Solid-state image sensor

A solid-state image sensor having a plurality of pixels, each pixel comprising:

• an impurity layer positioned substantially at a surface of a semiconductor substrate, and formed by doping the substrate with an impurity;
• a photoelectric converting layer positioned directly beneath the impurity layer within the substrate, and generating a signal charge according to an amount of light received;
• a read out region that is positioned within the substrate so as to be apart from the impurity layer and photoelectric converting layer, and to which the generated signal charge is transferred;
• and
• a gate electrode disposed on the substrate so as to cover at least part of the substrate between the impurity layer and read out region, and controlling the transfer of the signal charge from the photoelectric converting layer to the read out region, wherein
• the impurity layer includes a portion adjoining a portion of the substrate directly beneath the gate electrode, the adjoining portion includes a plurality of sub-portions aligned along a width direction of a gate that is orthogonal to a transfer direction of the signal charge and a thickness direction of the substrate, and an impurity density is lower in a sub-portion including a center of the adjoining portion than in the other sub-portions.