New technologies to improve a photo-sensitivity and to reduce a shutter-voltage of the vertical over-flow-drain (VOD) have been developed for CCD image sensors. A 40% photo-sensitivity improvement was obtained by forming an anti-reflection film over the photodiode, in addition to reducing the thickness of player formed at the photodiode surface. A VOD shutter-voltage reduction from 31 V to 18 V was successfully obtained by using an epitaxially-grown substrate with double impurity concentration layers.
