Image sensors for reducing dark current and methods of manufacturing the same

A method of manufacturing an image sensor, comprising:

• implanting impurities of a first conductivity type in a substrate of the first conductivity type to define a first channel region which extends to a first depth from a surface of the substrate;
• implanting impurities of a second conductivity type in the substrate surface to define a second channel region which is located over the first channel region and extends to a second depth from the substrate wherein the first depth is greater than the second depth;
• forming a transfer gate electrode over the substrate surface and over the first and second channel regions;
• implanting impurities of the first conductivity type in the substrate to define a hole accumulated device (HAD) region which extends to a third depth from the substrate surface and which is adjacent the gate electrode;
• implanting impurities of the second conductivity type in the substrate to define a photodiode region which is buried in the substrate and extends to a fourth depth from substarte surface, wherein the fourth depth is greater than the third depth;
• implanting impurities of the second conductivity type in the substrate to define a diffusion region which electrically contacts the second channel region,
• wherein the HAD region is located over the photodiode region, and
• wherein the image sensor is a CCD image sensor, and wherein the diffusion region is a buried channel charge coupled device (BCCD) region of the CCD image sensor.