Solid-state imaging device and method of manufacturing the same

A solid-state imaging device, comprising:

• a pixel array having a plurality of pixels arranged in a matrix;
• each of the pixels including:
• a photo diode that generates carriers depending on the intensity of incident light;
• an accumulation region that accumulates the generated carriers;
• an insulated-gate output transistor that outputs a signal according to a threshold voltage that changes depending on a number of the carriers accumulated in the accumulation region;
• and
• an insulated-gate clear transistor that discharges the carriers accumulated in the accumulation region, the accumulated carriers being discharged through a channel region of the clear transistor, and
• the pixels each further including:
• a pixel-forming region of a second conductivity type that is formed on a semiconductor substrate of a first conductivity type and where one of the pixels is formed;
• a buried region of a first conductivity type that is formed in the pixel-forming region and that includes a first partial buried region formed at a relatively deep position and having a relatively low impurity concentration and a second partial buried region formed at a relatively shallow position and having a relatively high impurity concentration, a junction region between the first partial buried region and the pixel-forming region forming the photo diode, the second partial buried region forming the accumulation region;
• and
• a discharging region of a first conductivity type that is formed in the pixel-forming region and into which carriers discharged from the accumulation region flow;
• an output transistor that includes a first gate electrode that is formed over the pixel-forming region above the accumulation region through an insulating film;
• and
• the clear transistor including a second gate electrode that is formed over the pixel-forming region between the buried region and the discharging region.