High-resolution CCD image sensors with reduced smear

Two types of interline transfer CCD image sensors with reduced smear signal were developed, one for a 525-line TV system (EIA) and one for a 625-line system (CCIR). An MOS diode is employed as a sensing element to realize negligibly small lag compared with that of a junction diode. The EIA and CCIR version have effective number of pixels of 510 × 492 and 500 × 582, respectively. Smear is reduced down to -92 dB by fabricating the vertical shift register on the p-well. In spite of the shrunken element area, the blue sensitivity similar to that for a conventional 384 × 491 CCD imager [1] is obtained by optimization of the film thickness on the diode. Resolution as high as 330 TV lines in color is also attained.