Performance limitations of two phase CCD's

There are several different techniques available for achieving two-phase operation. These are discussed and compared. The performance of two-phase CCD's (charged coupled devices) fabricated with a coplanar, N-channel, double-level polysilicon gate process is described and compared between devices fabricated with stepped-oxide, implanted barriers and offset-gate structures. A comparison between surface and buried channel devices is also made. A basic three-phase charge transfer system was studied, and whilst such structures are simple in concept, they are difficult to operate. Performance limitations of a number of two-phase CCD structures when operating in both two-phase and the uniphase mode are discussed. Their performance is compared to the equivalent three-phase device.