Solid-state image pickup device, manufacturing method, and electronic apparatus

A light detecting device, comprising:

• a photoelectric conversion region disposed in a semiconductor substrate;
• a floating diffusion region disposed in the semiconductor substrate, wherein the floating diffusion region includes a first region and a second region in a cross-sectional view;
• and
• a gate electrode of a transfer transistor, wherein at least a part of the gate electrode of the transfer transistor is embedded in the semiconductor substrate and disposed between the first region and the second region of the floating diffusion region in the cross-sectional view,
• wherein the gate electrode of the transfer transistor is entirely surrounded by the floating diffusion region in a plan view.

An electronic apparatus, comprising:

• an imaging device including:
• a photoelectric conversion region disposed in a semiconductor substrate;
• a floating diffusion region disposed in the semiconductor substrate, wherein the floating diffusion region includes a first region and a second region in a cross-sectional view;
• and
• a gate electrode of a transfer transistor, wherein at least a part of the gate electrode of the transfer transistor is embedded in the semiconductor substrate and disposed between the first region and the second region of the floating diffusion region in the cross-sectional view,
• wherein the gate electrode of the transfer transistor is entirely surrounded by the floating diffusion region in a plan view.

A manufacturing method, comprising:

• forming a photoelectric conversion region in a semiconductor substrate;
• forming a floating diffusion region in the semiconductor substrate, wherein the floating diffusion region includes a first region and a second region in a cross-sectional view;
• and
• forming a gate electrode of a transfer transistor, wherein at least a part of the gate electrode of the transfer transistor is embedded in the semiconductor substrate and disposed between the first region and the second region in the cross-sectional view,
• wherein the gate electrode of the transfer transistor is entirely surrounded by the floating diffusion region in a plan view.