Abstract: An image sensor includes a substrate including a first face and a second face, the second face being opposite the first face in a first direction; a photoelectric conversion area disposed in the substrate; an active area disposed in the substrate and on the photoelectric conversion area; an element isolation pattern extending from the first face of the substrate into the substrate and defining the active area; and a transfer gate electrode including: a first portion extending from the first face of the substrate and extending through the element isolation pattern; and a second portion disposed on the active area, wherein the first portion extends through a bottom face of the element isolation pattern, wherein a vertical level of a bottom face of the first portion is lower than a vertical level of the bottom face of the element isolation pattern.