An interline transfer CCD for a single sensor 2/3" color camera

Abstract

A 492(V) × 400(H) interline transfer CCD imager was designed and fabricated for a single sensor 2/3" color camera use. One unit cell consists of a PN junction photodiode, a buried channel vertical CCD and an overflow drain. In spite of the complicated structure having various functional parts packed in a small area, a high aperture ratio of 35% is still maintained. This was realized by designing the vertical CCD as small as possible, taking the narrow channel effect into consideration. The vertical CCD is driven by four phase clocked pulses during signal charge transfer and by single phase clocked pulses during the blanking period to sweep out leakage photo-carriers for anti-smearing. Other features employed in this device are double poly-Si electrode structures, assuring better production yields, and P/N epitaxial wafers, reducing color signal mixture and blooming effects. Color pictures are obtained by a special hybrid color filter, in which blue parts are made of a dichroic filter giving a good sensitivity and a high reliability.