Backside illumination global shutter image sensor with trench storage gate
AssigneeSemiconductor Components Industries, LLC
InventorsJohn P. Mccarten, Hung Q. Doan, Konstantin G. Korablev
Life of this patent
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Abstract
An image sensor may include an array of global shutter image pixels arranged in rows and columns. Each global shutter image pixel may include a storage gate implemented as a trench transistor. The storage gate may be at least partially covered by a corresponding backside deep trench isolation structure. The deep trench isolation structure can be filled with light-shielding material. Configured in this way, the global shutter image pixel exhibits improved global shutter efficiency.
Claims18
An image sensor, comprising:
- a substrate having a front surface and a back surface;
- a photodiode formed in the substrate;
- a charge transfer transistor coupled to the photodiode and formed in the front surface of the substrate;
- a storage gate coupled between the photodiode and the charge transfer transistor, wherein the storage gate comprises a trench transistor formed in the front surface of the substrate;
- and
- a deep trench isolation structure formed in the back surface of the substrate, wherein the deep trench isolation structure is laterally aligned with the storage gate;
- and
- wherein the photodiode has a portion that extends into a region between the storage gate and the deep trench isolation structure.
A method of manufacturing an image sensor, comprising:
- obtaining a substrate having a front surface and a back surface;
- forming a photodiode region in the substrate;
- etching a trench in the front surface of the substrate;
- implanting a potential well in a region of the substrate at least partially surrounded by the trench;
- growing a gate oxide layer in the trench;
- depositing conductive gate material into the trench;
- and
- forming a deep trench isolation structure in the back surface of the substrate, wherein the deep trench isolation structure is aligned with the trench;
- and
- wherein the photodiode region is at least partially surrounded by the deep trench isolation and has a portion that extends between the trench and the deep trench isolation structure.
An image sensor pixel, comprising:
- a substrate having an upper surface and a lower surface;
- a trench transistor formed in the upper surface;
- and
- a deep trench isolation structure formed in the lower surface, wherein the deep trench isolation structure at least partially covers the trench transistor from the lower surface;
- and
- a photodiode region at least partially laterally surrounded by the deep trench isolation structure, wherein the photodiode region has a portion that extends into a region of the substrate between the trench transistor and the deep trench isolation structure.
Dependencies are inferred from the claim text.