a cmos imager having reduced dark current and methods of forming the same . a nitrided gate oxide layer having approximately twice the thickness of a typical nitrided gate oxide is provided over the photosensor region of a cmos imager . the gate oxide layer provides an improved contaminant barrier to protect the photosensor , contains the p + implant distribution in the surface of the p + pinned region of the photosensor , and reduces photon reflection at the photosensor surface , thereby decreasing dark current .