Image sensor

An image sensor comprising:

• a substrate comprising a first surface and a second surface opposing the first surface;
• first to fourth pixel regions in the substrate arranged in a 2×2 matrix in a plan view, wherein each of the first to fourth pixel regions comprises a photoelectric conversion region;
• a first trench isolation encircling the first to fourth pixel regions;
• a second trench isolation separating the first to fourth pixel regions from each other;
• a ground contact vertically overlapping the first and second pixel regions in the plan view and disposed in edge portions of the first to fourth pixel regions in the plan view;
• a floating diffusion region configured to receive electrons generated at the photoelectric conversion regions in the first to fourth pixel regions,
• wherein each of the first to fourth pixel regions further comprises a first vertical transfer gate extending into the substrate from the first surface, and
• wherein the floating diffusion region is disposed at a center of the 2×2 matrix in the plan view.

An image sensor comprising:

• a substrate comprising a first surface and a second surface opposing the first surface;
• first to fourth photoelectric conversion regions in the substrate arranged in a 2×2 matrix in a plan view;
• a floating diffusion region disposed in a center of the 2×2 matrix in the plan view;
• a first set of first to fourth transfer gates configured to transfer electrons generated at the first to fourth photoelectric conversion regions to the floating diffusion region;
• a first trench isolation encircling the first to fourth photoelectric conversion regions along edge portions of the first to fourth photoelectric conversion regions in the plan view;
• a second trench isolation separating the first to fourth photoelectric conversion regions from each other in the plan view;
• a first ground contact disposed in a first edge portion of the edge portions of the first to fourth photoelectric conversion regions in the plan view;
• and
• a second ground contact disposed in a second edge portion of the edge portions of the first to fourth photoelectric conversion regions in the plan view,
• wherein the first ground contact is opposite to the second ground contact along the edge portions of the first to fourth photoelectric conversion regions in the plan view.