In a solid-state imaging device, for example, a CMOS image sensor, which is a kind of X-Y address-type solid-state imaging device, the operation of successively scanning and reading out photocharges generated by and accumulated in a photoelectric conversion section, pixel by pixel or row by row, is performed. In the case of the sequential scanning, in other words, if the rolling shutter is adopted as an electronic shutter, it is not possible to agree the start time and end time of exposure for accumulating photocharges in all pixels. Therefore, there is a problem with the sequential scanning that various distortions occur in an imaged image upon imaging a moving subject.
For sensing applications that require imaging of a subject that moves at high speeds and the simultaneity of an imaged image, which cannot tolerate this type of image distortion, a global shutter that executes the start and end of exposure at the same timing on all pixels in a pixel array section is adopted as an electronic shutter. In order to realize the global shutter, an embedded MOS capacitor, for example, is provided as a region to accumulate photocharges, that is, a photocharge accumulation section, apart from a photodiode being a photoelectric conversion section (refer to Patent Document 1, for example).
However, in order for an embedded MOS capacitor to receive all photocharges generated by photoelectric conversion in a photodiode and accumulated therein upon global shutter operation, the embedded MOS capacitor needs a saturation charge amount equal to or more than that of the photodiode. Conversely, considering them in the same unit pixel size, the area of the photodiode is significantly reduced since the embedded MOS capacitor exists in the unit pixel. Therefore, there is a problem that the saturation charge amount of the photodiode is reduced.
As a measure against it, proposed is a technology for accumulating photocharges generated by photoelectric conversion in a photodiode in both of the photodiode and an embedded MOS capacitor (refer to Patent Document 2, for example). According to the related art, the saturation charge amount is the sum of the saturation charge amounts of the photodiode and the embedded MOS capacitor.