Image sensor including a pixel separation region having a reduced dark level

An image sensor comprising:

• a substrate having a first surface and a second surface opposite to each other, and having a pixel separation recess extending from the first surface to the second surface;
• a plurality of photo-sensing elements in the substrate;
• and
• a pixel separation region filling the pixel separation recess, and surrounding at least a portion of each of the plurality of photo-sensing elements, the pixel separation region having a narrow region between sides of adjacent photo-sensing elements facing each other from among the plurality of photo-sensing elements, and a wide region between edges of the adjacent photo-sensing elements facing each other, and the pixel separation region including,
• a plurality of first insulating layers covering an inner wall of the pixel separation recess, and spaced apart from each other and surrounding at least one of the plurality of photo-sensing elements,
• a plurality of first conductive layers spaced apart from each other and covering at least a portion of a side surface of each of the plurality of first insulating layers within the pixel separation recess,
• a second insulating layer covering a portion of side surfaces of the plurality of first conductive layers within an inner space defined by the plurality of first conductive layers within the pixel separation recess, and
• a second conductive layer covering the plurality of first conductive layers and the second insulating layer within the inner space defined by the plurality of first conductive layers within the pixel separation recess, and the second conductive layer including,
• a connection portion adjacent to the first surface of the substrate and electrically connecting at least some first conductive layers spaced apart from each other from among the plurality of first conductive layers, and
• an extension portion extending in a vertical direction toward the second surface of the substrate from the connection portion and spaced apart from the plurality of first conductive layers with the second insulating layer therebetween.

An image sensor comprising:

• a substrate having a first surface and a second surface opposite to each other, and having a pixel separation recess extending from the first surface to the second surface;
• a plurality of photo-sensing elements in the substrate;
• and
• a pixel separation region filling the pixel separation recess, and surrounding at least a portion of each of the plurality of photo-sensing elements, the pixel separation region having a narrow region between sides of adjacent photo-sensing elements facing each other from among the plurality of photo-sensing elements, and a wide region between edges of the adjacent photo-sensing elements facing each other, and the pixel separation region including,
• a plurality of first insulating layers covering an inner wall of the pixel separation recess, and spaced apart from each other and surrounding at least one of the plurality of photo-sensing elements,
• a plurality of first conductive layers spaced apart from each other and covering at least a portion of a side surface of each of the plurality of first insulating layers within the pixel separation recess,
• a second insulating layer covering a side surface of the plurality of first conductive layers within an inner space defined by the plurality of first conductive layers within the pixel separation recess, and
• a second conductive layer covering the plurality of first conductive layers and the second insulating layer within the inner space defined by the plurality of first conductive layers within the pixel separation recess, the second conductive layer being in the wide region of the pixel separation region and not in the narrow region of the pixel separation region, and the second conductive layer including,
• a connection portion adjacent to the first surface of the substrate and electrically connecting at least some first conductive layers spaced apart from each other from among the plurality of first conductive layers, and
• an extension portion extending in a vertical direction from the connection portion to the second surface of the substrate and spaced apart from the plurality of first conductive layers with the second insulating layer therebetween.