Solid-state imaging device

A solid-state imaging device in which a plurality of pixels are arranged in a pixel region, each of the plurality of pixels comprising:

• a first semiconductor tier formed on a substrate and having a first semiconductor region, a second semiconductor region that is in contact with the first semiconductor region, and a third semiconductor region that is in contact with the second semiconductor region and that is not in contact with the first semiconductor region;
• a second semiconductor tier formed on the first semiconductor tier and having the second semiconductor region and conductive electrodes that are formed in an outer periphery portion of the second semiconductor region, with insulating films interposed between the second semiconductor region and the conductive electrodes;
• a third semiconductor tier formed on the second semiconductor tier and having the second semiconductor region and a fourth semiconductor region that is formed in an outer periphery portion of the second semiconductor region;
• and
• a fourth semiconductor tier formed on the third semiconductor tier and having a fifth semiconductor region that is in contact with the second semiconductor region,
• wherein the second semiconductor region and the fourth semiconductor region in the third semiconductor tier form a photodiode that stores signal charges generated in the pixel through exposure to electromagnetic energy waves,
• wherein the fourth semiconductor region, which functions as a gate, the second semiconductor region, which functions as a channel, and the first semiconductor region and the fifth semiconductor region, one of which functions as a drain and the other of which functions as a source, form a junction transistor that reads out a pixel signal by measuring a signal current that changes in accordance with an amount of signal charges stored in the photodiode,
• wherein the conductive electrodes, which function as a gate, the second semiconductor region, which functions as a channel, and the third semiconductor region, which functions as a drain, form a MOS transistor that discharges the signal charges stored in the photodiode to the third semiconductor region,
• wherein the first semiconductor region is electrically connected to a first external circuit disposed outside the pixel region,
• wherein the third semiconductor region is electrically connected to a second external circuit disposed outside the pixel region,
• wherein the conductive electrodes are electrically connected to a third external circuit disposed outside the pixel region,
• wherein the fifth semiconductor region is electrically connected to a fourth external circuit disposed outside the pixel region, and
• wherein at least the third semiconductor tier and the fourth semiconductor tier form an island-shaped structure.