Pixel sensor and methods for manufacturing pixel sensor and deep trench isolation structure thereof

A method for manufacturing a deep trench isolation structure, comprising:

• forming a seed layer on a substrate;
• forming an epitaxial layer on the seed layer, a depth of the epitaxial layer being greater than 4 microns;
• etching the epitaxial layer to form one or more trenches;
• etching the seed layer exposed in the trench to remove the seed layer;
• performing a deposition process on a substrate surface area below the epitaxial layer to form a bottom insulating layer between the epitaxial layer and the substrate;
• and
• filling an oxide layer in the trench, and the oxide layer forms a deep trench isolation structure in the epitaxial layer.

A method for manufacturing a pixel sensor, comprising:

• forming a bottom insulating layer on a first type doped substrate;
• disposing an epitaxial layer on the bottom insulating layer, and the bottom insulating layer isolating the first type doped substrate and the epitaxial layer;
• forming a deep trench isolation structure in the epitaxial layer, a depth of the deep trench isolation structure being at least greater than 4 microns;
• and
• forming a photodiode in the epitaxial layer, the deep trench isolation structure being adjacent to the photodiode, the photodiode including a second type doped extension region, and a depth of the photodiode and the second type doped extension region being at least greater than 4 microns.