An all-implanted CCD/CMOS process

A process has been developed that combines double-polysilicon, surface-type, n-channel charge-coupled devices (CCD´s) with silicon-gate CMOS circuits on the same substrate. The process is all ion-implanted (including the getter step), requires only one more masking step than the 18-V CMOS flow, and is fully compatible with the 5-µm-gate-length silicon-gate Planox (localized oxidation of silicon) CMOS process. To demonstrate the design flexibility afforded by the availability of both p- and n-channel transistors, CCD shift registers with CMOS peripheral circuits and a silicon-gate CMOS operational amplifier have been designed and characterized. Low-pass and band-pass filters have also been designed and characterized and found to be comparable with those fabricated through the conventional CCD/NMOS process.