US Patent 7091463 Solid state image pickup device with polysilicon transfer electrodes

Each transfer electrode of a charge transfer unit is made of a main electrode layer and subsidiary electrode layers formed on the side walls of the main electrode layer. The upper surfaces of the transfer electrodes are flush with each other. A charge coupled device having a practically sufficient charge transfer efficiency can be provided. If this charge coupled device is used for an image pickup apparatus, the distance between photoelectric conversion elements and micro lenses can be shortened.