Photodetection device and photodetection system

A photodetection device comprising:

• a substrate having a first surface and a second surface which is opposite to the first surface;
• a first semiconductor region of a first conductivity type including a majority carrier of a polarity of a signal charge, the first semiconductor region being arranged in a first depth of the substrate;
• a second semiconductor region of a second conductivity type having different conductivity from the first conductivity type, the second semiconductor region being arranged in a second depth greater than the first depth from the first surface;
• and
• a trench structure with polysilicon formed in the substrate from the first surface toward the second surface, the trench structure including a first trench structure portion and a second trench structure portion,
• wherein the first semiconductor region is arranged between the first trench structure portion and the second trench structure portion in a cross section passing through the first semiconductor region and the second semiconductor region,
• wherein a semiconductor region of the second conductivity type is arranged between the first trench structure portion and the second surface and between the second trench structure portion and the second surface in the cross section, and
• wherein a third semiconductor region of the first conductivity type is arranged between an end portion of the first trench structure portion and an end portion of the second trench structure portion.