A monolithic SAW-CCD

IN RECENT YEARS the charge-coupled device’ has been creating a great deal of interest for applications in memory, signal processing and imaging. The incentive for the interest lies in the simplicity in structure and high density. However, the CCD technology has a number of drawbacks which limit the density, the speed and the processing simplicity. For instance, in a typical CCD structure three or four phase clocks arc required to transfer the charges, multilevel metallization is required to effect the multiphase clocks, buried channel is required to improve the speed, and for imagers, separate charge storage and transfer areas must be provided because of the masking of the clock busses. This paper will offer a study of a way to circumvent these problems by means of surface acoustic waves involving a monolithic device, whose operation will be described.