A pixel cell includes a photodiode buried beneath a first side of semiconductor material and coupled to photogenerate image charge in response to incident light. A transfer gate is disposed over the photodiode and includes a vertical transfer gate portion extending a first distance from the first side into the semiconductor material. A floating diffusion region is disposed in the semiconductor material proximate to the transfer gate and is coupled to transfer the image charge from the photodiode toward the first side of the semiconductor material and into the floating diffusion region in response to a transfer control signal. A first pixel transistor having a first gate is disposed over the photodiode proximate to the first side of the semiconductor material. The first gate has a ring structure laterally surrounding the floating diffusion region and the transfer gate at the first side of the semiconductor material.