Patent ID: 7348651
Filing Date: 2008-03-25
Classification: H01L

Abstract:
1. A semiconductor structure to reduce or eliminate electrical leakage between a pinned photodiode and a shallow trench isolation structure, the semiconductor structure comprising: a first region of a first impurity type formed beneath a surface of a semiconductor substrate of a second impurity type and disposed between portions of a shallow trench isolation (STI) structure that surrounds the first region; a semiconductor well of a second impurity type laterally separating the first region from the STI structure at all points on an inner periphery of the STI structure and including a damaged portion adjacent the STI structure at all points on the inner periphery of the STI structure and facing the first region; a substrate portion of the semiconductor substrate interposed between the first region and the semiconductor well all locations on an inner periphery of the semiconductor well; a second region of the second impurity type covering the first region and the substrate portion and overlapping at least part of the semiconductor well at all points along the inner periphery of semiconductor well, the second region formed within the semiconductor substrate and extending downwardly from the surface; an expandable depletion region formed along a boundary between the first region and the substrate portion, a lateral spacing between the first region and the adjacent damaged portion sufficient to prevent the depletion region from expanding into the damaged portion at a maximum expansion of the depletion region, and the first region having a lower boundary more than about 0.8 microns below the surface.