US Patent 9559014 Self-aligned punch through stopper liner for bulk FinFET

A technique relates to forming a self-aligning field effect transistor. A starting punch through stopper comprising a substrate having a plurality of fins patterned thereon, an n-type field effect transistor (NFET) region, a p-type field effect transistor (PFET) region, and a center region having a boundary defect at the interface of the NFET region and the PFET region is first provided. The field effect transistor is then masked to mask the NFET region and the PFET region such that the center region is exposed. A center boundary region is then formed by etching the center region to remove the boundary defect.