IMAGE SENSOR PIXELS WITH SELF-ALIGNED LATERAL ANTI-BLOOMING STRUCTURES

摘要

Pixels for solid-state CMOS image sensor arrays may be provided that have a lateral blooming control structure incorporated in them. The lateral blooming control structure is built as a separate structure from the charge transfer gate and it is fabricated in a self-aligned manner, which is particularly suitable for incorporating into small size pixels. The blooming control structure can be used for backside or for front side illuminated image sensors. When the lateral blooming control structure is provided with a separate bias means, it may also be used for the complete or partial charge removal from the photodiode and thus used in pixels that are designed for global shutter operation.

主权项

1. An image sensor pixel in an image sensor having a silicon substrate and an interconnect stack formed on a surface of the silicon substrate, wherein the interconnect stack comprises a plurality of oxide layers, the image sensor pixel comprising:
a photodiode formed in the surface of the silicon substrate; a transfer gate formed on the surface of the silicon substrate, wherein the transfer gate is configured to transfer charge from the photodiode to a floating diffusion; a blooming control structure, wherein the blooming control structure is configured to remove overflow charge from the photodiode and wherein the blooming control structure is separate from the transfer gate; and a conductive contact material in the interconnect stack that provides a bias voltage to the blooming control structure, wherein the conductive contact material is at least partially surrounded by spacer structures that align the conductive contact material with the blooming control structure.