Patent ID: 7955924

Claim:
A method of manufacturing an image sensor, the method comprising: forming a gate insulating film and an undoped gate conductive film on a semiconductor substrate; doping the gate conductive film with a first-conductive-type dopant; forming a transfer gate pattern by patterning the gate insulating film and the gate conductive film after the doping of the gate conductive film; forming a first mask that exposes a first section of the transfer gate pattern and a top surface of the semiconductor substrate adjacent to the first region of the transfer gate pattern; forming a first-conductive-type photodiode in the semiconductor substrate by implanting the first-conductive-type dopant by using the first mask as an ion implantation mask; forming a second-conductive-type photodiode by implanting a second-conductive-type dopant into the exposed first section of the transfer gate pattern and a surface of the first-conductive-type photodiode adjacent to the exposed first section of the transfer gate pattern by using the first mask as an ion implantation mask, the concentration of the second-conductive-type dopant being less than the concentration of the first-conductive-type dopant of the gate conductive film; removing the first mask; forming a second mask that exposes a second section of the transfer gate pattern and the top surface of the semiconductor substrate adjacent to the second section of the transfer gate pattern; and forming a first-conductive-type floating diffusion region in the semiconductor substrate adjacent to the second section of the transfer gate pattern by using the second mask as an ion implantation mask.