Image sensors having separation structures

An image sensor, comprising:

• an insulating pattern disposed on a semiconductor substrate and having an opening;
• a through hole passing through the semiconductor substrate;
• a through electrode disposed in the through hole;
• a color filter disposed in the opening of the insulating pattern;
• an antireflective layer disposed between the insulating pattern and the semiconductor substrate and between the color filter and the semiconductor substrate;
• a capping insulating layer disposed on the color filter;
• a contact plug passing through the insulating pattern and the antireflective layer and electrically connected to the through hole;
• an electrode disposed on the capping insulating layer;
• a separation structure surrounding a side surface of the electrode;
• and
• a photoelectric layer disposed on the electrode and the separation structure,
• wherein the separation structure has an upper surface recessed in a direction toward the semiconductor substrate, and
• wherein the upper surface of the separation structure extends toward the semiconductor substrate from an upper surface of the electrode.

An image sensor, comprising:

• a semiconductor substrate having a first surface and a second surface opposing each other;
• an insulating pattern disposed on the second surface of a semiconductor substrate and having a first opening;
• a photodiode disposed in the semiconductor substrate;
• a through hole passing through the semiconductor substrate;
• a through electrode disposed in the through hole;
• a color filter disposed in the first opening of the insulating pattern;
• a contact plug passing through the insulating pattern;
• a capping insulating layer disposed on the color filter;
• a separation structure having a second opening overlapping the capping insulating layer and the contact plug;
• a first electrode disposed in the second opening of the separation structure;
• and
• a photoelectric layer disposed on the first electrode,
• wherein the separation structure includes a first insulating layer and a second insulating layer formed of different materials and stacked sequentially, and
• wherein an interface between the first insulating layer and the second insulating layer is disposed at a same distance from the second surface of the semiconductor substrate as at least a portion of the first electrode.