Semiconductor charge transfer device having a decoupling gate for stopping reverse charge flow

Claim 1

A semiconductor charge transfer device comprising: a semiconductor charge transfer element including a plurality of transfer electrodes on an insulating layer formed on a semiconductor substrate and a detection node formed on the semiconductor substrate; potential barrier means comprising an output electrode connected via a direct short circuit connection to a potential source of fixed value for signal charge packets provided between a final stage cell of the semiconductor charge transfer element and the detection node; a differential detecting circuit of flip-flop type having a drive transistor for driving a load directly coupled with the detection node; wherein said potential barrier means provided a potential barrier against a low level of the detection node when the drive transistor is conductive and said potential source of fixed value is connected to the low level side of said drive transistor; said semiconductor charge transfer element, having a multiplex electrode per bit (ME/B) structure, comprising: N charge transfer channels arranged in parallel whose inputs are connected to a common input means and outputs to a common output means, which includes a merging shift register of one bit storage cell including a barrier, a storage region, and a fixed barrier region, these regions being common to all said N charge transfer channels; said charge transfer channels each including a semiconductor substrate, an insulating layer formed on said semiconductor substrate, P transfer electrodes per one channel disposed on said insulating layer, the N corresponding transfer electrodes of said N charge transfer channels being electrically connected together, and means for forming a potential barrier in part at a prescribed portion of a semiconductor region under each of a series of said P transfer electrodes of each of said charge transfer channels such that a number M of said P charge transfer electrodes, where M is less than P, remain dedicated as charge transfer electrodes, in response to application of a potential for a storage mode to the transfer electrode thereby to form a potential well in the remaining part of said semiconductor region for storing a signal charge packet, and said potential barrier being lowered in potential compared to the potential barrier being in the storage mode in response to application of a potential for the transfer mode to the transfer electrode; means for applying N-phase non-overlapping offset clock pulse signals to said transfer electrodes of said N charge transfer channels, said clock pulse signals each being biased to low level for storage and pulsed to high level for transfer in order that a series of N transfer electrodes in each of said charge transfer channel are successively set to the transfer mode in the direction opposite to a charge transfer direction; and means for forming a fat "0" potential barrier in part at the charge incoming side of a semiconductor region under each of transfer electrodes disposed between the input of said each charge transfer channel and the set of M transfer electrodes, when said transfer electrodes are at the storage mode, to store a fat "0" charge in the remaining part of said semiconductor region.