A method for forming a deep trench isolation structure for a CMOS image sensor includes providing a trench that extends from a first side toward a second side of a semiconductor substrate. The trench has an opening on the first side and a bottom and sides. A conformal layer of B-doped oxide is deposited on the bottom and sides of the trench and is less than half a width of the trench leaving a depthwise recess in the trench. A second material is deposited on the conformal layer of B-doped oxide in the trench filling the recess in the trench to the first side. The conformal layer of B-doped oxide is annealed driving boron from the conformal layer of B-doped oxide to the semiconductor substrate forming a B-doped region as a passivation layer juxtaposed next to the conformal layer of B-doped oxide having negative fixed charges.