Patent ID: 8710561

Claim:
A pixel structure of a solid-state image sensor employing a charge sorting method that distributes electrons generated by photoelectric conversion to perform charge storage, said structure comprising: a photodiode that generates electrons by photoelectric conversion; a plurality of charge-storage sections that store electrons generated in said photodiode; and a gate structure that is arranged between said photodiode and said charge-storage sections and controls transfer of electrons generated in said photodiode to said plurality of the charge- storage sections, wherein said gate structure is made up of three stages of gates, said three stages of gates have: a first-stage gate that is arranged adjacent to said photodiode on the rear stage of the photodiode and controls read-out of electrons generated in said photodiode; a second-stage gate that is adjacent to said first-stage gate on the rear stage of the gate at a predetermined gap and controls moving of electrons read out by the readout control of said first-stage gate to said plurality of the charge-storage sections; and a third-stage gate constituted of a plurality of distribution gates that are adjacent to said second-stage gate on the rear stage of the gate at a predetermined gap, severally arranged corresponding to said plurality of the charge-storage sections, and perform control of distributing the electrons moved by the movement control of said second-stage gate severally to said plurality of the charge-storage sections, wherein said photodiode comprises a P-type impurity middle-concentration doped region having a shape in planar view of a square region from which a trapezoid is cut out and having an edge positioned adjacent to the trapezoid and the first-stage gate side in planar view, and an N-type impurity low-concentration doped region having a square shape which is stacked on the P-type impurity middle-concentration doped region, and wherein electrons from the photodiode are moved in the vicinity of said first stage gate by generating a gradient on the potential of said photodiode.