Solid-state image pickup device and method for producing the same

摘要

A solid-state image pickup device includes an element isolation insulating film electrically isolating pixels on the surface of a well region; a first isolation diffusion layer electrically isolating the pixels under the element isolation insulating film; and a second isolation diffusion layer electrically isolating the pixels under the first isolation diffusion layer, wherein a charge accumulation region is disposed in the well region surrounded by the first and second isolation diffusion layers, the inner peripheral part of the first isolation diffusion layer forms a projecting region, an impurity having a conductivity type of the first isolation diffusion layer and an impurity having a conductivity type of the charge accumulation region are mixed in the projecting region, and a part of the charge accumulation region between the charge accumulation region and the second isolation diffusion layer is abutted or close to the second isolation diffusion layer under the projecting region.

主权项

1. A method for producing a solid-state image pickup device in which a plurality of pixels including a photoelectric conversion part having a charge accumulation region accumulating signal charges is two-dimensionally arrayed in a well region formed on a semiconductor substrate, the method comprising the steps of:
forming an element isolation insulating film on the surface of the well region, the element isolation insulating film electrically isolating the pixels; forming a first isolation diffusion region in the well region, the first isolation diffusion region electrically isolating the pixels; forming a second isolation diffusion region in the well region, the second isolation diffusion layer electrically isolating the pixels and a width of said second isolation diffusion region is smaller than that of said first isolation diffusion region; and forming the photoelectric conversion part for each pixel in the well region in which the photoelectric conversion part is electrically isolated from each other by the element isolation insulating film, the first isolation diffusion region, and the second isolation diffusion region, wherein the step of forming the photoelectric conversion part includes the steps of implanting an impurity ion for forming the charge accumulation region in the well region surrounded by the first isolation diffusion region and the second isolation diffusion region; and thermally diffusing the impurity implanted in the well region so that a part of the charge accumulation region corresponding to the boundary between the charge accumulation region and the second isolation diffusion region is disposed under the first isolation diffusion region, and the first isolation diffusion region is formed in a state in which an impurity having the conductivity type of the first isolation diffusion region and an impurity having a conductivity type of the charge accumulation region are mixed.