CMOS imaging array with improved noise characteristics

摘要

A pixel cell and imaging arrays using the same are disclosed. The pixel cell includes a photodiode that is connected to a floating diffusion node by a transfer gate that couples the photodiode to the floating diffusion node in response to a first gate signal. A shielding electrode shields the floating diffusion node from the first gate signal. An output stage generates a signal related to a charge on the floating diffusion node. In one aspect of the invention, the photodiode is connected to the floating diffusion node by a buried channel, and the shielding electrode includes an electrode overlying the channel and positioned between the transfer gate and the floating diffusion node. The shielding electrode is held at a potential that prevents charge from accumulating under the shielding electrode when the floating diffusion is at the second potential.

主权项

1. A pixel cell comprising:
a photodiode; a floating diffusion node; a transfer gate that couples said photodiode to said floating diffusion node in response to a first gate signal; a shielding electrode that shields said floating diffusion node from said first gate signal; and an output stage that generates a signal related to a charge on said floating diffusion node, said shielding electrode being held at a constant potential while said transfer gate couples said photodiode to said floating diffusion node.