Semiconductor image sensor having ccd shift register

Abstract

In a semiconductor image sensor composed of a plurality of charge-coupled photo-sensor elements, each of said photo-sensor elements comprises a substrate of one conductivity type with an insulating layer thereon, a first electrode on the insulating layer having a first electrode portion spaced from the substrate by a thickness of said insulating layer for defining, in combination with a potential applied to the first electrode, a first region in the substrate which is a potential well for minority charge carriers therein, a second electrode in the insulating layer having second and third electrode portions which are respectively adjacent to and remote from the first electrode, and which are spaced from the substrate by different thicknesses of the insulating layer for defining, in combination with a potential applied to the second electrode, adjacent second and third regions in the substrate which are respectively a potential barrier to the potential well in the first region and a potential well for the minority charge carriers relative to the potential barrier of the second region, and a third electrode in the insulating layer spaced from the substrate and second electrode by the insulating layer and having a fourth electrode portion overlapping the third electrode portion, with at least one of the second and third electrodes having a cutout portion cooperating with an adjacent portion of the other of such electrodes to define an opening above the aforementioned first region which is a potential well.