A Fundamental Comparison of Incomplete Charge Transfer in Charge Transfer Devices

Since the introduction of the charge-coupled device 1 (CCD) and the bucket-brigade shift registers, 2-4 there have been a number of proposed modifications to the basic structures in order to achieve specific performance goals. 5-10 It is the purpose of this paper to analyze the mechanisms of charge transfer in these devices and to compare the characteristics of the incomplete charge transfer in each. In this way one can evaluate the relative merits and limitations of these modified charge transfer devices (CTD's). In a recent article, the authors 11 presented a general analysis of incomplete charge transfer in CTD's. Using a lumped model12-13 to characterize the dynamics of the charge transfer, it was possible to calculate a, the small-signal coefficient of incomplete transfer, in terms of single-device, small-signal characteristics. It was found that three contributions to incomplete transfer are common to all charge transfer shift registers: an intrinsic transfer rate contribution, an output conductance or feedback contribution, and a storage-capacitance modulation contribution. A significant feature of that calculation was that cach of these contributions could be expressed analytically in terms of