Solid-state image pick-up device having electric field for accelerating electric charges from photoelectric converting region to shift register

Claim 1

A solid-state image pick-up device comprising a) a semiconductor substrate of a first conductivity type, b) a plurality of photo-electric converting regions having first impurity regions of a second conductivity type opposite to said first conductivity type, respectively, and formed in a surface portion of said semiconductor substrate at spacings, said plurality of photo-electric converting regions respectively having second impurity regions of said first conductivity type overlapped with the associated first impurity regions except for outlet subregions so that said first impurity regions are buried beneath the associated second impurity regions, said outlet subregions being inside said semiconductor substrate, c) a shift register having a charge transfer region of said second conductivity type separated from said first impurity regions by respective channel forming regions of said first conductivity type, each of said channel forming region being exposed to a surface of said semiconductor substrate, d) a thin insulating film covering said channel forming regions and said outlet subregions of said first impurity regions, said outlet subregions being contiguous to said channel forming regions, respectively, and e) a transfer gate electrode extending on said thin insulating film, and having a boss portion provided for said outlet subregions and said associated channel forming regions and projections each projecting from said boss portion and shaped in such a manner as to create an electric field over each outlet subregion and said associated channel forming region for accelerating carriers from said each outlet subregion through said associated channel forming region to said shift register, each of said projections having a trapezoidal configuration decreased in width toward the leading end thereof.