Method of fabricating fill factor enhancement for image sensor

An image sensor includes a plurality of photodiodes disposed in a semiconductor material and a plurality of isolation structures disposed between individual photodiodes in the plurality of photodiodes. The plurality of isolation structures electrically isolate individual photodiodes in the plurality of photodiodes. A plurality of transistors are disposed proximate to the plurality of photodiodes and include a reset transistor, an amplifier transistor, and a row select transistor. An active region and a gate electrode of at least one transistor in the plurality of transistors are vertically aligned with an isolation structure in the plurality of isolation structures.