Patent ID: 7061033

Claim:
A solid-state imaging device, comprising: a pixel array having a plurality of unit pixels, each unit pixel including a photo diode and an insulated gate field effect transistor that detects a photocharge; and a control circuit that controls an operation of the pixel array, the control circuit including a voltage generating circuit, a vertical control circuit and a horizontal control circuit, the control circuit configured to be capable of discharging a charge in the insulated gate field effect transistor by applying a gate voltage and a source voltage to the insulated gate field effect transistor via the vertical and horizontal control circuits, the photo diode and the insulated gate field effect transistor sharing a well region of a first conductivity type that is formed in a semiconductor layer of a second conductivity type, the semiconductor layer of the second conductivity type formed on a semiconductor substrate of the first conductivity type; the insulated gate field effect transistor comprising: a source diffused region of the second conductivity type formed on a surface of the well region; a drain diffused region of the second conductivity type formed on the semiconductor layer; a gate electrode formed over the well region between the drain diffused region and the source diffused region with a gate insulating film therebetween; a channel region formed in the surface of the well region under the gate electrode and having an impurity layer of the second conductivity type; and a heavily doped buried layer of the first conductivity type formed under the channel region in the well region and near the source diffused region, having an impurity concentration higher than that of the well region, and being an accumulation region that accumulates a charge of a given conductivity type generated in response to light incident on the photo diode; and the control circuit being configured to apply predetermined voltage to the source diffused region and the gate electrode, respectively, by which the channel region is brought into a conductive state, so as to bias a junction region formed of the semiconductor substrate and the semiconductor layer in a forward direction, and the control circuit accumulates a predetermined amount of the charge of a predetermined conductivity type in the accumulation region thereby, and thereafter, discharges the charge of a predetermined conductivity type accumulated in the accumulation region.