Image sensor

An image sensor comprising:

• a substrate comprising a first surface and a second surface facing the first surface of the substrate;
• a first photodiode(PD) located in a first region of the substrate;
• a second PD located in a second region of the substrate;
• and
• a first isolation layer between the first PD and the second PD,
• wherein an area of the second region in a plan view is smaller than an area of the first region in the plan view,
• wherein the first isolation layer is in contact with the first surface of the substrate and the second surface of the substrate,
• wherein the second region is disposed adjacent to the first region in a plan view, and
• wherein the image sensor is configured to receive light through the second surface.

An image sensor comprising:

• a substrate comprising a first surface and a second surface facing the first surface of the substrate;
• a first photodiode(PD) located in a first region of the substrate;
• a second PD located in a second region of the substrate;
• a first floating diffusion region (FD);
• a second FD;
• a first transfer gate configured to transfer photocharges generated by the first PD to the first FD;
• a second transfer gate configured to transfer photocharges generated by the second PD to the second FD;
• and
• an isolation layer between the first PD and the second PD,
• wherein an area of the second region in a plan view is smaller than an area of the first region in the plan view,
• wherein the isolation layer is in contact with the first surface of the substrate and the second surface of the substrate,
• wherein each of the first transfer gate and the second transfer gate extends into the substrate,
• wherein the second region is disposed adjacent to the first region in a plan view, and
• wherein the image sensor is configured to receive light through the second surface.