Image sensor and method of manufacturing the same

Abstract

Example embodiments disclose an image sensor capable of preventing or reducing image lag and a method of manufacturing the same. Example methods may include forming a gate insulating film and a gate conductive film doped with a first-conductive-type dopant on a semiconductor substrate; forming a transfer gate pattern by patterning the gate insulating film and the gate conductive film; and fabricating a transfer gate electrode by forming a first-conductive-type photodiode in the semiconductor substrate adjacent to one region of the transfer gate pattern, by forming a second-conductive-type photodiode on the first-conductive-type photodiode, and by forming a first-conductive-type floating diffusion region in the semiconductor substrate adjacent to the other region of the transfer gate pattern.

1 . An image sensor, comprising:
 a semiconductor substrate;   a photodiode including a first-conductive-type photodiode in the semiconductor substrate and a second-conductive-type photodiode on the first-conductive-type photodiode;   a first-conductive-type floating diffusion region; and   a transfer gate electrode.   
     
     
         2 . The image sensor of  claim 1 , wherein the transfer gate electrode includes a first section that is adjacent to the photodiode and includes a mixture of a first-conductive-type dopant and a second-conductive-type dopant and a second section that is adjacent to the floating diffusion region and includes the first-conductive-type dopant. 
     
     
         3 . The image sensor of  claim 2 , wherein a concentration of the first-conductive-type dopant is greater than a concentration of the second-conductive-type dopant. 
     
     
         4 . The image sensor of  claim 2 , wherein the first-conductive-type is n-type, and the second-conductive-type is p-type. 
     
     
         5 . The image sensor of  claim 2 , wherein the first-conductive-type dopant is implanted at a concentration sufficient to invert the second-conductive-type dopant. 
     
     
         6 . The image sensor of  claim 1 , wherein the first-conductive-type floating diffusion region is in an LDD structure.