Photodiode of CMOS image sensor and method for manufacturing the same

A method for manufacturing a photodiode of a CMOS image sensor comprising:

• forming a lightly doped P-type epitaxial layer on a heavily doped P-type semiconductor substrate;
• forming a device isolation film and an N-type photodiode region in a surface of the epitaxial layer;
• forming a first insulating film on the lightly doped P-type epitaxial layer including the photodiode region;
• patterning the first insulating film to open a portion of the lightly doped P-type epitaxial layer between the device isolation film and the photodiode region, and to open another portion of the lightly doped P-type epitaxial layer for a gate formation region;
• forming a photoresist film pattern on the first insulating film to cover the gate formation region on the lightly doped P-type epitaxial layer;
• forming a heavily doped P-type diffusion region only in the opened portion of the lightly doped P-type epitaxial layer between a sidewall of the device isolation film and a sidewall of the photodiode region by implanting P-type ions into the opened portion of the lightly doped P-type epitaxial layer using the photoresist film pattern and the patterned first insulating film as a mask;
• removing the photoresist pattern;
• and
• forming a gate electrode on the lightly doped P-type epitaxial layer and inside the gate formation region.