Patent ID: 7227206
Filing Date: 2007-06-05
Classification: H01L

Abstract:
1. A solid state image sensor comprising in each pixel: a semiconductor region of a first conductive type provided on a semiconductor substrate; a photodiode provided in the semiconductor region; a transfer gate for transferring photocharges accumulated in the photodiode; and a diffusion region for receiving the transferred photocharges, wherein the photodiode includes a first accumulation region composed of a semiconductor of a second conductive type and a second accumulation region provided in contact with the first accumulation region, at a position deeper in a depth direction than the first accumulation region, and composed of a semiconductor of the second conductive type, and wherein the first accumulation region comprises a portion extending toward an end of the transfer gate, and the second accumulation region extends along the first accumulation region, except for the portion extending toward the end of the transfer gate, in a direction transverse to the depth direction, wherein the semiconductor region serves as a first semiconductor region, and a second semiconductor region of the first conductive type is provided on a front side of the photodiode and in contact with the first accumulation region, and wherein the following condition is satisfied: where Rp 2 represents the mean range of ion implantation for the first accumulation region, and Xj represents the depth of the junction between the first accumulation region and the second semiconductor region.