Bulk channel charge-coupled device with blooming suppression

A radiant energy sensor of the bulk-channel charge coupled type with blooming suppression, comprising a semiconductor body having an elongated semiconductor layer of first type conductivity and forming plural storage and transfer signal channels for first type majority signal carriers generated by incident radiant energy, means for electrically isolating the signal channels from their surroundings, means including electrodes arranged adjacent a surface of the body and the signal channels and capable when the electrodes are electrically biased of forming a depletion zone throughout the channel thickness and of forming in the channels a series of potential wells having, within the channels and separated in the transfer direction by potential barriers, potential minima where majority carriers can be stored and further capable of transferring the carriers from well to successive well along the channel interior, and means for draining excess majority carriers comprising a common semiconductor drain zone of a first type conductivity arranged in the body between the signal channels and directly connected to the signal channels and when electrical bias is applied cooperating with the electrical isolation means to establish between the drain zone and the storage wells an overflow potential barrier which maintains the electrical isolation of the signal channels but whose height at locations each adjacent a storage well is lower than that of the potential barrier between successive wells during storage thereby to preferentially attract excess majority carriers overflowing the storage wells, said isolating means comprising in the body plural intermediate regions of first-type conductivity each separating a signal channel from the drain zone, each said intermediate region having a thickness and a doping concentration at which a depletion zone can be obtained throughout its thickness by means of an electric field, and further comprising, separate from the transfer electrodes, separate intermediate electrodes provided over each intermediate region and spaced from each other by means of which an electric field can be formed capacitively in each intermediate region so as to obtain the said overflow potential barrier between the adjacent signal channel and the drain zone, said isolating means further including a semiconductor zone of the second type conductivity extending in the body alongside and bounding each signal channel on the side, viewed on the surface, opposite to the said drain zone.