Patent ID: 7236197

Claim:
A solid-state image sensor comprising: a semiconductor substrate; and a plurality of pixels formed in the semiconductor substrate and each having an accumulation period of signal charges, signal readout period and discharge period of the signal charges, and each of the plurality of pixels including: a first semiconductor region of a first conductive type formed in the semiconductor substrate; a source region of the first conductive type formed in a surface region of the first semiconductor region; a drain region of the first conductive type which is formed apart from the source region in the surface region of the first semiconductor region and to which different voltages are supplied in the accumulation period of the signal charges in the pixel, signal readout period, and discharge period of the signal charges; a second semiconductor region of the first conductive type electrically connected to the drain region and formed in the surface region of the first semiconductor region; a third semiconductor region which is formed in the first semiconductor region under the second semiconductor region and electrically connected to the second semiconductor region and which is of a second conductive type opposite to the first conductive type to accumulate the signal charges in accordance with an incident light; and a fourth semiconductor region of the second conductive type formed in the surface region of the first semiconductor region between the source and drain regions.