Method of forming super steep retrograde wells on finfet

A partial semiconductor structure comprising:

• a first plurality of fins comprising a first plurality of sidewalls, a layer of pure boron on one or more sidewalls of the first plurality of sidewalls, a silicon nitride liner on the layer of pure boron, and a layer of oxide between two or more fins of first plurality of fins, wherein a thickness of the layer of pure boron is less than 1 nm, and a tip of one or more fin of the first plurality of fins is exposed above a top of the layer of oxide and is not covered by the layer of pure boron;
• and
• a second plurality of fins comprising a second plurality of sidewalls, a layer of phosphosilicate glass on one or more sidewalls of the second plurality of sidewalls, a silicon nitride liner on the layer of phosphosilicate glass, and a layer of oxide between two or more fins of the second plurality of fins, wherein a tip of one or more fin of the second plurality of fins is exposed above a top of the layer of oxide and is not covered by the layer of phosphosilicate glass.