Global shutter image sensor pixels having centralized charge storage regions

摘要

An image sensor may be provided with an array of image pixels formed on a substrate having front and back surfaces. Each pixel may have a photodiode that receives light through the back surface, a floating diffusion node, and a charge transfer gate. The floating diffusion node may be formed in the center of the photodiode and may be surrounded by the charge transfer gate at the front surface. The charge transfer gate may isolate the floating diffusion node from the surrounding photodiode. The pixel may include reset transistor gates, an addressing transistor gate, and a source follower transistor arranged about the periphery of the photodiode. By centering the floating diffusion node and charge transfer gate within the photodiode, the image pixels may have improved shutter efficiency and charge transfer efficiency relative to pixels having floating diffusion nodes at non-centralized locations.

主权项

1. An image sensor pixel formed on a semiconductor substrate, comprising:
a photodiode that generates charge in response to image light, wherein the photodiode extends across a lateral area of the semiconductor substrate; a floating diffusion region formed at a location on the semiconductor substrate that is substantially centered with respect to the lateral area; and a charge transfer gate that is formed within the lateral area on the semiconductor substrate, wherein the charge transfer gate is interposed between the floating diffusion region and the photodiode and configured to transfer the generated charge from the photodiode to the floating diffusion region.