Trench isolation structure and method of forming trench isolation structures. The structures includes a trench in a silicon region of a substrate, the trench extending from a top surface of the substrate into the silicon region; an ion implantation stopping layer over sidewalls of the trench; a dielectric fill material filling remaining space in the trench, the dielectric fill material not including any materials found in the stopping layer; an N-type dopant species in a first region of the silicon region on a first side of the trench; the N-type dopant species in a first region of the dielectric material adjacent to the first side of the trench; a P-type dopant species in a second region of the silicon region on a second side of the trench; and the P-type dopant species in a second region of the dielectric material adjacent to the second side of the trench.