Back to results
US 8,796,057 B2Granted
Isolation structures for global shutter imager pixel, methods of manufacture and design structures
AssigneeInternational Business Machines Corporation
InventorsBrent A. Anderson, Mark D. Jaffe
Life of this patent
Estimating the term…
Abstract
Pixel sensor cells, e.g., CMOS optical imagers, methods of manufacturing and design structures are provided with isolation structures that prevent carrier drift to diffusion regions. The pixel sensor cell includes a photosensitive region and a gate adjacent to the photosensitive region. The pixel sensor cell further includes a diffusion region adjacent to the gate. The pixel sensor cell further includes an isolation region located below a channel region of the gate and about the photosensitive region, which prevents electrons collected in the photosensitive region to drift to the diffusion region.
Claims11
A method of forming a pixel sensor cell, comprising:
- forming a deep trench isolation structure in a substrate;
- forming a buried deep trench isolation structure in the substrate;
- forming a channel region over the buried deep trench isolation structure;
- forming a photosensitive region within a perimeter formed by the deep trench isolation structure and the buried deep trench isolation structure;
- and
- forming gates outside the perimeter,
- wherein:
- the deep trench isolation structure and the buried deep trench isolation structure form a diffusion shield surrounding an entire perimeter of a photodiode that includes the photosensitive region;
- the forming the deep trench isolation structure comprises:
- etching into the substrate to form a trench of the deep trench isolation structure;
- lining the trench of the deep trench isolation structure with an insulator;
- and
- filling the trench of the deep trench isolation structure with a conductive material;
- the forming of the buried deep trench isolation structure comprises:
- etching into the substrate to form a trench of the buried deep trench isolation structure;
- lining the trench of the buried deep trench isolation structure with the insulator;
- filling the trench of the buried deep trench isolation structure with the conductive material;
- forming a recess in the trench of the buried deep trench isolation structure by etching the conductive material in the trench of the buried deep trench isolation structure;
- removing the insulator in the recess;
- and
- capping exposed portions of the conductive material with a capping mask;
- the capping the exposed portions of the conductive material comprises forming a capping layer in the recess and directly on the exposed portions of the conductive material;
- and
- the forming the channel region over the buried deep trench isolation structure comprises forming a silicon material in the recess and directly on the capping layer.
21 more elements
A method of forming a pixel sensor cell, comprising:
- forming a deep trench isolation structure in a substrate;
- forming a buried deep trench isolation structure in the substrate;
- forming a channel region over the buried deep trench isolation structure;
- forming a photosensitive region within a perimeter formed by the deep trench isolation structure and the buried deep trench isolation structure;
- and
- forming gates outside the perimeter,
- wherein the forming the deep trench isolation structure comprises etching into the substrate to form a trench, lining the trench with an insulator and filling the trench with a conductive material;
- and
- wherein the forming of the buried deep trench isolation structure comprises:
- etching into the substrate to form a plurality of trenches;
- filling the plurality of trenches with a removable fill material;
- lining remaining portions of the trench over the removable filling material and on sidewalls with an insulator;
- etching the removable fill material within the plurality of trenches until the plurality of trenches are formed into a single trench under the substrate, with collars extending to a surface of the substrate;
- lining the single trench with additional insulator material;
- and
- filling the single trench including the collars with the conductive material.
13 more elements
A method of forming a pixel sensor cell, comprising:
- forming a deep trench isolation structure in a substrate;
- forming a buried deep trench isolation structure in the substrate;
- lining the buried deep trench isolation structure with an insulator liner material on sidewalls thereof;
- forming conductive material within the buried deep trench isolation structure over the liner material;
- forming a channel region over the buried deep trench isolation structure;
- forming a photosensitive region within a perimeter formed by the deep trench isolation structure and the buried deep trench isolation structure;
- and
- forming gates outside the perimeter,
- wherein:
- the buried deep trench isolation structure is formed below the channel region of the gates and about the photosensitive region;
- and
- the buried deep trench isolation structure extends into a P-epi substrate and a P+ substrate.
9 more elements
Dependencies are inferred from the claim text.