Image sensor pixel cell with switched deep trench isolation structure

摘要

A pixel cell includes a photodiode disposed in an epitaxial layer in a first region of semiconductor material. A floating diffusion is disposed in a well region disposed in the epitaxial layer in the first region. A transfer transistor is disposed in the first region and coupled between the photodiode and the floating diffusion to selectively transfer image charge from the photodiode to the floating diffusion. A deep trench isolation (DTI) structure lined with a dielectric layer inside the DTI structure is disposed in the semiconductor material isolates the first region on one side of the DTI structure from a second region of the semiconductor material on an other side of the DTI structure. Doped semiconductor material inside the DTI structure is selectively coupled to a readout pulse voltage in response to the transfer transistor selectively transferring the image charge from the photodiode to the floating diffusion.

主权项

1. A pixel cell, comprising:
a photodiode disposed in an epitaxial layer in a first region of semiconductor material to accumulate image charge; a floating diffusion disposed in a well region disposed in the epitaxial layer in the first region of the semiconductor material; a transfer transistor disposed in the first region of the semiconductor material and coupled between the photodiode and the floating diffusion to selectively transfer the image charge from the photodiode to the floating diffusion; a deep trench isolation (DTI) structure disposed in the semiconductor material, wherein the DTI structure isolates the first region of the semiconductor material on one side of the DTI structure from a second region of the semiconductor material on an other side of the DTI structure, wherein the DTI structure includes:
a dielectric layer lining an inside surface of the DTI structure; anddoped semiconductor material disposed over the dielectric layer inside the DTI structure, wherein the doped semiconductor material disposed inside the DTI structure is selectively coupled to a readout pulse voltage in response to the transfer transistor selectively transferring the image charge from the photodiode to the floating diffusion.