Charge coupled device capable of efficiently transferring charge

A charge coupled device comprising:

• a semiconductor substrate of a first conductivity type;
• a channel region of a second conductivity type formed in a surface area of said semiconductor substrate, extending in one direction and serving as a transfer channel;
• charge supplying means substantially adjacent to said channel region in the lateral direction of said channel region, for supplying charge to said channel region;
• electrode means insulated from said channel region, for applying a control voltage to said channel region to transfer charge through said channel region;
• potential control means for efficiently transferring small amounts of charge through at least one subregion of said channel region while transferring large amounts of charge through the entire channel region, including a plurality of electrical barrier regions formed in said channel region extending in said one direction substantially throughout said transfer channel and containing an impurity of the first conductivity type, the electrostatic potential energy of each of said electrical barrier regions being set at a level higher than that of said transfer channel and lower than that of said substrate outside of said transfer channel when said control voltage is applied thereto;
• and
• an output circuit to which the charge transferred through said channel region is supplied;
• wherein said electrical barrier regions have different lengths to cause the transferred charge to be gradually combined at an end portion of said channel region.