Solid-state imaging device

Abstract

Capacitance between a detection capacitor and a reset transistor is the largest among the capacitances between the detection capacitor and transistors placed around the detection capacitor. In order to reduce this capacitance, it is effective to reduce the channel width of the reset transistor. It is possible to reduce the effective channel width by distributing, in the vicinity of the channel of the reset transistor and the boundary line between an active region and an element isolation region, ions which enhance the generation of carriers of an opposite polarity to the channel.

What is claimed is: 
     
         1 . A solid-state imaging device comprising:
 a semiconductor substrate;   a photodiode, formed in the semiconductor substrate, that performs photoelectric conversion of incident light into signal charge;   a transfer transistor, formed on the semiconductor substrate, that transfers the signal charge accumulated in the photodiode;   a detection capacitor, formed on the semiconductor substrate, that accumulates the signal charge transferred by the transfer transistor; and   a reset transistor, formed on the semiconductor substrate, that discharges, into a drain, the signal charge accumulated in the detection capacitor; and   a trench isolation, formed on the semiconductor substrate, that surrounds an active region of the photodiode, the transfer transistor, the detection capacitor and the reset transistor,   wherein ions are distributed in at least a first boundary between an active region directly below a gate electrode of the reset transistor and the trench isolation region, the ions enhancing generation of carriers of an opposite polarity to a polarity of carriers in a channel below the gate electrode of the reset transistor, and   wherein the reset transistor has an effective gate width shorter  25  than an effective gate length.