Patent ID: 8431466

Claim:
A trench isolation method for finned semiconductor devices, the method comprising: forming, from a bulk semiconductor substrate, a first conductive fin set and a second conductive fin set, the first conductive fin set and the second conductive fin set being separated by a gap; depositing an oxide material over the first conductive fin set, the second conductive fin set, and the bulk semiconductor substrate, the oxide material forming a recess that corresponds to the gap, the recess being defined by opposing sidewalls of the oxide material; deepening the recess into the bulk semiconductor substrate to form a trench that is self-aligned with the opposing sidewalls; filling the trench with a dielectric material, and filling between adjacent conductive fins in the first conductive fin set and between adjacent conductive fins in the second conductive fin set with the dielectric material; and etching a portion of the dielectric material to expose an upper section of the first conductive fin set and an upper section of the second conductive fin set, while preserving the dielectric material in the trench, and retaining a layer of the dielectric material between and at the base of the adjacent conductive fins in each conductive fin set.