IC WITH FLOATING BURIED LAYER RING FOR ISOLATION OF EMBEDDED ISLANDS

An integrated circuit (IC) includes a substrate having a p-type semiconductor surface. A first nwell includes an area surrounding a first plurality of semiconductor devices formed in the semiconductor surface having a first n-buried layer (NBL) thereunder. A vertical diode formed in the semiconductor surface surrounds the first nwell including a pwell on top of a floating NBL ring. A second nwell formed in the semiconductor surface includes an area surrounding the floating NBL ring and surrounds a second plurality of semiconductor devices having a second NBL thereunder.