490 (V) multiplied by 510(H)-ELEMENT CCD IMAGE SENSOR USING A SHALLOW FLAT P-WELL.

Abstract

A 2/3 double prime -format 490 multiplied by 510-element interline-transfer CCD image sensor employing a shallow flat p-well (SFPW) structure is developed. This realizes an increase in photoelement count for higher resolution, an increase in aperture ratio for higher sensitivity, and a reduction in smear. Incorporating a SFPW in imaging area facilitates shrinking the cell due to the lack of lateral diffusion, and reduces smear level because the depleted p-well prevents the diffusion of photogenerated carriers to the vertical shift registers. In addition, it offers smooth and high spectral response and almost eliminates response change caused by signal charge storage. The device has a horizontal resolution of 380 TV lines, an aperture ratio of 34%, and a smear level of-70 dB at 550 nm wavelength.