METHOD FOR FABRICATING IMAGE SENSOR AND IMAGE SENSOR FABRICATED THEREBY

A method for fabricating an image sensor is provided to reduce a potential barrier generated by an impurity density difference between regions in a transfer gate pattern by forming an image sensor after impurities of a first conductivity type are implanted into a transfer gate pattern. A gate insulation layer and a gate conductive layer doped with impurities of a first conductivity type are formed on a semiconductor substrate(102). The gate insulation layer and the gate conductive layer are patterned to form a transfer gate pattern. A photodiode of the first conductivity type is formed at one side of the transfer gate pattern and a photodiode of a second conductivity type is formed on the photodiode of the first conductivity type. A floating diffusion region of the first conductivity type is formed in the substrate at the other side of the transfer gate pattern to complete a transfer gate electrode. In forming a gate conductive layer, the impurities of the first conductivity type can be doped at a dosage that can invert the impurities in the photodiode of the second conductivity type.