Image sensor with a gate electrode between the photoelectric conversion region and the charge detection region, the gate electrode comprising p-type and n-type regions adjacent to one another and method of fabricating the same

A method of fabricating an image sensor, comprising:

• providing a semiconductor substrate;
• and
• forming a charge transfer structure on the semiconductor substrate including
• forming a gate insulating film on a channel region in the semiconductor substrate between a photoelectric conversion region and a charge detection region, and
• forming a transfer gate electrode on the gate insulating film consisting of a first conductivity type impurity-doped region and a second conductivity type impurity-doped region adjacent to each other,
• wherein each of the first conductivity type impurity-doped region and the second conductivity type impurity-doped region consists of a singe region doped at a same concentration, and
• wherein forming the transfer gate electrode includes forming the first conductivity type impurity-doped region and the second conductivity type impurity-doped region in the transfer gate electrode such that a peak of a potential barrier formed below the transfer gate electrode is closer to the photoelectric conversion region than the charge detection region.