US Patent 9818649 Method and structure for FinFET isolation

A semiconductor device includes a substrate having first and second fins extending lengthwise generally along a same line; a first gate stack over the substrate and engaging the first fin; a second gate stack over the substrate and engaging the second fin; a first isolation structure disposed between the first and second fins; and spacer features on sidewalls of the first and second gate stacks and on sidewalls of an upper portion of the first isolation structure.