Image sensor

An image sensor, comprising:

• a substrate comprising a plurality of unit pixel regions, the substrate having first and second surfaces facing each other,
• wherein each of the unit pixel regions comprises:
• a plurality of floating diffusion parts spaced apart from each other in the substrate;
• a plurality of storage nodes provided in the substrate and spaced apart from the floating diffusion parts, wherein each of the storage nodes faces a corresponding one of the floating diffusion parts;
• a single transfer gate adjacent to a region between the floating diffusion parts and the storage nodes;
• and
• a plurality of photoelectric conversion parts sequentially stacked on one of the first and second surfaces, wherein each of the photoelectric conversion parts comprises a common electrode and a pixel electrode,
• the common electrode being provided at a top surface of its photoelectric conversion part,
• the pixel electrode being provided at a bottom surface of its photoelectric conversion part, and electrically connected to a corresponding one of the storage nodes,
• wherein the single transfer gate includes a first portion, which is provided on the first surface of the substrate, and a second portion which is extended from the first portion and is inserted into the substrate, and
• wherein a signal from a first one of the storage nodes to a corresponding a first one of the floating diffusion parts is simultaneously transferred with a signal from a second one of the storage nodes to a corresponding second one of the floating diffusion parts by the single transfer gate in one of the unit pixel regions.