semiconductor fins, the mask defining a plurality of openings;
• providing an isolation oxide disposed on the substrate, between the semiconductor fins;
• and
• directing an angled ion beam into a pair of the plurality openings to form a pair of trenches for a cell of the finFET device, wherein the pair of trenches are formed at the fin pitch through the isolation oxide and into the substrate beneath the isolation oxide, the angled ion beam to form portions of each trench of the pair of trenches in the substrate, wherein a width within the substrate of each trench of the pair of trenches is greater than the fin pitch and greater than a width of each trench of the pair of trenches above the substrate.