Pixel of image sensor and image sensor

A pixel of an image sensor, the pixel comprising:

• a semiconductor substrate comprising a first surface and a second surface;
• a photoelectric conversion region between the first surface and the second surface of the semiconductor substrate;
• a floating diffusion region provided in a cylindrical shape extending from the first surface of the semiconductor substrate into the semiconductor substrate;
• and
• a vertical transfer gate provided in a cylindrical shape surrounding the floating diffusion region and extending from the first surface of the semiconductor substrate to the photoelectric conversion region, the vertical transfer gate configured to form a transfer channel between the photoelectric conversion region and the floating diffusion region,
• wherein the vertical transfer gate and the floating diffusion region have a structure inclined at an angle less than 90 degrees with the first surface.

A backside illuminated (BSI) image sensor comprising:

• a pixel array comprises a plurality of pixels configured to generate a plurality of pixel signals based on incident light;
• and a signal unit configured to output image data based on the plurality of pixel signals,
• wherein at least one of the plurality of pixels comprises:
• a semiconductor substrate comprising a first surface and a second surface;
• a photoelectric conversion region between the first surface and the second surface;
• a floating diffusion region on the first surface of the semiconductor substrate and spaced apart from the photoelectric conversion region in a vertical direction;
• and
• a first vertical transfer gate in a first recess extending from the first surface of the semiconductor substrate to the photoelectric conversion region, the first vertical transfer gate configured to form a first transfer channel between the photoelectric conversion region and the floating diffusion region,
• wherein the first vertical transfer gate has a structure inclined toward a maximum voltage point of the photoelectric conversion region.